|SCN News, Number 09 - Focus on Micronutritients (ACC/SCN, 1993, 70 p.)|
The following article is adapted and edited from the paper Best Practices in Addressing Micronutrient Malnutrition by Judith McGuire, The World Bank, 1818 H Street NW, Washington DC, 20433.
Vitamins and minerals cannot be synthesized by the human body. They must be provided by the diet. The amounts needed are small - micrograms or milligrams a day - so they are called micro nutrients. They are necessary for the regulatory systems in the body, for efficient energy metabolism and for other functions (cognition, immune system, reproduction). In this paper the focus is on vitamin A, iron and iodine even though there are many more micronutrients including some that are suspected of being deficient in some developing countries. The three focal nutrients were selected because they are known to be deficient widely in developing countries, we know how to treat them, and we can measure progress unambiguously. Deficiencies of these nutrients cause illness, death, learning disabilities, and impaired work capacity.
The causes of deficiency vary from nutrient to nutrient and across regions. Iodine deficiency is largely an environmental problem - iodine-deficient soils and water exist in the high mountain ranges and in flood plains where the primordial iodine has been depleted over millennia. Plants grown in such soils and water lack iodine, so human beings and animals eating those plants become iodine deficient (iodine is not a necessary nutrient for most plants). It is not unusual to see goitres in cows and sheep just as in human beings. The animals exhibit low wool production, inadequate growth, and poor reproductive performance. Human beings are affected even more profoundly. Certain foods - cassava and cabbage, for instance - impair the utilization of iodine in the body and can precipitate iodine deficiency in marginally adequate populations. Good food sources of iodine (seaweed and seafood) are highly perishable, culture specific, often expensive and are rarely eaten by affected populations. Food fortification is usually necessary for prevention of iodine deficiency in iodine-depleted geographic areas. Iodized salt is the commonest micronutrient-fortified food.
Iron deficiency is largely due to the low absorption of iron from foods. Red meat and animal blood (consumed in many traditional societies) are the best sources of highly absorbable iron, but meat is not affordable or religiously acceptable to large numbers of people in developing countries. For infants, most iron comes from breastmilk in which the iron is highly absorbable but present in low concentrations. Most of the iron in the diet comes from grains, legumes, and vegetables, from which the absorption is usually 5% or less. Absorption can be increased three to seven-fold by eating acidic foods, especially those rich in vitamin C, along with iron-containing foods. Tea and coffee can severely inhibit iron absorption when taken at the same meal. The low absorption of iron in the diet can double the requirement for iron intake.
Vitamin A is found preformed in animal foods (especially liver and milk). Vitamin A precursors, found primarily in plant products (generally leafy green vegetables, yellow and red fruits and vegetables, and red palm oil), can be converted into vitamin A in a ratio estimated as 6:1. Vitamin A intake is often inadequate because of the seasonality of food sources, the early abandonment of breastfeeding, and the practice of not giving vitamin A-rich foods to young children. Vitamin A is also destroyed by improper processing and storage because it decomposes in light. Vitamin A absorption may also be impaired where the diet is very low in fat or where intestinal parasites are prevalent.
During rapid growth, micronutrient intake must increase or else growth failure or deficiency diseases develop. It is during these periods that deficiency symptoms are most prevalent. For this reason, preschool-aged children, adolescents, and reproductive-aged women are high priority target groups. School-aged children are a secondary target group because of learning problems associated with micronutrient deficiencies. Anaemic adult workers are a third target group; for example, iron supplementation has been shown to significantly improve work output in Indonesia and Kenya.
There are important interactions between micronutrient deficiencies and infectious diseases. Vitamin A deficiency and measles, for instance, act synergistically to exacerbate the severity of measles and precipitate vitamin A blindness and death. Severe anaemia is often jointly caused by malnutrition, malaria, and hookworm. It is difficult to attribute a proportion of micronutrient deficiencies to these health problems, but surely prevention of micronutrient deficiencies must play a role in infectious disease control, and vice versa.
Iron deficiency and iodine deficiency are associated with abnormal lethargy and low work potential. Work output of men working on piece rate jobs has been directly related to the severity of anaemia. For a 10% increase in haemoglobin, there is a 10-20% increase in work output.
Night-blindness, a reversible symptom of vitamin A deficiency, impairs the ability to see under poor lighting conditions. Women often show increased prevalence of night-blindness during pregnancy which may mean their ability to make meals, mend clothes and take care of other chores in the semi-darkness of the home is compromised. Children may be unable to get around in the dark and students may be incapable of studying except in broad daylight. Soldiers may be unfit for duty except in broad daylight.
When moderate or severe deficiencies coincide with critical development stages, they can cause prolonged or permanent dysfunction. Iron deficiency, for instance, is associated with poor attention span, inadequate fine motor skills, and reduced memory retention. If this occurs during critical stages in preschool cognitive development or during schooling when specific skills are being taught then the child may never catch up. In Chile, investigators have found that iron deficiency in early infancy, even if corrected upon diagnosis, still resulted in learning disabilities years later in school. Investigators in Thailand and Indonesia found that iron-deficient children treated with iron supplements improved (cognitive skills and performance on achievement tests) but they never performed at the level of non-anaemic children.
Iron-deficiency has been associated with prematurity and low birth weight (LBW). While adequate health and nutrition care can compensate for prematurity or LBW, often such children have lingering frailties (immune system dysfunction, growth failure) which increase the child's risk of morbidity and mortality throughout childhood.
Deficiency can be Lethal
All three