Rainer Gross and Noel Solomons
The nutritional status of populations depends to a great extent on environmental conditions. The relationship between nutrition and environment was taken into account in the conceptual framework introduced by UNICEF in the early 90s. In this framework environment was depicted as an important causal factor for disease, leading to malnutrition. This issue of SCN News explores linkages between nutrition and the environment in a much broader context, and raises emerging policy issues. Enviro n ment - encompassing soil degradation, global warming, waste disposal and other factors - has far more pervasive implications for the biosystem nutrition than perhaps was evident when the conceptual framework was first described.
Environment has a far more pervasive implication for
nutrition than perhaps was evident in the early 90s
This topic is picked up as well in the essay by Hazell using the contrast of food security challenges in the densely-populated and intensively farmed Asian region with those of the rurally entrenched and remote populations of Sub-Saharan Africa. Hazell provocatively argues that much of the degradation in Africa - soil erosion, loss of soil fertility and deforestation - is the consequence of traditional agricultural practices, and further that upgrading the infrastructure towards more intensive and modern farming will reverse the environmental degradation involved with producing human food in Africa. Given the fragility of Sub-Saharan ecosystems, however, one wonders whether they bear extrapolation to the practices employed in Asia, and whether or not the slash-and-burn practices that have filled the air with smoke from Indonesia to Malaysia justify characterising Asian approaches to food production as necessarily modern and environmentally friendly. Here, conflicts between economic and environmental development goals become obvious.
A paper by staff of the Worldwatch Institute, entitled The Climate Wild Card, probes some of the possible impacts of climate change on food production and food security. Issues raised here are all the more critical given the failure of recent efforts by 170 countries meeting in the Hague in November to translate the 1997 Kyoto Accord into enforceable treaty to reduce greenhouse gases. Last years report to the ACC/SCN by the Commission on the Nutrition Challenges of the 21st Century began to grapple with the implications of supplying food to the worlds population in the context of the stresses on the physical and human environments, and an extract from that report illustrates some proposed practical steps.
Micronutrient malnutrition or "hidden hunger" became a major concern of public nutrition during preparations for the World Summit for Children in the late 80s. Solomons sets a framework for analysis of the interactions between micronutrient deficiencies and pollution beyond the classical example of lead toxicity and iron status. Solomons shows that a series of direct and indirect interactions from the dietary side toward the environmental, and vice versa, frame the global campaign to eliminate micronutrient deficiencies among vulnerable populations. A group of consultants engaged by the International Atomic Energy Agency met recently to discuss the relationship between environmental pollution and nutritional status (see p 64). Recommendations were made to IAEA for research in which nuclear analytical and isotope techniques may play a prominent role.
In her article on environmental contaminants in breast-milk, Harriet Kuhnlein discusses the problems of toxic residues - both organic and inorganic - polluting the marine environment which is the habitat of fish and sea mammals in the Arctic region. The safety of maternal milk, and hence the wisdom of a policy to promote exclusive breastfeeding in the first semester of life, is challenged by the growing concentration of heavy metals and organochlorines in the waters of Hudson and Baffin Bays. Few detailed studies can be cited to guide any new policy directions, but this problem is of concern to advocates supporting breast-feeding. Penny Van Esterik takes the approach that breastfeeding advocates have a responsibility to critique the evidence, as well as the manner in which this information is manner in which this information is communicated to policy makers and the general public. The author points out that breastmilk is not necessarily more contaminated than other tissues, such as blood or body fat, it is simply easier to collect and measure. As an adjunct to Van Esteriks paper a Guideline Statement on Breastfeeding and Dioxins, prepared by International Baby Food Action Network, provides an example of such clear communication. This Statement is especially relevant to the historical meeting this month in Johannesburg where some 122 countries agreed on the text of a legally-binding treaty that will require governments to minimize and eliminate use of persistent organic pollutants.
Food and nutrition policy is, at the same time,
While there is a vast literature on intensive crop production, there is less on intensive livestock production. Jacky Turner describes some of the costs of high-input livestock production as well as the environmental impacts. Demand for animal source protein, already very high in some middle income countries, will continue to accelerate throughout the developing world as incomes rise. Diet choices have a strong impact on the environment. Consequently, food and nutrition policy is, at the same time, environmental policy.
Livestock blood is a major waste-product of meat production. Disposing of livestock blood safely is both difficult and costly. Mäurer and Schümann describe an interesting use for haem iron. This can be extracted from livestock blood, the authors propose, and used in fortification pro-grammes to address iron deficiency anaemia. However, recent developments with regards to infectious zoonotic conditions, namely bovine spongiform encephalopathy (BSE) which leads to variant Creutzfeldt-Jacob (vCJD) disease in humans, highlights the limitations of recycling food products for human consumption within the food chain. It has to be recognized that not only the source of the nutrient fortificant and the food technology employed, but also how consumers perceptions will be important in scaling up.
Is the nutrition community prepared to play its role in monitoring the impacts of industrial materials on the nutrition and health of populations? A set of recommendations made by a group of toxicologists drawn from eight laboratories in six European countries at a recent international conference on Metals and the Brain, illustrates just how complex this task may be - both in terms of the nutritional science, but also in terms of the way in which risk should be communicated to the public. These recommendations concern human exposure to aluminum and possible effects on neurologic al health.
FOOD ACCESSIBILITY, NUTRITION AND ENVIRONMENT
Ulrike Roetten and Michael B. Krawinkel
Adequate food security requires the availability of physical supplies of food as well as household access to such supplies either through production, purchase in the market or other means. However, in order to guarantee nutrition security, food supplies need to meet the specific nutrient requirements of individuals.1 The food-health-care causal framework for nutrition identifies a number of contributing factors to nutrition security (Figure).2
Two factors that have an immediate impact on nutrition are dietary intake and health status. Increased food access will not necessarily improve food utilization when other factors, such as health or social environment, are not favourable.3 Appropriate care for mothers and children, access to health services, and a healthy environment (e.g. sanitation facilities; potable water, health care etc.) are often the missing links to adequate nutrition at the household and individual level.
Food accessibility is ensured when households and all individuals within those households have adequate resources to obtain appropriate foods for a nutritious diet. Household access to food primarily depends on home production, household income and food prices.1 Income and prices are special concerns in urban areas where home food production for consumption is low. For example, in Accra more than 90% of the food consumed is purchased.4 Access to food for the growing population in urban areas in Asia, Africa and Latin America is an important matter of interest for national and international food security strategies.
Figure: Determinants of Nutrition Security
(adopted from UNICEF 1998)About 73 million people will have been added to the world's population each year between 1995 and 2020, a total increase of 32%. An overwhelming 97.5% of the increase in population is expected to occur in the developing world, whose share will increase to 84% of the total population by 2020. About a third of the total population increase is anticipated to occur in just two countries - China and India. Population growth will occur mainly in the cities of the developing world. Whereas the rural population is expected to increase by less than 300 million in the developing world during this period, urban population will double to 3.4 billion in 2020.5 This enormous increase of the urban population demands strategies to secure access to food in cities.
Nutrition - as an outcome of food security - is vulnerable to environmental degradation because access to food is a function of the physical environment. Drought and soil erosion often accompanied by social conflict may seriously disrupt production and acquisition strategies and, therefore, threaten food availability and access. These shocks often lead to a loss of productive assets, e.g. livestock. They also have severe implications for the future productive potential of households and their long-term food security.1
The world's growing population will continue to exert pressure on food supplies. Developing countries will account for about 85% of the 690 million ton increase in the global demand for cereals between 1995 and 2020.5 It is estimated that six to seven million hectares of agricultural land in developing countries become unproductive due to soil erosion alone each year. Waterlogging, salinization, and alkalinization from irrigation damage account for another 1.5 million hectares per year.6 In Central America, nearly one-third of all used land is seriously degraded, including 74% of the agricultural land. In comparison, 19% and 16% of all used land in Africa and Asia, respectively, i.e. 65% and 38% of the agricultural land is seriously degraded.7 When agricultural land becomes infertile, farmers either let the land lie fallow until it recovers or, if there are other land resources, they abandon unproductive lands and move on, often clearing new forest lands to cultivate. The newly cleared land is then farmed and the process is repeated.8
The aim of supporting poor farmers in food production, combined with concerns about excessive dependence on fertilizers, pesticides, and irrigation water, has stimulated interest in an "agroecological approach" to agricultural production. Ideally, the agroecological approach is aimed at reducing the amount of external inputs that farmers use, relying instead on available farm labour and organic material, as well as on improved knowledge and farm management. There is tremendous potential to promote increases in sustainable productivity in small-scale agriculture.5 This concept of sustainable agriculture has the potential to improve food safety and to reduce contamination of groundwa-ter by reducing the use of pesticides and agricultural chemicals. However, in practice there are some constraints to the wide-scale application of sustainable agriculture. Lack of productive soil due to erosion or desertification, problems with yield variability, high labour requirements, organisational constraints and overburden of women may contribute to low acceptance rates of the agroecological approach.
Adding an environmental dimension to food and nutrition security would help to draw attention to these aspects:
· soil health care, water harvesting and management, conservation of biodiver sity and improved post-harvest technologyReferences
· environmental hygiene (e.g. sanitation, access to safe water), and access to qualified health service
· adequate care, especially for children and women,
1. Riely F, Mock N, Cogill B, et al. (1999) Food security indicators and framework for use in the monitoring and evaluation of food aid programs. IMPACT: Food security and nutrition monitoring project. Arlington, Va., U.S.A., Food and Nutrition Technical Assistance Project (FANTA). www.msf.org/intweb99/library/guidenut.htm
2. UNICEF 1998. The state of the world's children 1998. Oxford and New York.
3. Hoddinott J (1999) Operationalizing household food security in developing projects: an introduction. Technical Guide #1. IFPRI, Washington.
4. Zilbermand D, Templeton SR, Khanna M (1999) Agriculture and the environment: an economic perspective with implications for nutrition. Food Policy 24 pp. 211-229.
5. Pinstrup-Andersen P, Pandya-Lorch R, Rosegrant MW (1999) World food prospects: critical issues for the early twenty-first century. IFPRI Food Policy Report, Washington.
6. Kennedy E, Bouis H (1993) Linkages between agriculture & nutrition: implications for policy and research. IFPRI, Washington.
7. Scherr SJ (1999) Soil degradation - a threat to developing country food security by 2020? IFPRI - Food, Agriculture and the Environment Discussion Paper 27, Washington.
Contact: Ulrike Roetten and Michael B. Krawinkel, University of Giessen, Institute of Nutrition, Nutrition in Developing Countries, Wilhelmstrasse 20, D-35392 Giessen/Germany EMail: firstname.lastname@example.org email@example.com
POLICIES FOR ACHIEVING FOOD SECURITY WITHOUT DEGRADING THE ENVIRONMENT
Modern agricultural technologies have transformed the global food situation from one of widespread shortages and famine in the 1960s to one in which there is more than enough food for everyone were it more equitably shared. These advances have been particularly dramatic in Asia and Latin America where cereal yield growth has outstripped population growth, leading to significant gains in the per capita availability of food and calories.
Yet despite these achievements, some 1.2 billion people remain in abject poverty (less than $1/day) and do not get enough to eat. Many more live on nutritionally inadequate diets. About 160 million preschool children are malnourished, with serious implic ations for their future mental and physical capacities. About 90% of the developing worlds poor now live in Asia and Sub-Saharan Africa, and these countries will also need to feed over 1 billion more people by 2020.
This paper contrasts the food security challenges facing the Asian and Sub-Saharan African regions. It also discusses appropriate policies for reducing environmental problems while achieving greater food security.
FOOD SECURITY CHALLENGES IN ASIA
Asias remarkable transition from widespread food deficits in the 60s to national food surpluses today has been accompanied by an equally dramatic reduction in poverty: from one in two Asians in 1970 to one in four today.1 But there is a paradoxical food situation in Asia today.
On the one hand, there are huge numbers of increasingly affluent Asians (an emerging middle class) who are rapidly diversifying and enriching their diets. This has led to a veritable explosion in demand for livestock products, fruits, vegetables and vegetable oils. This in turn has led to rapid growth in livestock production and in demand for feedgrains. The International Food Policy Research Institute (IFPRI), amongst others, is projecting potentially large feed grain imports by Asia in the future. But these growing imports are not driven by basic food security needs. It is not a problem of filling bellies with essential foods, but of meeting the dietary aspirations of the newly affluent. Lester Browns projected foodgrain crisis in China is really a problem of emerging middle-class affluence, not a food insecurity problem.2
Despite this growing food affluence for many, about 800 million Asians live in poverty and have poor access to food; 120 million pre-school children are malnourished. Two thirds of Asias poor live in South Asia. The poor are predominately rural people, and most live in rainfed agricultural areas. In India and China, about one third of the poor live in rainfed areas with limited agricultural potential. These people do not have the means to buy the food they need, despite its ready availability. They desperately need better livelihood opportunities.
There are very favorable opportunities for greater
diversification of Asian agriculture to meet the changing food consumption
patterns of the more affluent
The food insecure in Asia will increasingly become more concentrated in urban ghettoes and less-favored rural areas. T hese people will gain relatively little from the growth just described. To reach them, other, more targeted policies and investments will be required.
These will need to include adequate safety net programs in rural and urban areas (food subsidies, employment programs and training schemes) and also greater investment in the development of less-favored areas. Policy makers have been reluctant to do this in the past, preferring to rely on the trickle down benefits (increased employment and migration opportunities and cheaper food) from investments in high-potential areas. This has proved insufficient: the poor are multiplying faster than they are leaving in many less-favored areas and population densities are likely to increase for at least a few more decades. Without adequate investments in basic infrastructure and human development, less-favored areas will lose out even further as agricultural markets become more commercial and competitive. These people will become victims of market liberalization and globalization, not beneficiaries, with worsening poverty and environmental degradation.
However, with the right policies and investments, many less-favored areas could actually do quite well. For example, unlike crops, livestock and agroforestry can often prosper in zones with poor soils and climate; some less-favored areas can become important eco-tourist attractions in increasingly more affluent societies. Rapid economic growth in Asia is also creating new growth opportunities for non-farming activity in many less-favored areas.
unlike crops, livestock and agroforestry can often
prosper in zones with poor soils and climate
FOOD SECURITY CHALLENGES IN SUB-SAHARAN AFRICA
Sub-Saharan Africa faces a very different situation than Asia today. In fact, it is similar to the Asian situation of the early 60s with widespread poverty and malnutrition, large national food deficits, and high and increasing dependence on food imports and other concessionary aid.
Also like pre-green revolution Asia, yields are very low and there is tremendous potential for increasing them with the right technologies.
But, there is also a big difference between Sub-Saharan Africa today and pre-green revolution Asia. Rural Africa has a much lower density of infrastructure and weaker institutions to serve agriculture. This means that market access and transport costs are daunting obstacles to development. Investments in sophisticated technologies are simply not economical when the market price of fertilizer is three to five times the world price, or when the extra production cannot be transported and sold, so that it returns low prices or actually perishes. Too many green revolution projects have failed in Africa because they were not profitable for farmers once the projects subsidies and transport support systems were withdrawn.
It will take massive investments to bring rural infrastructure and logistics up to the required levels in much of rural Africa. Work at IFPRI shows that it would take enormous amounts of investment in Africas rural infrastructure just to bring it up to the standards that India enjoyed in the 50s.4 One reason it is so costly is that Africa itself is huge and its population density is only a fraction of Asias. This great abundance of land is both a blessing and a curse. It is a blessing because it offers considerable potential for future growth. It is a curse because the per capita investment costs of establishing a good logistics support system are daunting - it would require an unbearable tax burden if rural Africans were expected to pay for this themselves. Frankly, it is hard to see how this problem can be solved any time soon. Relocating people within smaller areas has some economic appeal, but does not work in practice (e.g., Tanzania). New technologies in telecommunications and energy (e.g. internet, satellite phone systems, and solar/wind energy) may offer lower cost solutions to some types of infrastructure, but farmers still need roads, transport systems and markets to move and trade commodities.
There are some well-located irrigated and high-potential rainfed areas in Africa that have good access to markets and inputs, and where green revolution type technologies can be profitable and make an important contribution to national food security. However, much of rural Africa will need to look to lower-cost alternatives for meeting the food security needs of local people, at least for brought up to required levels. They will need improved natural resource management practices and technologies to harvest and conserve more water, to generate and recycle soil organic matter and plant nutrients, and low-input technological breakthroughs like drought-resistant crop varieties. Biotechnology may offer special opportunities to solve some of these problems, but only if the public sector undertakes or promotes the right kinds of research.
MANAGING ENVIRONMENTAL PROBLEMS ASSOCIATED WITH AGRICULTURE
As argued above, agricultural growth has a continuing and crucial role to play in alleviating poverty and food insecurity in Africa and Asia. However, much more needs to be done than in the past to ensure that this growth is not environmentally destructive.
It is useful to distinguish between two types of environmental problems associated with agriculture. On the one hand are the intensively irrigated and high-potential rainfed areas (the green revolution areas) where modern varieties and high levels of fertilizers and agro-chemicals are used. They are the breadbasket areas that feed the developing worlds burgeoning urban populations. The problems here largely relate to the excessive use and mis-management of fertilizers and pesticides that pollute waterways and upset ecosystems, irrigation practices that lead to salt build up and eventual abandonment of good farming lands, decline of groundwater levels, and loss of biodiversity. However, the high-yield gains achieved in these areas in recent decades have saved huge areas of forest and other environmentally valued or fragile lands that would otherwise have been converted to crop production.
On the other hand, an enormous amount of environmental degradation in rural areas has little to do with modern farming systems. A great deal of deforestation and land degradation (including soil erosion and soil fertility loss) has occurred in densely populated, less-favored areas that did not benefit from the modern farming revolution. This degradation is not driven by excessive intensification; quite the reverse, it is driven by insufficient agricultural intensification relative to population growth. As more and more people seek to eke out a living in these areas, they crop land in unsustainable and erosive ways, and fail to replenish the soil nutrients that they remove. The problem is aggravated by poor access to fertilizers that are key to maintaining yields and sustaining soil fertility. These two contrasting environments require very different solutions.
The management of intensive farming systems in irrigated and high-potential rainfed areas requires better management of modern inputs. Their current misuse is hardly surprising as millions of largely illiterate farmers have only recently begun to use them for the first time. The problem has been exacerbated by inadequate education and training, an absence of effective regulation of water quality, and input pricing and subsidy policies that made modern inputs too cheap and encouraged excessive use. Policy and institutional reforms that correct inappropriate incentives can and are making an important difference. Improved technologies, such as precision farming, ecological approaches to pest management, pest resistant varieties and improved water management practices can even increase yields while they reduce chemical use.1
market access and transport costs are daunting obstacles
to development... internet, satellite phone systems, and solar/wind energy may
offer lower cost solutions to some types of infrastructure, but farmers still
need roads, transport systems and markets to move and trade
In rich countries with abundant food supplies, the option exists of labeling foods produced as organic or ecologically friendly, and charging a price premium to offset their higher costs. The resulting price changes may not be unbearable for most people, and their governments could afford to subsidize food for the needy and farm incomes where needed. But taking this same approach in most African or Asian countries would be disastrous, aggravating poverty and malnutrition for hundreds of millions. These countries simply do not have the option of moving to farming systems that reduce total foodgrain output and raise food prices.
In many less-favored areas and a large part of Africa, the answer to much environmental degradation lies in the greater use of irrigation and modern inputs to achieve higher yields, matched with improved management of soil moisture and organic matter. Current input use is very low in these areas. For example, fertilizer use in Sub-Saharan Africa averages 11.6 kg of NPK nutrients per hectare of cropland compared to 158.4 kg in Europe and 265 kg in East Asia.5 Greater use could help restore soil fertility and increase yields without becoming an environmental threat. Unfortunately, because many less-favored areas have limited infrastructure and market access, greater use of modern inputs is difficult and often unprofitable, and farmers must find alternative ways to increase yields.
Ecological and low external-input farming approaches have important roles to play in these regions, at least until such time as infrastructure and markets are better developed. The greater labor intensity of these technologies is not necessarily a problem in many labor-abundant regions unless there is seasonal bunching of tasks. However, although desirable, allocating much land that would otherwise be in crop production to fallow, green manures, rotations and livestock may not be feasible for many small-scale farms, nor may the use of composts and manures for soil replenishment where these compete for more pressing household energy needs.
Although more skillful administration of traditional farming systems offers some promise for improved land management and for raising food production in many less-grass roots development agencies for their low external-input approaches are not substantiated by any rigorous testing with experimental controls. Nor is it clear that these successes work in larger areas of farmland, particularly in areas where poor soils and limited rainfall constrain possibilities for generating much organic matter without some use of inorganic fertilizers.
Pubic investment in agricultural research, rural infrastructure and human development is still fundamental for achieving food security in developing countries. However, these investments need to be targeted in ways that are more beneficial to the poor than in the past, and supported by policy and institutional reforms that improve incentives for the sustainable management of natural resources. In this context, it is disheartening to see that public investment in agriculture and rural areas is falling in many developing countries, a decline that is not being compensated for on any meaningful scale by private sector investment. Tight government budgets and donor fatigue are mostly to blame. It will not be easy to reverse this decline, and much more attention will need to be focused on doing more with less. This will need to involve better targeting of public investments and improved performance by the institutions that provide basic infrastructure services. These kinds of reforms could make a significant difference in compensating for reduced levels of public investment in Asia, but they will not be nearly enough to compensate for grossly inadequate levels of rural infrastructure in rural Africa.
1. Rosegrant M, Hazell P (2000) Transforming the Rural Asian Economy: The Unfinished Revolution. Oxford University Press for the Asian Development Bank, Hong Kong.
2. Brown LR (1995) Who Will Feed China?: Wake-up Call for a Small Planet. W. W. Norton & Company, New York.
3. Fan S, Hazell P, Haque T (2000) Targeting Public Investments by Agro-Ecological Zone to Achieve Growth and Poverty Alleviation Goals. Food Policy. 25 (4): 411-428.
4. Spencer D (1994) Infrastructure and Technology Constraints to Agricultural Development in the Humid and Subhumid Tropics of Africa. Environment and Technology Division Discussion Paper No. 4. International Food Policy Research Institute, Washington DC.
5. Wood S, Sabastian K, Scherr S (2000) Pilot Analysis of Global Ecosystems: Agroecosystems. A joint study by the International Food Policy Research Institute and the World Resources Institute, Washington DC.
Contact: Peter Hazell, Director, Environment and Production Technology Division, IFPRI, 2033 K Street NW, Washington DC 20006,
CLIMATE WILD CARD - WATER AND FOOD SECURITY
The buildup of carbon dioxide and other heat-trapping gases in the atmosphere confronts irrigated agriculture with the prospect of a changing climate. Like the joker in a game of cards, climate change has the potential to greatly alter the "game" of agriculture, but scientists do not know exactly how, when, or under what conditions this wild card will be played. They do know that Earth's temperature will rise, which in turn will intensify the global hydrological cycle. A warmer atmosphere will hold more moisture, increasing global rates of evaporation and precipitation by some 7-15%. Rainfall patterns will shift, with some areas getting more precipitation and some getting less. River flows will change. Hurricanes and monsoons are likely to intensify, and sea level will rise from thermal expansion of the oceans and the melting of mountain glaciers and polar ice caps. Although the major climate models agree fairly well on global-scale changes, they are not finely tuned enough to predict what will happen regionally and locally. This uncertainty makes it difficult to plan wisely for new dams, reservoirs, and irrigation systems that are supposed to last a half-century or more. Most disturbing, in cases where climate change results in less rainfall, areas already at or near water limits may move into a long period of shortages.
Many of the world's important irrigated areas depend on water from mountain snowmelt. These include much of the Indus and Ganges River basins in South Asia, the Aral Sea basin in Central Asia, the Colorado basin in the U.S. Southwest, and the Sacramento-San Joaquin valleys in California. Mountain snowpack acts like a reservoir, storing water in the winter and then releasing it during the spring and summer as the snows melt. The dams, reservoirs, and irrigation systems built in these regions are designed and operated with this pattern of river runoff in mind. These systems may be particularly at risk in a warmer world. With more precipitation falling as rain and less as snow, the volume of water stored naturally in mountain snowpacks will drop, and more winter precipitation will immediately become river flow. Moreover, the snowpack will melt earlier and faster, causing more risk of flooding in the spring and reducing the amount of water available just when irrigated agriculture needs it most - during the hot, dry summer.
As mountain glaciers shrink, large regions that rely on glacial runoff for water supply could experience severe shortages. The Quelccaya Ice Cap, the traditional water source for Lima, Peru, is now retreating by some 30 meters a year, up from only three meters a year before 1990, posing a threat to the city's ten million residents. And in northern India, a region already facing severe water scarcity, an estimated 500 million people depend on the tributaries of the glacier-fed Indus and Ganges rivers for irrigation and drinking water. But as the Himalayas melt, these rivers are expected to initially swell and then fall to dangerously low levels, particularly in summer. In 1999, the Indus reached record high levels because of glacial melt.
These "reservoirs in the sky," where nature stores fresh water for use in the summer as the snow melts, are shrinking and some could disappear entirely. This will affect the water supply for cities and for irrigation in areas dependent on snowmelt to feed rivers. If the mass of snow and ice in the Himalayas - which is the third largest in the world, after the Greenlandic and Antarctic ice sheets - continues to melt, it will affect the water supply of much of Asia. All of the region's major rivers - the Indus, Ganges, Mekong, Yang-tze, and Yellow - originate in the Himalayas. The melting in the Himalayas could alter the hydrology of several Asian countries, ncluding Pakistan, India, Bangladesh, Thailand, Viet Nam, and China. Less snowmelt in the summer dry season to feed rivers could exacerbate the hydrological poverty already affecting so many in the region.
John Schaake, a hydrologist with the U.S. National Weather Service, analyzed potential changes in the pattern of flow of the Animas River where it runs through Durango, Colorado. He found that a temperature increase of two degrees Celsius, with no change in precipitation, would have little effect on the total volume of annual runoff. The seasonal pattern of that runoff, however, would change greatly because of the reduced winter snowpack and its faster melting.
Schaake's model showed that, compared with current runoff patterns, average runoff in January through March would increase by 85%, while in the critical months of July through September it would fall by 40%. Without more reservoirs to store the increased winter/spring runoff, serious shortages would likely occur in summer - just the time when competition for water is keen for irrigation, for hydroelectricity, and to keep rivers flowing enough to sustain fisheries, dilute pollution, and support recreational activities. If, for the sake of illustration, similar kinds of altered river flows around the world necessitate a 20% increase in reservoir storage capacity, some $200-400 billion in new investment could be required just to sustain the current irrigated areas. Additional investment would be needed to expand irrigation systems to farming regions where rainfall becomes insufficient or too unreliable. In a warmer climate, increased evaporation in the spring would dry out the soil in some areas, leaving less moisture for e vaporation and local rainfall in the summer. If even two percent of existing rain-fed land worldwide requires irrigation to remain productive, the climate price tag could rise by another $120 billion - assuming today's average cost of irrigation projects. Future costs would be considerably higher.
Even if governments, international donors, and private investors could come up with such large sums, food security will likely be at risk for decades as planners, engineers, and farmers try to discern if the rainfall and runoff shifts that are occurring are long-term or temporary, and thus whether such investments are justified. Peter Gleick, of the California-based Pacific Institute, notes that "one of the most difficult climatic changes for most regions to handle would be increased variability - and thus more frequent extremes: higher peak floods, more persistent and severe droughts, greater uncertainty about the timing of the rainy reason. Few such changes would be beneficial."
There will, of course, be countervailing positive influences. Higher carbon dioxide levels in the air have a fertilizing effect on many crops, boosting rates of photosynthesis. They also cause plants to narrow the opening of their stomata, which reduces water consumption. Because these physiological changes can lead to higher crop yields and lower crop water use, they partly explain why some scientists find little cause for concern about climate change's impacts on agriculture. But for crops to benefit from the fertilizing effects of carbon dioxide, they must have sufficient soil moisture; otherwise, potential yield gains will quickly turn to losses. For example, a lack of soil moisture during the flowering, pollination, and grain-filling stages of growth is especially damaging to maize, wheat, soybean, and sorghum. If soils dry out in late spring and summer, and irrigation water is not available or sufficient to make up the deficits in soil moisture, harvests will suffer.
Some models that paint a fairly rosy picture about climate change's impacts on world agriculture fail to take into account this critical issue of water availability. In one study reported in the science journal Nature, for example, models assumed that "water supply for irrigation would be fully available at all locations under climate change conditions". In effect, the researchers assumed away a potentially big part of the problem.
Although no one can say precisely how irrigated agriculture will be affected by global warming, a few things are fairly certain. First, the future will not be a simple extrapolation of the past. Most water planning for the future, however, is necessarily based on past trends. Engineers are designing dams for the 21st century based on 20th century hydrology data, even though river flows may change considerably as the climate warms. Second, for some period of time, reservoir and irrigation systems are likely to be poorly matched to altered rainfall and runoff patterns. This may leave farmers short of water during the dry summer months. And third, if and when the needed adjustments are made, they will be costly.
The ironic flipside is that large-scale ice melt would also raise sea levels and flood coastal areas, currently home to about half the world's people. Over the past century, melting in ice caps and mountain glaciers has contributed on average about one-fifth of the estimated 10-25 cm global sea level rise. The rest caused by thermal expansion of the ocean as the Earth warmed.
During this century, the existing climate models indicate the sea level could rise by as much as one meter. If the Greenland ice sheet, which is up to 3.2 km thick in places, were to melt entirely, sea level would rise by seven meters. Even a much more modest rise would affect the low-lying river floodplains of Asia, where much of the region's rice is produced. According to World Bank analysis, a one meter rise in sea level would cost low-lying and already food insecure Bangladesh half its ric eland. Numerous low-lying island countries would have to be evacuated.
Excerpted from various Worldwatch Institute publications, including "Pillar of Sand: Can the Irrigation Miracle Last?" by Sandra Postel (WW Norton & Co., 1999)
Contact: Brian Halweil, Worldwatch Institute, 1776 Massachusetts Ave, NW, Washington, D.C. 20036, USA. Fax: 1-202 296 7365 or 1-202 833 0377, EMail: firstname.lastname@example.org Web: http://www.worldwatch.org
An ever-green revolution
The ACC/SCN-appointed Commission on the Nutrition Challenges of the 21st Century argued that a further revolution in agriculture will be required to adapt food production systems to growing needs and the changing environment. Key aspects of the new approach to food production to improve food security include:
· Increased investment in agricultural and natural resource management. The strengthening of agricultural research and extension systems will be vital. This runs counter to the substantial reduction in funding of agricultural research in the developed world where a crude link has been made between investment in agricultural research and the economic costs of all the food surpluses and export subsidies. The acknowledgement that developed countries will benefit from investing in tropical and subtropical agricultural research needs to be established along with much closer links to the needs and experience of small, local farmers.
Source: Commission on the Nutrition Challenges of the
21st Century (2000) Ending Malnutrition by 2020: an Agenda for Change
in the Millennium. Final Report to the ACC/SCN. ACC/SCN, Geneva.
MICRONUTRIENT DEFICIENCIES AND CONTAMINATION
Noel W. Solomons
Since the decade of the 90s, the public health community has turned away what was termed from protein-energy nutrition toward the paradigm of "hidden hunger", and to an interest in vitamin A deficiency, iodine deficiency disorders, and iron deficiency and its associated anemia. The implications for mortality and morbidity of micronutrient malnutrition states have spearheaded this renaissance of interest. Severe vitamin A deficiency leads to childhood blindness which is a death sentence in most deprived settings, but marginal vitamin A deficiency is associated with over 20% excess mortality from childhood diseases. Severe iodine deficiency is well known to produce cretinism, but it also contributes to foetal loss. Iron deficiency and anemia are associated with increased susceptibility to certain infections, and to decreased physical and mental performance. Severe gestational anemia has been associated with impaired pregnancy outcome and maternal mortality. Over the last ten years, a by-product of this focus on micronutrient malnutrition has been the emergence of interest in other micronutrient deficiencies of public health importance such as zinc, vitamin B12, folate, selenium and riboflavin.
A comprehensive framework for understanding the genesis of nutrient deficiencies was produced by Victor Herbert1 originally as five (but now as six) possible causal mechanisms. These are illustrated in Box 1. Although there is limited documented evidence relating environmental contamination to decreased absorption, utilization or destruction of nutrients, there is sufficient research to form a basis of inquiry.
Box 1: The six possible causes of all nutrient deficiency states
Source: modified after Herbert1
Box 2: Types of contaminants
global warming gases· Terrestrial
fungal toxins· pesticides/herbicides
Within the domain of direct biological interactions, it is prudent to begin with the effects of environmental contamination on non-human species, both plants and animals, that form part of the human food supply. This could have repercussions on the nutrition of the human population, especially that related to vitamins and minerals. Instances of pollution have differentially affected certain species. Petroleum spills have devastating consequences on marine mammals and birds. This has been recently demonstrated with the South African penguin. It has been estimated that the entire (endangered) population of the California sea otter would be extinguished by an oil spill over a particular range of the California coastline. The history of the thinning of egg shells of birds of prey due to the pesticide DDT which is concentrated in their food-chain is well documented. For those indigenous, hunter-gatherer groups that depend on wild fish and game for their diet, rich sources of micronutrients would be eliminated.
This interaction can reduce consumption of an important micronutrient source not only by killing off the species outright, but also by rendering it inedible. The detection of a high content of organic mercurial compounds in swordfish in the 70s is the classic example. An admonition against consuming this marine fish went out three decades ago. Although it has been shown that certain mineral-mineral interactions, specifically a selenium-mercury antagonism 2, mitigates the toxic consequences for the human consumer, concerns about the safety of swordfish persist to this day. High levels of environmental cadmium in the coastal fishery waters of Japan and Korea and its role in Itai-Itai disease have similarly produced reticence to consume fish and shellfish. 3 Shellfish are avoided when, as part of the "red tide" phenomenon, an algal toxin with often lethal respiratory paralysis effects is deposited in the plankton-feeding bivalves of coastal beds. Coastal crustacea are rich in zinc and other minerals, and avoiding them would reduce intakes in subgroups of the population.
The fear of environmental pollution can operate to adversely influence micronutrient status in one anecdotal, but plausible and unique situation. Inuit in the Hudson Bay and Baffin areas of northern Canada have become aware of the heavy metal and organic chemical pollution of their waters. Marine pollutants are concentrated up the food chain. The Inuit winter diet is based on large marine mammals (seals, narwhals) and fish which have high concentrations of these pollutants. There are instances where arctic mothers have refused to breastfeed because of fear of passing these contaminants from their milk to their infants (see p 18). Not being breastfed would have obvious impacts on the micronutrient status of infants and general health.
For plants, fungal contamination and fungal toxin formation, either with aflatoxin or fumonisins, represent an environmental hazard to human consumers. The toxin of the mold Aspergillus flavum has a special affinity for legumes and nuts. So strict are the tolerances of aflatoxin by the health authorities of the European Union, for instance, that ground nut importation is almost impossible. The fungus Fusarium moniliforme has a predilection for maize. The fumonisin toxins in corn in Africa is suspected to be part of the complex etiology of gastroe-sophageal cancers in the region.4
DIRECT INTERACTIONS OF ENVIRONMENTAL CONTAMINATION AND HUMAN MCRONUTRIENT NUTRITURE
Models of potential biological inter-relationships are outlined in Box 3. The first two examples of direct interactions between contamination and micronutrient status involve aggravant or synergistic relationships, in which one factor makes the other worse.
Box 3: Models of potential biological inter-relationships of micronutrient nutriture and environmental contamination
· Environmental contamination can produce or exacerbate a micronutrient deficiencyALLEVIATIVE (ANTAGONISTIC)
· Environmental contamination can prevent or alleviate a micronutrient deficiency
With respect to heavy metals, cadmium toxicity produces a nephropathy and the damaged kidneys become sieves for certain micronutrients. Zinc contamination from the environment into the food supply could produce a situation in which iron and copper nutrition would be affected in the exposed individuals, insofar as the absorption of high amounts of zinc produces an intestinal blockade to the passage of these trace metal nutrients. Both deficiency states lead to a microcytic anemia.
Conversely, that micronutrient deficiency can make one more susceptible to the effects of environmental contamination is illustrated by the classic case example of pollution-nutrition interaction, that of iron and lead.8 Plum-bism, a severe syndrome of lead intoxication, was known in the early industrial age when this metal was used for common implements. Milder forms of lead intoxication are known to cause cognitive impairment in children and has recently been implicated in hypertension in lead-exposed women.9 Iron absorption is regulated by the iron reserves of the host. When iron status is adequate or excessive, its absorption is down-regulated. The uptake of ingested lead, from lead-based paint, from fuel exhaust, or from pottery glaze, is similarly blocked by a common cellular mechanism of absorptive regulation. Good iron status protects against lead toxicity in a lead-ridden environment. Conversely, iron deficiency, which affects 40% of preschool children in developing countries produces an avid capture of dietary iron through up-regulation of its transport. The same co-adaptation mechanism works in these populations to enhance the uptake of environmental lead through the gut.
Antagonistic relationships: A third variant would be environmental contamination preventing or alleviating a micronutrient deficiency. One could imagine that metallurgical mining could be initiated in areas in which the human populations and fauna were deficient in one or another trace element. For instance, a de novo release into the soil or water of selenium or zinc from mining or manufacturing activities could have the transient effect of resolving low micronutrient status in the human, livestock and wildlife populations, while continued exposure would lead to toxicities.
For the fourth variant of the interaction, namely that of micronutrient deficiency making an individual more resistant to the effects of environmental contamination, there are no obvious or confirmed examples. A series of theoretical postulates, worthy of investigation can be advanced, however. Such a postulate would involve iron, iron deficiency, and contaminants that act as oxidants or promoters of in vivo free-radical generation. Ionizing radiation and several organic substances initiate cellular oxidation. In theory, the richer the intracellular pool of iron, the more sustained and vigorous might be the oxidation. Ironically, iron deficiency may be protective against the effects of oxidizing contaminants in the environment.
UNINTENDED CONTAMINATING CONSEQUENCES OF PUBLIC HEALTH MEASURES TO PREVENT OR CORRECT HUMAN MICRONUTRIENT MALNUTRITION
Public health authorities have the responsibility to alleviate endemic micronutrient deficiencies. Unfortunately, some of the same social and economic forces that promote micro-nutrient malnutrition also stand in the way of public and private actions against it. Nonetheless, an armamentarium of four modalities to combat endemic deficiencies, used alone or in combination, have been outlined.10 These include: 1) nutrient supplementation; 2) nutrient fortification; 3) food-based measures to improve natural food content and diversity of diet toward increased consumption of micronutrient rich sources; and 4) general health measures to improve nutrient absorption or reduce loss. Hence, our final consideration is of direct or indirect measures to alleviate public health problems that could theoretically produce situations of environmental contamination. A micronutrient fortification or supplementation scheme might contaminate. Promotion of cultivation or livestock or fishery development to improve human micronutrient status could also lead to pollution of the environment. Some examples are illustrative:
Fluoridation of water supplies is implemented to combat dental caries. Fluorosis is a potential consequence of an intervention designed to protect micronutrient status. Transient iodine excess in the form of thyrotoxicosis, or the so-called jodbasedow phenomenon, is well documented in iodine-deficient areas when salt or bread fortification with iodine is supplemented rapidly in a population with long-standing IDD.11 Experience from goitrous areas of China where iodine-containing fertilizers were used poses another example of micronutrient improvement combined with a risk of environmental over-shoot. The "seeding" of the hyposeleniferous Finnish soils with selenium fertilizer is, to date, a success story in improving the selenium status of plants, livestock and the human population,12 but it was curtailed after a few years of application, because of rapid selenium renewal in the environment.
Modern agriculture is based on the use of a series of chemicals some of which are potentially-contaminating substances for the environment. Iodine antiseptic is applied to the udders of dairy cattle to prevent bovine mastitis. This is one example, there are many more. Ironically, the equally disquieting scenario of genetically-modified crops, responds in part to chemical contamination by reducing the need for herbicides and pesticides to maintain high crop yields. In some settings dietary diversification will include the promotion of micronutrient-rich foods of animal origin. Intensive livestock production, itself, is an environmental hazard, as shown by the methane-loaded and ammonium saturated low areas of the Netherlands (see p 29). There is an environmental cost to putting meat on the table. Having organ meats such as liver and kidney on the menu is even more interesting. These are the richest sources of vitamins and minerals, but they also contain concentrated environmental toxins.
POLICY AND PROGRAMMATIC CONSIDERATIONS
It may be considered suspiciously self-serving that a nutrition investigator would conclude that research - and a standing of micronutrient malnutrition and the environment. Evidence outside the arch-classic examples is scant. One would have to move a research agenda forward in order that nutrition policies and programs could be influenced and guided by scientifically sound and biological principles. The same uncertainty as to the causality in relationships of the synergistic type, however, renders the use of micronutrient status monitoring, as an adjunct to surveillance of environmental contamination, premature at best.
The lasting impact of this issue of the SCN News perhaps will be to open some eyes - and some channels - regarding the links between and among the toxicological, nutritional and agricultural domains. Some of the evidence presented here could help forge multidisciplinary perspectives to the, as yet, unasked and certainly unanswered queries about the interface of micro-nutrients and environmental contamination in this ever more crowded, public health-challenged global community.
1. Herbert V (1973) The five possible causes of all nutrient deficiency: Illustrated by deficiencies of vitamin B12 and folic acid. American Journal of Clinical Nutrition 26:77-88.
2. Whanger PD (1985) Metabolic interactions of selenium with cadmium, mercury and silver. Advances in Nutrition Research 7:221-250.
3. Nomayama K, Nomiyama H (1998) Cadmium-induced renal dysfunction: new mechanism, treatment and prevention. Journal of Trace Elements in Experimental Medicine 11: 275-288.
4. Riley RY, Morred WP, Bacon CW (1993) Fungal toxins in foods: recent concerns. Annual Reviews in Nutrition 13:167-189.
5. Beisel WR (1975) Metabolic response to infection. Annual Reviews of Medicine 26:9-20.
6. Rosenberg IH, Solomons NW, Schneider RE (1997) Malabsorption associated with diarrhea and intestinal infections. American Journal of Clinical Nutrition 30:1248-1253.
7. Ruz M, Solomons NW (1990) Mineral excretion during acute, dehydrating diarrhea treated with oral rehydration therapy. Pediatric Research 27:175-180.
8. Watson WS, Hume R, Moore MR (1980) Absorption of lead and iron. Lancet 2: 236-237.
9. Houston DK, Johnson MA (2000) Lead as a risk factor for hypertension in women. Nutrition Reviews 57:277-279.
10. Underwood BA (1998) Micronutrient malnutrition. Is it being eliminated? Nutrition Today 33:121-129.
11. Connolly RJ, Vidor GI, Stewart JC (1970) Increase in thyrotoxicosis in endemic goitre area after iodation of bread. Lancet 1:500-502
12. Makela AL, Wang WC, Hamalainen M et al. (1995) Environmental effects of nationwide selenium fertilization in Finland. Biological Trace Element Research 47:289-298.
Contact: Noel W. Solomons, CeSSIAM-in-Guatemala, P O Box 02-5339, Section 3163 Guatemala, Miami FL 33102-5339, USA. Fax: + 5024 733 942
Women and the Domestic Environment
In many developing countries, women are responsible not only for cooking and performing most of the domestic work that sustains the family but they are also responsible for growing food crops, fetching water and gathering fuel. However, when food is inadequate women are often more affected than men due to their lower status in many societies and higher energy needs as a result of their physical work. As a consequence they often suffer more malnutrition resulting in lower immunity and greater susceptibility to infection. Food security at the household level could be improved through:
· Practising sustainable agriculture. This ensures enough food is produced without causing land degradation. It includes rotating crops, leaving land fallow, proper stocking density, reducing use of chemicals, reducing soil erosion.
Contact: H.N.B. Gopalan, Task Manager (Environmental
Health), Policy Analysis, Review and Development Unit, Division of Environmental
Policy Development and Law, United Nations Environment Programme (UNEP),P.O. Box
30552, Nairobi, Kenya. Tel: (254-2) 623246, Fax: (254-2) 623861, EMail
email@example.com Web: www.unep.org
PERSISTENT ENVIRONMENTAL CONTAMINANTS AND BREASTFEEDING
Harriet V. Kuhnlein
Concern for contaminants in breastmilk has to be one of the most pressing issues in environmental protection. It gives clarity and imperative to the need for interdisciplinary research, contaminant emission controls, and sound public health advice. In this issue of the SCN News, a perspective on organochlorine and heavy metal contaminants that affect populations focuses on the quality of breastmilk and the health of infants.
ORIGIN OF CONTAMINANTS
Persistent contaminants are those that do not easily bio-degrade and disappear once they are released into the environment, and therefore they insidiously accumulate over time in the environment and in people. Persistent contaminants include organochlorines such as PCBs, di-oxins, DDT, and HCH, as well as heavy metals such as mercury, lead and cadmium. All have been introduced into the environment by large industries beginning in the 40s and 50s. Heavy metals are naturally present in the earths crust, but during this century their entry into biological species has been accelerated. When present in the natural environment, contaminants accumulate in food species and move up food chains, with organochlorines accumulating in fat tissues and heavy metals (particularly mercury) accumulating in muscle, organ and other meat or skin tissues. These contaminants are present worldwide as a result of long-range transport in air and ocean currents following release at industrial sites, or in the near environment of local industries, such as mining and pulp processing plants.1 They accumulate in human tissues and are released in breast-milk. Recent concern for the use of mercury in dental amalgam has also prompted public health concern for breastmilk mercury levels.2
Box 1: Chemical identities of five persistent
A mixture of polychlorinated dibenzo
A mixture of chlorinated camphenes
TOLERANCES FOR LEVELS OF CONTAMINANTS IN BREASTMILK
Estimates of exposure to contaminants through breast-milk must obviously take into account the types and concentrations of the residues in the milk as well as the amount of milk consumed. The concern for contaminants in breastmilk relates to the fact that there is little dietary diversity, if any at all, for most infants in the early months after birth. Further, tolerances are often set based on animal toxicology experiments that are then extrapolated to adult body weight. Additional extrapolation to infant body weight may disregard potential quantitative differences in sensitivity. In other words, with respect to potential contaminant toxicity and establishment of tolerance levels, infants are not just small adults, but there is no consistent way to estimate the differences.6
Organochlorines are expressed as units based on fat content of the milk (mg or pg/g milk fat) or as whole milk, assuming a milk fat concentration of 3.5%. Mercury is the only heavy metal that has been recognized to accumulate in the food chain to the extent that potential risk from milk to the breastfed infant is considered. Mercury tolerances are based on ng/ml whole milk and may be expressed as total, organic or inorganic mercury7,2. However, established guidelines for dietary intake express contaminants in units per kg body weight per day (mg/kg bw/d), which for infants depends on the extent of breastmilk consumption and body weight, which are not often reported in population studies. Box 2 presents some of the established dietary guideline levels for contaminants in food, which are sometimes also applied to breastmilk. A caveat to these guidelines is that each is established through toxicological testing and consideration of one contaminant at a time, when natural food sources, such as breastmilk, of affected populations usually contain multiple contaminants. Unfortunately there has been little research on this real-life circumstance, and the effects of multiple simultaneous contaminants are mostly unknown.6 The US Agency for Toxic Substances and Disease Registry has recently reviewed pesticide exposure through breastmilk, and describes the establishment of minimum risk levels (MRLs) for each contaminant in breastmilk that can be used for screening purposes. It is emphasized that MRLs are deliberately conservative with several safety factors, and are not suitable for food regulatory purposes. For breastmilk, MRLs are based on an average daily intake of 700 ml of milk and 24 g of milk fat. For example, an MRL for DDT is 0.0025 mg, based on these calculations for a 5 kg infant.8 This is in stark contrast to the food regulation guideline for DDT found in Box 2.
Box 2: Canadian Food Guideline levels of six
persistent contaminants - per 100g
Concentrations of total DDT, PCBs, and dioxins in nonrepresentative samples from various nations have been reviewed by UNICEF 7 and Polh and Tylenda. 8 It was noted that whole breastmilk from industrialized countries has higher concentrations of PCBs (15-40 mg/g) and di-oxins (0.2-0.6 pg/g), whereas developing countries have higher concentrations of chlorinated pesticides, such as DDT and metabolites (0-300 mg/g) and HCH (up to 0.084 mg/l whole milk).
Breastmilk samples in Kazakhstan were found to have high levels of the dioxin congener TCDD (6.2-118.2 pg/g fat), HCH, and DDT, all thought to emanate from localized sources.9 Total toxaphene was found to be significantly higher in recent samples of breastmilk from the Keewatin district of Nunavut, Canada (mean 67.7 ng/g fat) compared to Southern Canada in two time periods (6.03 and 12.1 ng/g fat). Dioxins in the Keewatin samples had the mean sum of toxic equivalents (TEQ) of 6.5, whereas the Eastern Arctic Inuit in Nunavik had 34.2, as assessed in 1990.10 In Brazil, total mercury in breastmilk of mothers in gold mining districts of the Amazon basin ranged from 0.0 to 24.8 ng/g whole milk (mean at 5.85 +/- 5.9 SD).11 These breastmilk levels of dioxins, toxaphenes and total mercury are among the highest reported to date from natural food resources. In comparison, Iraqi women who consumed methylmercury-contaminanted bread made from agriculturally treated seed in the early 70s had peak milk mercury levels of 200 ng/g7.
While breastmilk may be considered the main or only exposure vehicle of infants who are breastfed, dietary exposure of women is more complex. To be considered are the multiple food sources of contaminants, the levels of contaminants in each, as well as the extent of consumption. Although fish is considered the main natural source of mercury for most populations at risk, several sea mammals also contribute high mercury levels to dietary mercury of some groups. Several species, particularly high food-chain mammals, can provide varying amounts of total dietary levels of a variety of organochlorines and heavy metals, depending on the extent of consumption. 5,12
Concern for dental amalgams that release inorganic mercury has been investigated in Sweden 2 and Germany.13 Maternal dental amalgam mercury was found in breast-milk, however dietary mercury particularly from fish was a confounding variable. In the German study, maternal dental amalgams were considered of minor importance in comparison to maternal dietary mercury exposure for breastfed infants.
Thus, persistent environmental contaminants are indeed found in breastmilk and maternal diets. In fact, multiple contaminants are present and are contributed from a variety of maternal food sources of natural origin as well as dental amalgam. However, considerable research has documented that it is fetal rather than lactational exposure that contributes the major sources of organochlorines and mercury to the infant.14 Dietary exposure of women through the childbearing years, perhaps the entire life term until parturition, seems to be the primary contribution to contaminant levels in the fetus and infant.
Nevertheless, breastmilk worldwide remains as source of contaminants to infants.
INADEQUATE ASSESSMENT OF LONG-TERM EFFECTS
There is clearly a need for more research not only for continued monitoring of breastmilk levels, but for the effects of exposure of contaminants to the fetus and infant through breastmilk and other introduced food. Importantly, the possible toxicological interactions of multiple contaminants introduced through breastmilk, and the possible interaction of nutrients and contaminants in this important food need to be studied. The effects of lifetime accumulation and multigeneration studies need to be established, as do studies on variable effects from levels in primiparous births in contrast to those born later to the same woman.15
It is still recognized that the known benefits of breastfeeding outweigh the largely unknown risks of contaminants present in breastmilk
Maternal milk as a source of nutrients and immunity for the infant has been widely known for decades. In non-industrialized countries breast-feeding confers a greater likelihood of survival from diarrhea and respiratory infections, and in industrialized countries breastfeeding reduces the number of episodes from ear infection, diarrhea, and other chronic disease. Furthermore, breastfeeding confers a measure of protection for women from ovarian cancer or premenopausal breast cancer.7
As persistent contaminants continue to accummulate worldwide, there are pressing needs for policies and action to deal with this crisis. Most importantly, the body of evidence for fetal and infant exposure to organochlorines and heavy metals gives imperative for international actions to stop emissions globally such as those undertaken by the United Nations Environmental Program.16
1. AMAP (1999) Assessment Report: Arctic Pollution Issues. Arctic Monitoring and Assessment Program. Oslo, Norway, 859 pp.
2. Oskarsson A, Schhtz A, Skerfving S et al. (1996) Total and inorganic mercury in breast milk and blood in relation to fish consumption and amalgam fillings in lactating women. Archives of Environmental Health 51(3):234-241.
3. Commoner B, Bartlett PW, Eisl H et al. (2000) Long-range air transport of dioxins from North American sources to ecologically vulnerable receptors in Nunavut, Arctic Canada. Center for Biology of Natural Systems (CBNS), Queens College, City University of New York. Report to the North American Commission for Environmental Cooperation. http://www.cec.org
4. Watt-Cloutier S, Quassa P (2000) Canadian Inuit call upon the United States to stop polluting the Arctic. Press Release issued by Inuit Circumpolar Conference, Canada. October 3, 2000.
5. Kuhnlein HV, Receveur O, Muir DC et al. (1995) Arctic indigenous women consume greater than acceptable levels of organochlorines. Journal of Nutrition. 125 (10):2501-10.
6. NRC (1993) Pesticides in the Diets of Infants and Young Children. National Research Council. National Academy Press. Washington, D.C.
7. UNICEF (1997) Breastfeeding and environmental contamination. A discussion paper. New York: UNICEF Nutrition Section, 12 pp.
8. Pohl HR, Tylenda CA (2000) Breast-feeding exposure of infants to selected pesticides: a public health viewpoint. Toxicology and Industrial Health 16:65-77.
9. Lutter C, Iyengar V, Barnes R et al. (1998) Breast milk contamination in Kazakhstan: implications for infant feeding. Chemosphere 37 (9-12): 1761-72.
10. Newsome WH, Ryan JJ (1999) Toxaphene and other chlorinated compounds in human milk from Northern and Southern Canada: A comparison. Chemosphere 39 (3): 519-526.
11. Barbosa AC, D\rea JG (1998) Indices of mercury contamination during breast feeding in the Amazon Basin. Environmental Toxicology and Pharmacology 6:71-79.
12. Kuhnlein HV, Chan HM (2000) Env iron-ment and contaminants in traditional food systems of northern Indigenous Peoples. An nual Review of Nutrition 20:595-626.
13. Drexler H, Schaller KH (1998) The mercury concentration in beast milk resulting from amalgam fillings and dietary habits. Environmental Research 77(2):124-9.
14. Joint Working Group (1998) Nutrition for Healthy Term Infants. Canadian Paediatric Society, Dietitians of Canada and Health Canada. Minister of Public Works and Gov ernment Services, Ottawa.
15. Feeley MM, Jordan SA, and Gilman AP (1998) The Health Canada Great Lakes Multi-generation Study - Summary and regulatory considerations. Regulatory Toxocology and Pharmacology 27:S90-S98.
16. Stone D (1999) Facilitation of international action related to long-range transport of contaminants into the Arctic. In: Kalhok, S (Ed.) Synopsis of Research Conducted Under the 1998/99 Northern Contaminants Program. Minister of Indian Affairs and Northern Development. Ottawa.
Special thanks to Laurie Chan, Donna Mergler and other staff in the Centre for Indigenous Peoples Nutrition and Environment (CINE) at McGill University.
Contact: Harriet V Kuhnlein, Professor of Human Nutrition, McGill University, Macdonald Campus, Founding Director, Centre for Indigenous Peoples' Nutrition and Environment (CINE), 21, 111 Lakeshore, St Anne de Bellevue, Quebec H9X 3V9, Canada. Fax: +1 (514) 398 1020 EMail: firstname.lastname@example.org Web: http://www.cine.mcgill.ca
COMMUNICATING ABOUT RISKS AND INFANT FEEDING
Penny Van Esterik
Breastfeeding advocates have a responsibility to examine and critique the continuously accumulating evidence concerning breastfeeding and environmental toxins, and how this information is communicated to policy makers, advocacy groups, and the general public. Because of the widespread pollution of rural and urban environments, toxic substances such as PCBs, dioxins, phthalates, and heavy metals have been found in samples of breastmilk. We hear so much about toxins in breastmilk because breastmilk is a medium that is convenient and cheap to test and not because it is necessarily more toxic than blood or body fat.
Advocacy groups supporting breastfeeding have worked to
contain the damage done by reports on contaminated breastmilk by publicizing the
contamination of water and other foods
Bottle feeding also takes place in a polluted environment using an industrially produced product subject to contamination and accidents. Infant formula is usually reconstituted using tap or surface water, which may contain toxins and diarrhoea-causing pathogens. Hormone-disrupting chemicals such as phthalates, nonylphenols, and bisphenol-A have been found in plastic feeding bottles. Therefore, we should be aware that whatever needs to be examined about breastfeeding should be examined about alternatives to breastfeeding as well.
Breastfeeding as a media subject is both sexy and emotional. It is an irresistible topic because every story has the potential to be sensational and controversial. The emotional ambivalence about breastfeeding expressed by many individuals and groups heightens the drama of stories. In the case of environmental pollution and toxins in breastmilk, there are both contradictory messages from the experts as well as differences in interpretation by the media. Breastfeeding advocates are vulnerable if they ignore potential risks associated with breastfeeding. They are also at times defensive, for they speak on behalf of a product - breastmilk - with no commercial endorsement, and on behalf of a life-sustaining process - breastfeeding. Advocates may react with appropriate (or in the case of emotional overreaction, perhaps inappropriate) responses that will make a media splash, creating an even more sensational story. Breastfeeding mothers may overreact to perceived threats to breastfeeding because they are so intimately bound up in the protection of their breastfed infants.
Advocacy groups supporting breastfeeding have worked to contain the damage done by reports on contaminated breastmilk by publicizing the contamination of water and other foods. When the New York Times accused breastfeeding advocates of suppressing "scientific evidence" about HIV/AIDS transmission through breastmilk, infant formula manufacturers offered to sell infant formula to agencies in affected countries. In this way, they redeem themselves in the public eye, for their aggressive promotion of their products in those same countries that now accept their offers of subsidized infant formula. Because of the political implications of all these messages, communicators must walk the fine line between "scare tactics" and "suppressing the evidence". Neither toxins in breastmilk nor HIV/AIDS and breastmilk are amenable to the 30 second sound bite required by many media sources.
Breastfeeding is one point of entry for talking about the much broader questions of contamination, pollution, and environmental health. But there are often serious discrepancies in the way environmental pollution and breastfeeding are thought and talked about by environmentalists and breastfeeding advocates. The environmental literature speaks of breastmilk as a warning system for environmental exposure. But breastfeeding advocates speak of breastmilk as total nutrition for an infant from birth to six months. Breastfeeding advocates stress that breastfeeding provides some protection from breast cancer while environmental groups point out the substances in breastmilk that are carcinogenic. Environmentalists accuse breastfeeding advocates of burying their head in the sand and suppressing information critical of breastfeeding. Headlines about polluted mother's milk signify ultimate sacrilege, but they seldom suggest solutions. Evidence of pollutants in breastmilk tells us about serious environmental problems for children. It does not, however, tell us about serious environmental problems caused by breastfeeding. For example, it is not known how exposure to toxins affects formula-fed infants, breastfed infants, and adults.1 If breastfeeding in a contaminated world were all that dangerous, one would expect to see increased incidence of cancers among people who were breastfed. In fact, breast-feeding may even mitigate affects of prenatal toxic exposure.
breastfeeding may even mitigate affects of prenatal toxic
Industries demand ´proof of harm before agreeing to regulation, but often ´scientific levels of proof are not available. Environmental groups should not have to prove that pollutants are hazardous before protective legislation can be put in place; mothers should not have to prove that their breastmilk is safe. How did the burden of proof shift from corporations and governments that allow contamination, to breastfeeding mothers who worry that they should have their breastmilk tested for contaminants?
A number of breastfeeding advocacy groups, including LaLeche League, IBFAN and WABA, have produced brochures for public education on this issue. The WABA folder, Breastfeeding: Natures Way,2 argued in general terms that breastfeeding is natural, sustainable, and nonpolluting. It included examples of how the production of infant formula has proved vulnerable to contamination by bacteria, radioactivity, chemicals and foreign bodies, listing specific recalls and accidents. Referring to the fact that PCBs and other pollutants have been found in some samples of cow milk and breastmilk, it pointed out that WHO concluded that the advantages of breastmilk far outweigh any possible risks. Finally, it reassures the reader by pointing out that levels of toxins found in breastmilk fell by around 35% in Europe between 1988 and 1994.
Coalition building among environmental groups, breastfeeding advocates and womens health activists is necessary. These groups are co-travellers who must work together to advocate for social change. Cooperation amongst the groups might involve the following principles:
· acknowledge what is known about contaminants in breastmilkReaching a consensus about contaminants and breastfeeding will not be easy. Acting and communicating in the face of scientific uncertainty and highly charged emotions is particularly challenging. But most would probably agree with the policy: Health professionals advise that the known benefits of breastfeeding outweigh the potential risk of exposing infants to PCBs in human milk.3
· stress prenatal exposure as contributing to the body burden of all babies, not just breastfed babies
· identify the source of the pollution (chemical industries), not the source of evidence (breastmilk)
· stress the risks associated with artificial breastmilk substitutes and the risks of not breastfeeding when communicating about contaminants in breastmilk
· draw attention to alternatives to toxic products, not alternatives to breastmilk
· avoid metaphors of downloading toxins from one body to another
· avoid pump and dump as a solution to conc ern about breastmilk
· make clear in media reports that any testing of breast-milk is done for bio-monitoring programs, not for advising individual mothers on the condition of their breast-milk
· draw attention to contaminated milk, not contaminated mothers
· suggest practical actions to reduce contaminant loads, such as limiting consumption of fatty meats and dairy products
1. Jensen A, Slorach S (1991) Chemical Contaminants in Human Milk. CRC Press, Inc. Boca Raton.
2. WABA (1997) Breastfeeding: Nature's Way. '97 Action Folder
3. Guidotti T, Gosselin P eds. (1999) The Canadian Guide to Health and Environment. Edmonton: University of Alberta Press.
Funding for Penny Van Esteriks paper was provided by the National Network on Environments and Womens Health (NNEWH), supported by the Centres of Excellence for Womens Health Program, Womens Health Bureau, Health Canada. The views expressed herein do not necessarily represent the official policy of Health Canada.
An expanded version of this paper is available from WABA http://www.waba.org.br/or EMail: email@example.com
Contact: Penny Van Esterik, Anthropology, Vari Hall, York University, 4700 Keele St., Toronto, ON, Canada M3J 1P3 EMail: firstname.lastname@example.org
IBFAN GUIDELINE STATEMENT ON BREASTFEEDING AND DIOXINS
In recent weeks there have been an increasing number of reports in the press about the problems caused by dioxins. Dioxins are produced during various industrial processes, particularly during burning and incineration. They are environmental contaminants and are found mainly in the food chain where they are absorbed by humans. Dioxins are stored in body fat and are extremely persistent. Absorption takes place mainly through the food we eat (90-95%) but also through the air we breathe (5-10%). Breastmilk is often cited as a source of dioxins, but this is because fat soluble contaminants are relatively easily measured in breastmilk, not because breastmilk is any more contaminated than other body parts.
A recent review noted that studies have shown that the effects of dioxin contamination were associated with exposure via the placenta rather than via breastmilk. In areas of high contamination levels due to industrial processes or accidents, the available scientific literature indicates that a high level of dioxin contamination during pregnancy can lead to the impairment of child growth and development. Importantly however, it was concluded that breastfeeding, even in a contaminated environment, has a positive impact on the development of children as compared to those artificially fed.1
As a result of these findings, a number of countries have advocated that breastfeeding should continue to be "encouraged and promoted on the basis of convincing evidence of its benefits to the overall health and development of the infant".2
The International Baby Food Action Network (IBFAN) agrees with this recommendation and further recommends that the debate about dioxin contamination should not unduly influence a mother's decision to breastfeed.
· breastmilk provides optimal, unique and perfectly balanced nutrition for a babyIBFAN urgently calls upon decision makers in industry and politics to adopt environmentally-friendly initiatives in production and waste-disposal, to promote political awareness of ecological dangers, and to create the appropriate legal framework to prevent the harmful contamination of our environment, and to protect the health of our children, both present and future generations.
1. Van Leeuwen FX R, Younes MM (2000) Assessment of the health risks of dioxins: re-evaluation of the tolerable daily intake (TDI), Food Additives and Contaminants 17(4).
2. Ministry of Agriculture, Food and Fisheries (1996) Dioxins in human milk, Food Surveillance Information Sheet, UK
We would like to express our thanks to the toxicologists of the International Programme on Chemical Safety at the World Health Organisation for their valuable comments on this statement.
This statement was developed by the IBFAN working group on Contaminants in Baby Foods in response to media scares on this issue. It was reviewed by members of the IBFAN Co-ordinating Council in November 2000. This statement is intended as a guideline to assist IBFAN groups in preparing a response to press reports and will be shared with other concerned NGOs.
Contact: Alison Linnecar, International Baby Food Action
Network (IBFAN), EMail: email@example.com Web:
Governments Finalize Persistent Organic Pollutants Treaty
Johannesburg, 10 December 2000
Diplomats from 122 countries have finalized the text of a legally binding treaty that will require governments to minimize and eliminate some of the most toxic chemicals ever created. "Persistent organic pollutants (POPs) threaten the health and well-being of humans and wildlife in every region of the world", said John Buccini, the Canadian government official who chaired the talks. "This new treaty will protect present and future generations from the cancers, birth defects, and other tragedies caused by POPs."
Executive Director Klaus Töpfer of the United Nations Environment Programme, which organized the negotiations, applauded the strong international regime that has been established for promoting global action on POPs. "This is a sound and effective treaty that can be updated and expanded over the coming decades to maintain the best possible protection against POPs", he said.
The treaty sets out control measures covering the production, import, export, disposal, and use of POPs. Governments are to promote the best available technologies and practices for replacing existing POPs while preventing the development of new POPs. They will draw up national legislation and develop action plans for carrying out their commitments.
The control measures will apply to an initial list of 12 chemicals which include eight pesticides (aldrin, chlordane, DDT, dieldrin, endrin, heptachlor, mirex, and toxaphene), two industrial chemicals (PCBs and hexachlorobenzene, which is also a pesticide), and two unwanted by-products of combustion and industrial processes (dioxins and furans). A POPs Review Committee will consider additional candidates for the POPs list on a regular basis. This will ensure that the treaty remains dynamic and responsive to new scientific findings.
A financial "mechanism" will help developing countries and countries with economies in transition meet their obligations to minimize and eliminate POPs. "New and additional" funding and technical assistance will be provided. Most of the 12 chemicals are subject to an immediate ban. However, a health-related exemption has been granted for DDT, which is still needed in many countries to control malarial mosquitoes. This will permit governments to protect their citizens from malaria - a major killer in many tropical regions - until they are able to replace DDT with chemical and non-chemical alternatives that are cost-effective and environmentally friendly.
Similarly, in the case of PCBs, which have been widely used in electrical transformers and other equipment, governments may maintain existing equipment in a way that prevents leaks until 2025 to give them time to arrange for PCB - free replacements. Although PCBs are no longer produced, hundreds of thousands of tons are still in use in such equipment. In addition, a number of country-specific and time - limited exemptions have been agreed for other chemicals.
Governments agree to reduce releases of furans and dioxins, which are accidental by-products and thus more difficult to control, "with the goal of their continuing minimization and, where feasible, ultimate elimination". Other national measures required under the treaty relate to reporting, research, development, monitoring, public information and education.
The meeting in Johannesburg was the fifth and final POPs negotiating session and was attended by some 600 participants. The treaty will be formally adopted and signed by ministers and other plenipotentiaries at a Diplomatic Conference in Stockholm on 22 - 23 May 2001. Governments must then ratify, and when 50 have done so the treaty will enter into force. This process normally takes several years.
Of all the pollutants released into the environment every year by human activity, POPs are among the most dangerous. They are highly toxic, causing an array of adverse effects, notably death, disease, and birth defects, among humans and animals. Specific effects can include cancer, allergies and hypersensitivity, damage to the central and peripheral nervous systems, reproductive disorders, and disruption of the immune system.
These highly stable compounds can last for years or decades before breaking down. They circulate globally through a process known as the "grasshopper effect". POPs released in one part of the world can, through a repeated (and often seasonal) process of evaporation - deposit, evaporation - deposit, be transported through the atmosphere to regions far away from the original source.
In addition, POPs concentrate in living organisms through another process called bio-accumulation. Though not soluble in water, POPs are readily absorbed in fatty tissue, where concentrations can become magnified by up to 70,000 times the background levels. Fish, predatory birds, mammals, and humans are high up the food chain and so absorb the greatest concentrations. When they travel, the POPs travel with them. As a result of these two processes, POPs can be found in people and animals living in regions such as the Arctic, thousands of kilometers from any major POPs source.
Fortunately, there are alternatives to most POPs. The problem is that high costs, a lack of public awareness, and the absence of appropriate infrastructure and technology often prevent their adoption. Solutions must be tailored to the specific properties and uses of each chemical, as well as to each country's climatic and socio-economic conditions.
Contact: Michael Williams: Telephone: 41-22-917-8242,
EMail: Michael.firstname.lastname@example.org Web: www.chem.unep.ch/pops/
NUTRITION FOR SUSTAINABLE ENVIRONMENTS
Timothy Johns and Pablo B. Eyzaguirre
The merging of community development priorities with those of environmental conservation brings with it recognition that unless human populations meet their basic survival needs they cannot afford to conserve. At the same time, unless local communities protect the environments around them they have limited hope to thrive beyond the short term. As nutrition represents the most fundamental of human needs it provides a useful perspective from which to consider this paradox.
Global fora have acknowledged in broad terms that integrity of the environment and meeting basic human needs are interconnected (see: World Declaration on Nutrition1, International Conference on Nutrition2, Convention on Biodiversity3, Global Plan of Action for the Conservation and Sustainable Utilization of Plant Genetic Resources for Food and Agriculture.4 Unless environments are used in sustainable ways, it will become progressively more difficult to feed the worlds population.
...unless human populations meet their basic survival
needs they cannot afford to conserve
TRADITIONAL FOOD SYSTEMS
From an evolutionary perspective, organisms are adapted to a particular environment when they are able to meet their biological needs. Throughout their history as a species, humans developed specific modes of subsistence to diverse environments ranging from the equator to polar regions, from sea level to elevations exceeding 4000 meters, and from humid rainforests to hot deserts. The unique features of many of these environmental relationships as they involve satisfying nutritional needs have been documented among extant populations with traditional lifestyles,5,6 often populations identified as indigenous. The nutrient complimentarity of Meso-american diets based on maize, beans and squash and the associated niacin-releasing techniques of maize preparation forms a classic example. Similarly, rice, pulses and milk products provide a balance of amino acids for subsistence farmers in India. In situations where animal protein and fat provide the primary energy sources, such as among Arctic hunters and dryland pastoralists, adaptive practices including specialized preparation techniques and the use of wild plants ensure that essential vitamins and minerals are consumed.
While nutritional sciences have provided a framework for interpreting the adaptive significance of traditional systems, elucidation of the nutritional basis for health problems in contemporary contexts can guide the application of traditional knowledge and resources and of efforts in environmental conservation necessary for the identification of sustainable solutions.
ISSUES IN HUMAN HEALTH
Malnutrition is seldom seen in ecological terms, perhaps due to a lack of historical reference points (baseline data) or perspectives on antecedents associated with the development of nutritional problems. However, analysis of traditional systems often reveals underlying environmental factors. Overpopulation reflects a breakdown of traditional ecological balance; without opportunities to disperse geographically, expanding populations exceed the carrying capacity of their environment. Decreased mortality rates associated with modern health care contribute to this.
Overpopulation and factors that undermine the capacity to produce food lead to inadequate food intake and/or consumption of nutritionally poor foods. Famine may be associated with environmental extremes that in many cases have anthropogenic causes. Micronutrient malnutrition may reflect a disruption of traditional patterns of subsistence resulting in reduced access to and intake of crucial biological resources.
So-called diseases of affluence such as diabetes and coronary heart disease also represent disruptions of human-environmental relationships. Traditional subsistence patterns couple energy expenditure for food procurement and other activities with intake of foods with low energy density. In addition to energy over-consumption in diets of industrial societies, increased reliance on processed foods may affect health by reducing intake of nutrients and non-nutrients that protect health more subtly.7
Changes in disease factors
Nutritional status is compromised by disease factors of environmental origin and is a critical factor in the severity and prevalence of illnesses. Disruption of natural ecosystems can increase rates of infectious disease by increasing rates of exposure to vector-borne disease such as malaria, leishmaniasis, or dengue,8 or through impacts on density-related factors such as sanitation and direct person-to-person transmission. Major public health problems of global importance such as tuberculosis, gastrointestinal diseases, measles and respiratory disease all reflect the interaction of nutritional and environmental factors. 9 Malnutrition may result in micronutrient deficiencies such as vitamin A and iron that affect the immune system and compound these and other diseases.10
Cancers can be attributed to contaminants, and fear of
exposure can lead people to abandon components of their traditional food
DYNAMICS OF LOSS OF ENVIRONMENTAL HEALTH
Ecosystem destruction and loss of biodiversity
In areas of traditional subsistence, large-scale economic enterprises such as forestry, mining and agriculture activities destroy - or make conditions unsuitable for - the plants and animals on which people meet their nutritional needs. Deforestation, destruction of watersheds and changes in land use can dramatically affect water relations and meteorological cycles; these in turn contribute to crop failures and drought. In addition to directly affecting nutrient intake, loss of bio-resources affects economic livelihood. Migration and colonization such as that occurring in areas of tropical forests,12 while motivated by the need to relieve problems of overpopulation in other areas, lead to profound environmental change and health problems of the type described above for both immigrants and indigenous populations.
Increasing population and urbanization intensify the challenge of obtaining adequate nutrition in a sustainable manner. Urban populations make increasing impacts on the environment through market demands, by settling in agricultural areas, and through pollution associated with industrial growth and urban waste. In this situation the urban poor are doubly affected by deficiencies in diet and by the negative consequences of living in unhealthful conditions.
Urban diets in developing countries - often characterized by energy excess, reliance on fat frying and associated oxidizing conditions and low intake of fruits, vegetables and other components of traditional forms of ingestion7 - are setting the stage for an emerging epidemic of diabetes, cardiovascular disease and cancer facing the next generation.
Globalization of agriculture
Urbanization and international trade in food and income-generating crops stimulate commercial agriculture. While modern technology-based farming is essential for producing food for the growing population in local cities and globally, methods that depend heavily on energy inputs are rarely benign in terms of environmental impacts. Consumption of fossil fuels and petrochemicals in the form of fertilizers or pesticides has global climatic consequences, while locally intensive mechanized cultivation can lead to erosion and destruction of the soil and eventual loss of productivity. Run-off leads to the contamination of water systems and destruction of the productive capacity of marine and lacustrine resources. In many cases economic pressures may lead to development of land that is not well-suited for agriculture.
Pesticides have both local and global impacts on diet and nutrition. Apart from the toxicological consequences of direct exposure, local contamination may reduce the dietary options of local populations. Herbaceous plants that grow as weeds in fields or along margins and consumed as pot herbs and relishes are traditionally important supplements and sources of micronutrients for many people.13 Herbicides, fungicides and insecticides may eliminate these or make them unfit for consumption. The consequences of persistent organic pollutants (POPS) that are transported in the atmosphere are felt on traditional food systems far removed from major sites of pesticide use11, (see box for information on the POPs treaty, p. 24).
Erosion of food crop diversity
In many regions of the world, multiple pressures are threatening plant diversity. Global modern agriculture typically focuses on yields of a few crops. Years of genetic engineering have brought about high yielding, pest- and drought-resistant varieties of a small number of distinct food crops. Whereas over seven thousand plant species have been traditionally used for food, three species - rice, wheat and maize - account for sixty percent of the total energy intake in the human diet.14 The sheer magnitude of agricultural effort applied to these three crops has led to a decline in the consumption of more diverse grains. There has been an accompanying decrease in the variety of vegetable and fruit species consumed. Influences compounding this trend include cultural change and urbanization.15 Additionally, many traditional foods are now associated with being poor or backward. This has lead to changes in dietary patterns and the amount of dietary diversity. Little is known about the impact of these dietary changes on human nutrition.
The sheer magnitude of agricultural effort applied to
rice, wheat and maize has led to a decline in the consumption of more diverse
Genetic modification holds considerable promise for selective improvement of plant nutrient composition. Although genetically modified organisms (GMOs) are currently subject to considerable scrutiny for their potential adverse affects on human health, the ecological impacts of this technology are probably greater and also require careful evaluation. One of the current trends in the use of GMOs in agriculture is their reliance on monoculture and the reduction of plant diversity within fields and field margins. The requirements of GMOs as they are currently being developed for agriculture do not allow for the diversity of weeds and other plants that are typically important nutrient sources from fields of staple crops.13
Although the precept that potential benefits derived from modern agriculture and associated technological solutions to food and nutritional problems must be balanced against environmental costs is recognized in principle, the necessity for sustainable forms of commercial agriculture in developing countries is, generally speaking, given less weight than in industrial countries. In both contexts research and development of alternative technologies that demand less inputs, and are usually on a small scale, have much to offer in nutritional, environmental and social terms.
Consequences for rural populations
Populations living a subsistence lifestyle in rural environments range from those utilizing local resources in a traditional manner to landless peasants and agricultural labourers. The former group are most directly affected by reductions in biodiversity of plants and animals used for subsistence and as components of the environments in which these organisms live. Here environmental disruption can be the trigger for impoverishment and social disintegration. Loss of a traditional subsistence base can bring about the conversion of indigenous communities to landless labourers. Reduced economic and subsistence options lead to malnutrition. Continued environmental deterioration further reduces the means people have of meeting their needs.
Knowledge of traditional resources and subsistence methods forms an important aspect of indigenous culture that is fundamental to identity of culturally defined groups. Continuance of cultural practices is important in contributing meaning and self-affirmation in the lives of individuals. Because resource exploitation is often a social activity, disruption of subsistence patterns weakens social bonds. Social disintegration leading to the loss of traditional means of subsistence can lead directly to malnutrition. Disturbance in social organization and lack of social cohesion can be synonymous with impoverishment that in turn affects nutritional status.
The issue of whether traditional systems are inherently more sustainable than modern alternatives can be approached in ecological and sociocultural terms. The dynamic interaction between the biological imperative of growth characteristic of human societies, biophysical constraints, and cultural controls appears to be more at equilibrium in traditional societies. Strong bonds with land and spiritual values associated with the natural world, characteristic of indigenous cultures, have been suggested as contributing to an inherent conservation ethic.
Loss of a traditional subsistence base can bring about
the conversion of indigenous communities to landless labourers - Reduced
economic and subsistence options lead to malnutrition
NUTRITION FOR SUSTAINABLE ENVIRONMENTS
Nutrition research as it identifies fundamental human needs provides essential information on the consequences of environmental degradation and change on human well-being. In turn nutritional status of populations, as a recognisable outcome, should guide other scientific disciplines and programs of ntervention in thei identification of sustainable solutions to the environmental and economic problems facing global communities.
Concerns for quality in crop improvement efforts seldom include nutrition, or, if they do, tend to focus on protein. Some research and intervention programs have focussed on micronutrient priorities such as vitamin A or minerals through genetic improvement, crop diversification and considerations of soil properties. More attention needs to be applied to identific ation of crop varieties and minor crops with selective nutritional assets and to the nutrient and phytochem ical analysis of indigenous crops and wild edible species. In particular greater importance should be given to the genetic diversity of plant species and the high micronutrient content present in a variety of different fruits and vegetables.
While such institutional approaches are essential to address problems of a global magnitude, national efforts, most importantly of local communities, are also important. Locally-focussed multi-disciplinary activities that combine nutrition research, ethnobotany and ecosystem and resource management with health care initiatives, and which embrace participatory models of empowerment and initiative, offer real hope for addressing problems at the levels where people are directly affected.
Major health problems of the 21st century relate to nutritional deficiency and to dietary change in both rural and urban settings. Combined with understanding of traditional systems and resources, nutritional analyses help to identify the biological and sociocultural components of solutions. Addressing nutritional needs offers a primary rational for the preservation of traditional systems of knowledge and life-style, the conservation of wild and cultivated resources, and the sustainable use of the environments in which they are located.
1. Pellett PL (1993) The World Declaration on Nutrition from the International Conference on Nutrition. Ecology of Food and Nutrition 30:1-7.
2. FAO/WHO (1994) International Conference on Nutrition: Plan of Action for Nutrition. Ecology of Food and Nutrition 32:5-31.
3. Convention on Biodiversity. 1992. http://www.biodiv.org/chm/conv/default.htm
4. FAO (1999) CGRFA-8/99/3 http://www.fao.org/
5. Kuhnlein HV, Receveur O (1996) Dietary change and traditional food systems of indigenous peoples. Annual Review of Nutrition 16:417-42
6. Johns T (1996) Phytochemicals as evolutionary mediators of human nutritional physiology. International Journal of Pharmacognosy 34:327-334.
7. Johns T (1999) The chemical ecology of human ingestive behaviors. Annual Review of Anthropology 28:27-50.
8. Spielman A, James AA (1990) Transmission of vector-borne disease. In: Warren, KS and Mahmoud, AAF eds. Tropical and Geographical Medicine McGraw-Hill Information Services Company, New York.
9. Platt AE (1996) Infecting Ourselves: How Environmental and So cial Disruptions Trigger Disease Worldwatch Institute, Washington.
10. Tomkins A (2000) Malnutrition, morbidity and mortality in children and their mothers. Procedures of the Nutrition Society 59:135-46
11. Kuhnlein HV, Chan HM (2000) Environment and contaminants in traditional food systems of northern indigenous peoples. Annual Review of Nutrition (20), 595-626.
12. Hladik CM, Hladik A, Linares OF et al. (eds) (1993) Tropical Forests, People and Food. UNESCO, Paris.
13. Price LL (1997) Wild plant food in agricultural environments: a study of occurrence, management, and gathering rights in Northeast Thailand. Human Organization 56:209-221
14. Eyzaguirre PB, Padulosi S, Hodgkin T (1999) IPGRI's for neglected and underutilized species and the human dimension of agrobiodiversity. In: Padulosi S ed. Priority-setting for Underutilized and Neglected Plant Species of the Mediterranean Region. IPGRI, Rome.
15. Chweya JA, Eyzaguire PB (eds.) (1999) The Biodiversity of Traditional Leafy Vegetables. IPGRI, Rome.
Contact: Timothy Johns, Centre for Indigenous Peoples Nutrition and Environment (CINE), Macdonald Campus, McGill University, Ste. Anne de Bellevue, Quebec, H9X 3V9, Canada
EMail: Johns@macdonald.mcgill.ca and Pablo B. Eyzaguirre, International Plant Genetic Resources Institute (IPGRI), Genetic Resources Science and Technology Group, Via delle Sette Chiese 142, 00145
FACTORY FARMING AND THE ENVIRONMENT
INTENSIVE LIVESTOCK PRODUCTION
At the end of the 20th century, intensive farming of animals for food was increasingly promoted as the answer to the needs of the developing world for an abundant and varied diet. The scenario of rapidly increasing consumption of meat, milk and eggs and of the intensification of animal production systems has been presented as both inevitable and desirable. The US-based Council for Agricultural Science and Technology, an organisation of US farm and agricultural science associations, stated in 1999 that when compared to grassland or mixed farming, the intensive (industrial) systems of producing animal food have contributed most to the relatively low-cost meat and milk enjoyed by consumers in developing countries.1 Similarly, a paper from FAO research and policy experts published in 1998 reported that The trend of further intensification and specialisation of demand-driven production is inescapable.2
Salespeople and investors from the major agricultural countries, development agencies and national governments are all taking a part in driving farm animal intensification - and it is happening fast, especially in pig and poultry farming. Fifteen years ago nearly all poultry rearing in Thailand was bac kyard production, whereas today less than a quarter of Thailands poultry are supplied from villages3. An investigation of animal farming in Thailand, Brazil, India, China and South Africa conducted for Compassion in World Farming during 2000 has showed an alarming picture of burgeoning intensive livestock production.3 Compassion in World Farmings report argues that animal intensification is a misguided policy in the quest for better diets and that history proves the cost of intensive farming to the environment, to the animals, and to consumers and small farmers to be unacceptably high.
Battery cages for laying hens, here in use in Thailand, are being phased out in much of Europe
THE HISTORY OF FACTORY FARMING
Fifty years ago in Europe, intensification of animal production was seen as the road to national food security and a better diet. The policy was supported by guaranteed prices, encouraging high inputs of feed, fertiliser, pesticides and veterinary medicines. The intensive systems - called factory farms - were characterised by confinement of the animals at high stocking density, often in barren and unnatural conditions.
Productivity increased but the animals paid a high price in suffering. Caged in sow stalls or battery hen cages, farm animals are unable to exercise or to perform many natural behaviours. They suffer from diseases such as lameness, digestive problems and osteoporosis. Extreme selective breeding for high yield causes major health and welfare problems such as skeletal disease in fast-growing chic kens and mastitis in dairy cows. The environment has also paid a high price in terms of water, air and soil pollution, overuse of water and land and loss of biodiversity and landscape. As the British Government Panel on Sustainable Development recognised in 1997, Farming methods in the last half century have changed rapidly as a result of policies which have favoured food production at the expense of the conservation of biodiversity and the protection of the landscape.4
animal intensification is a misguided policy in the quest
for better diets
THE COST OF HIGH INPUTS
Intensive farming of high-yielding animals requires large amounts of protein-rich and energy-rich feed. This is necessary because the animals are confined and separated from natural sources of food and also because a forage diet is unable to satisfy the feed requirements of these highly selected animals. A high-yielding dairy cow may need 4700 kg of forage and 1600 kg of concentrate feed in a year.6 A feedlot beef animal needs 1400 kg of feed in the finishing period.7
Large amounts of the worlds cropland are given over
to producing food not for people but for confined animals... Animal feed
requirements put huge pressure on the worlds water
In turn, the need to grow animal feed helps drive the intensification of arable farming worldwide, leading to well-documented damage to water and soil resources and loss of biodiversity. Overuse of nitrate fertilizer reduces species diversity and damages soil fertility. A 10-year scientific study published in Nature has shown that long-term soil fertility is reduced and 60% more nitrate leaching occurs when crops are intensively farmed compared to methods using no agrochemical inputs.9 Nitrate pollution of surface and ground water - damaging biodiversity and drinking water - comes mainly from agriculture. A major use of pesticides is for animal feed production. Worldwide, the two crops which account for the highest percentage of herbicide sales are the feedcrops soya and maize.
Intensive animal farming is highly water-intensive. Over a third of the worlds cropland is now dependent on irrigation. Eighty seven percent of fresh water consumed is used for agriculture,10 while the UN predicts that 40 countries will suffer from extreme or absolute water shortages in the next 20 years.11 Animal feed requirements put huge pressure on the worlds water resources. It has been estimated that it takes 100 times more water to produce one kg of beef than to produce one kg of wheat.10 Irrigation itself causes salinization, estimated to affect about half of all irrigation systems worldwide.12 In addition, intensive agriculture is highly dependent on fossil fuel energy for pumping and for fertilizer production.
INADEQUATE POLLUTION CONTROL
By the end of the 20th century, it was generally accepted that intensive animal farming had caused environmental pollution wherever it had become established - and even in countries where regulatory frameworks are strongest.
Europe and the US have shown that pollution from ammonia, nitrate and phosphate arising from animal manure and slurry becomes a serious problem when animals are concentrated on unnaturally small areas of land in intensive farms. Slurry is a very polluting liquid mixture of urine and faeces, collected in intensive animal units. The US Department of Agriculture has stated, The continued intensification of animal production systems without regard for the adequacy of the available land base for recyling presents a serious policy problem.13 Large-scale air and water pollution incidents affect US factory farming areas, such as North Carolina (pigs) and Chesapeake bay (poultry). In the Netherlands, the problem of disposing of animal slurry has become so serious that pig production will have to be reduced by 25% to meet environmental standards. Agriculture contributes 80-90% of the ammonia pollution and 50-60% of the nitrate pollution in Europe.14 Intensive animal farming is an important source of emissions of carbon dioxide, methane, nitrous oxide and ammonia, variously associated with global warming, ozone depletion and acid deposition.
There is little or no pollution control currently in many developing countries. This means that, as in Europe and North America, liquid slurry from factory farms can pollute surrounding land and waterways, while peri-urban intensive units cause serious environmental nuisances.
ENVIRONMENTALLY-FRIENDLY ANIMAL FARMING
In the second half of the 20th century intensive animal farming in the industrial world, such as in Europe and North America, caused great suffering to animals and great cost to the environment. Many people would argue that a high global consumption of animal products will always be unsustainable - given the existing demands of feed production and waste disposal. Others argue that the solution is to take more of the old medicine. They believe that the expansion of animal production in developing countries can be met by increasing the worlds cereal output (arable intensification) and increasing the feed conversion of animals (intensification of animal husbandry). 15 We are now in a situation where the consumption of animal food and intensive animal farming are escalating in the developing world. But it is not too late for policy-makers to change direction.
1. Council for Agricultural Science and Technology (1999) Animal Agriculture and Global Food Supply Task Force Report No. 135, Executive Summary.
2. Fresco LO, Steinfeld H (1998) A Food Security Perspective to Livestock and the Environment. Livestock and the Environment, Proceedings of the International Conference on Livestock and the Environment, Ede/Wageningen, the Netherlands, 1997, ed. Nell A J. International Agricultural Centre, Wageningen.
3. Cox J, Varpama S (2000) The Livestock Revolution; Development or Destruction? Thailand Report. Compassion in World Farming, Petersfield, Hampshire, UK.
4. British Government Panel on Sustainable Development (1997) Third Report. Department of the Environment.
5. Pretty JN, Brett C, Gee D et al., (2000) An assessment of the total external costs of UK agriculture. Agricultural Systems 65: 113-136.
6. Berentsen PBM, Giesen GWJ (1996) Economic aspects of feeding dairy cows to contain environmental pollution. Progress in Dairy Science, ed. Phillips CJC, CAB International, Walling-ford.
7. Guyer PQ (1996) Grain processing for feedlot cattle. NebGuide G73-14-A, Institute of Agriculture and Natural Resources, University of Nebraska-Lincoln. Electronic version.
8. European Parliament (1999) Europes deficit in compound feeding stuffs and Agenda 2000. Agriculture, Forestry and Rural Development Series, working document AGRI-110.
9. Tilman D (1998) The greening of the green revolution. Nature 396:211-212.
10. Pimentel D, Houser J, Preiss E et al. (1997) Water resources: agriculture, the environment and society. BioScience 42:97-106.
11. Houlder V (1999) UN warns of water wars in the next century. Financial Times, 19th March 1999.
12. Umali DL (1993) Irrigation-induced salinity: a growing problem for development and the environment. Technical paper no. 215, World Bank, Washington DC.
13. US Senate Committee on Agriculture, Nutrition and Forestry (1997) Animal waste pollution in America: an emerging national problem. Report by Minority Staff for Senator Tom Harkin.
14. Carter A, Lord E, Webb J et al. (1999) Minimising agricultural pollution of soil, water and air. Agriculture and the Environment, Ministry of Agriculture, Fisheries and Food, London.
15. Delgado C, Rosegrant M, Steinfeld H et al. (1999) Livestock to 2020; the Next Food Revolution. Food, Agriculture and Environment Discussion paper 28. IFPRI, FAO and ILRI.
The report The Livestock Revolution; Development or Destruction?, by Janice Cox and Sari Varpama, published in September 2000, together with reports on specific countries, is available from Compassion in World Farming Trust, 5a Charles Street, Petersfield, Hampshire, GU32 3EH, UK
Contact: Jacky Turner, Senior Research Officer, Compassion in World Farming Trust, 5a Charles Street, Petersfield, Hampshire, GU32 3EH, UK EMail: email@example.com Web: www.ciwf.co.uk
ABBATOIR BLOOD USED IN FOODS: AN EXAMPLE OF NUTRITION-ENVIRONMENT INTERACTION
Andreas Mäurer and Klaus Schumann
From Biblical times, bovine, ovine, porcine and avian flesh has been prepared by bleeding through the carotid vessels. Blood conserved using hygienic, sterile procedures is a food source with a long-standing tradition in cuisines around the world, e.g. for the production of blood sausages. Due to increased meat consumption, however, exsanguination blood quantities far exceed the demand. A biodegradable waste-product, blood should not be released into general drainage sewage, but rather be disposed of in an appropriate manner which will not damage the environment. Blood collected and conserved in an unsanitary fashion can be used as feed for domestic carnivore pets. In the context of nutrition and environmental contamination, we focus here on a unique example of synergistic interaction. The maximal usage of slaughterhouse blood as a resource for human and domestic - animal feeding could include channelling this byproduct into the food fortification effort aimed at reducing iron deficiency and removing this waste product from the environment.
Prehistoric humans were hunters and thus, carnivorous, which may explain the development of specific mechanisms for intestinal heme-iron absorption. Enzymatic digestion of hemoglobin to heme and globin degradation products in the intestinal lumen seems to prevent the aggregation of heme molecules and increases absorption rates markedly over those found for highly purified heme products.1
Heme iron is highly bioavailable with absorption rates in the range of 20-32%.2,3 Absorption rates of 20% were maintained when the heme iron concentration in a meal ranged between 0.28 and 4.48 mg,4 showing that the percentage of heme iron absorbed decreases very little with increasing quantities in the diet.5 This is in contrast to inorganic iron and contributes to the low incidence of iron deficiency in populations with high meat consumption. Also, iron-binding ligands have little effect on heme iron which is largely inaccessible in its porphyrin shell. Thus, simultaneous intake of ascorbic acid does not increase and the chelator desferrioxamine does not decrease the absorption of heme iron.6,7 Accordingly, inhibition of heme-iron absorption by food ligands such as phytate and tannin is low.8 This is in contrast to non-heme iron, the absorption of which is severely impaired by food ligands9 which are common in black beans, corn, rice and other cereals.
The problem with the use of fresh blood products for food fortification is that they degrade rapidly, making transport and storage difficult. Processes to separate the heme from abattoir blood have been refined and applied since the 1980s. Examples from Chile,10,11,12,13 the United Kingdom14 and Spain15 document the potential of hemoglobin fortification. There are an estimated two billion iron-deficient individuals in the world, primarily in developing countries. This projection for the use of animal blood would, in effect, bring a highly bioavailable source of iron to bear on the problems of iron deficiency and iron deficiency anemia in vulnerable groups. Hemoglobin is a macromolecule with a weight of 65,458 Dalton, 94% of which is globin. This leaves only 6% for the iron containing heme moiety, making hemoglobin a very bulky iron carrier.
Therefore, a simple and cheap method to split heme from the globin moiety was developed that can be used for bovine, ovine, porcine and avian blood. Splitting heme from globin increases the shelf life of the product and decreases the quantity of fortificant needed to add a defined amount of iron to a given food matrix. The production process includes smooth acidic hydrolysis of the hemoglobin and separation of the iron-rich heme aggregates by centrifugation. The separation method was designed for low technology with limited investment in equipment required. The process can be performed in less industral-ized countries and is comparably cheap. Assuming that blood as a waste product enters the calculation for free, the production cost is approximately $1.50 kg heme-product. One kg of heme-product corresponds to approximately 500 aliquots of 30 mg Fe. This quantity should last for 500 weeks, if a supplementation dose of three RDAs/week is assumed, corresponding to approximately $ 0.16 per capita/year. This figure is likely to decrease, if the production process were sc aled up for high quantity output. However, it does not contain the cost for the food matrix, mixing, storage and distribution. The separated globin could be utilized as a technical protein to improve the economics of the process.
In Guatemalan children fed heme-fortified refried black beans, the ability of such a partly purified heme product to reverse anemia and to build iron stores was at least equivalent to that of ferrous sulfate, which is regarded as a gold standard for iron availability studies. Moreover, the heme product was far superior to FeSO4 with regards to taste.16 The black color of heme limits its use to dark food matrices such as black beans or chocolate - flavored food products.
Taste and shelf-life of the fortified product is a key issue in iron fortification. In this context, an additional advantage of heme over inorganic iron is its low interaction with the food matrix. The formation of formylfurane, which gives a poor taste, was determined in potato-flips fortified with the new partly purified heme product. After 14 weeks of storage at 40 °C (2.7 mg Fe/100 g) the formylfurane content was ten times lower than in FeSO4-fortified flips. Accordingly, hemoglobin fortification of biscuits increased the peroxide index by less than 20% and no differences in taste and appearance were found after storage at 40°C for 60 days.10 Also, hemoglobin-fortified weaning food did not change organoleptic attributes after eight months storage at room temperature.15 Fortification of olive oil with partly purified heme (200 mg Fe/100 mL) showed limited lipid peroxidation. At the same concentration, FeCl3 fortification produced significant amounts of hexanal under these conditions. Thus, the production of a ß-carotene and heme iron-fortified, high-energy snack food based on palm oil seems possible to simultaneously fight iron and vitamin A deficiency. Until now iron has not been added to a fat-based matrix because of the risk of lipid peroxidation. This incompatibility has been an obstacle for a combined fortification-based intervention program against vitamin A and iron deficiencies, the most commonly observed micronutrient deficiencies worldwide.
1. Conrad ME, Cortell S, Williams HL et al. (1966) Polymerization and intraluminal factors in the absorption of hemoglobin-iron. Journal of Laboratory and Clinical Medicine 1966; 68:659-68.
2. Björn-Rassmussen E, Hallberg L, Isaksson B et al. (1974) Food iron absorption in man. Journal of Clinical Investigation 53:247-55.
3. Martinez-Torres C, Layrisse M (1971) Iron absorption from veal muscle. American Journal of Clinical Nutrition 24: 531-40.
4. Herbert V.(1987) Recommended dietary intakes (RDI) of iron in humans. American Journal of Clinical Nutrition 45: 679-86.
5. Bezwoda WR, Bothwell TH, Charlton RW et al. (1983) The relative dietary importance of heme and non-heme iron. South African Medical Journal 64:552-56.
6. Callender ST, Mallett BJ, Smith MD (1957) Absorption of haemoglobin iron. British Journal of Haematolology 3: 186-92.
7. Wheby MS, Spyker DA (1981) Hemoglobin iron absorption kinetics in the iron-deficient dog. American Journal of Clinical Nutrition 34:1686-93.
8. Lynch SR, Dussenko SA, Morck TA et al. (1985) Soy protein products and heme iron absorption in humans. American Journal of Clinical Nutrition 41:13-20.
9. Hallberg L (1987) Wheat fiber, phytates and iron absorption. Scandinavian Journal of Gastroenterology 22 (Suppl. 129):73-79.
10. Asenjo JA, Amar M, Cartegena N et al. (1985) Use of bovine heme iron concentrate in the fortification of biscuits. Journal of Food Science 50:795-99.
11. Calvo E, Hertrampf E, Pablo S et al. (1989) Haemoglobin-fortified cereal: An alternative weaning food with high iron bioavailability. European Journal of Clinical Nutrition 43:237-43.
12. Hertrampf E, Olivares M, Pizarro F et al. (1990) Haemoblobin fortified cereal: A source of available Fe in breast fed infants. European Journal of Clinical Nutrition 44:793-98.
13. Walter T, Hertrampf E, Pizarro R et al. (1993) Effect of bovine-hemoglobin-fortified cockies on iron status of school children. A nationwide program in Chile. American Journal of Clinical Nutrition 57:190-194.
14. Martinez C, Fox T, Eagles J et al. (1998) Evaluation of iron bioavailability in infant weaning foods fortified with haem concentrate. Journal of Paediatric Gastroenterology and Nutrition 27:419-29.
15. Martínez-Graciá C, Lopez Martinez G, Berruezo GR et al. (2000) Use of heme iron concentrate in the fortification of weaning foods. Journal of Agriculture and Food Chemistry 48:2930-36.
16. Romero-Abal ME, Solomons NW, Bulux J et al. (2000) Anemia response to a heme-iron fortificant in black beans. FASEB Journal 14: A753 (Abstr.).
Contact: Klaus Schûmann, Email: K.Schuemann@lrz.uni.muenchen.de
ALUMINUM AND HEALTH
Recommendations arising from an interdisciplinary working group on Aluminum Neurotoxicology, sponsored by the European Union and presented at the recent First International Conference on Metals and the Brain
Padova, Italy, September 20-23, 2000
All populations are exposed to aluminum, an environmentally abundant element. The neurotoxicity of this metal has been known for more than a century. More recently, it has been implicated as a causal factor in some pathologies related to dialysis treatment, including encephalopathy, bone disease and anemia. In addition, it has been suggested that aluminum exposure is a cofactor in the development of some neurodegenerative diseases, including Alzheimer's disease, although direct evidence for this is still controversial. Examples of aluminum neurotoxicity are well recognized in experimental animals and in individuals with renal failure (due to aging, intoxication or renal disease), and there are grounds to link neurodegenerative disorders to aluminum exposure. Furthermore, an increased concentration of aluminum in infant formulas and in solutions for home parenteral nutrition has been associated with neurological consequences and metabolic bone disease.
For all these reasons, the EU-sponsored Working Group on
Aluminum Neurotoxicology proposes the following recommendations as guidelines to
avoid risks due to aluminum accumulation and potential toxicity. These
recommendations will be updated when relevant new scientific data become
1. It would be valuable to define as completely as possible which groups are at risk for iatrogenic aluminum loading, and under which conditions aluminum exposure represents a health hazard. The more complete our knowledge the better basis we will have to judge whether different types of aluminum exposure are hazardous to the general population or to susceptible subgroups.
2. A provisional list of groups at risk of iatrogenic aluminum loading should include, at a mininum, people with impaired renal function, infants, the elderly and patients on total home parenteral nutrition. Where such exposure occurs, serum aluminum concentrations should be less than 30 µg/L and possibly lower.
3. Urinary aluminum is an indicator of aluminum absorption: the ratio of excreted aluminum to retained aluminum depends on the integrity of renal function.
4. Aluminum may enter the human body by mouth, intravenous infusions and through the environment. Specific controls are needed to reduce each risk of exposure.
5. Aluminum in drinking water should be less than 50 µg/L. Silicon is relevant to aluminum toxicity and, therefore, water silicon concentrations should be monitored in parallel.
6. Aluminum content should be declared in all food preparations and pharmacological products.
7. Citrate-containing compounds appear to increase the bioavailability of ingested aluminum. Therefore, particular care should be taken to avoid these compounds in combination with aluminum - containing drugs. With citric acid, the enhanced gastrointestinal absorption may be compensated for by a parallel increase in urinary aluminum excretion, where there is good renal function. However, it is strongly suspected that other dietary acids (for example succinic and tartaric acids) also increase aluminum - bioavailability but do not cause any compensatory increase in urinary excretion. Ascorbate and lactate also significantly enhance gastrointestinal absorption of aluminum.
8. It is recommended that acidic food, for example acid cabbage and tomato, should not be cooked or stored in aluminum ware. It has been shown that the juice of acidic cabbage cooked in aluminum pots can contain aluminum levels of up to 20 mg/L.
9. Special efforts should be taken to prevent contamination of foods and beverages with aluminum either directly or during preparation, in particular with regard to infants, the elderly and individuals with suboptimal renal function.
10. Magnesium depletion increases the risk of aluminum accumulation especially during pregnancy and in the neonate with possible consequences for normal growth and development. Magnesium depletion is also common with aging.
11. Iron depletion also increases the risk of aluminum accumulation, because iron and aluminum share common carriers.
12. Aluminum in all intravenous fluids should be controlled, monitored and labeled. There is a general consensus that the aluminum content of intravenous fluids used for children and adults with renal failure or undergoing dialysis, should be as low as possible and in any case no higher than 10 µg/L.
13. Parenteral nutrition fluids that are high in aluminum should not be used.
14. There is a need for more research on the absorption, metabolism and neurotoxic effects of aluminum in occupational settings. It would be useful to monitor the total aluminum content in serum and urine of exposed workers. Furthermore, there should be detailed neuropathological studies at autopsy of workers highly exposed to aluminum, and comparison with similar studies in long-term dialysis patients in the general population.
INFANTS AND CHILDREN
15. Preterm infants are particularly vulnerable to aluminum because of their immature renal function. Particular attention should be directed to artificial milks, especially soy based infant formulas or feeds, which may contain high concentrations of aluminum.
16. Prospective studies on the possible effects (including cognitive, behavioral, motor, delayed calcification for example) of elevated aluminum exposure in healthy children as well as in children with different degrees of renal failure and other pediatric groups.
Contact: Professor Paolo Zatta, Dept of Biology, University of Padova, Padova, Italy; EMail firstname.lastname@example.org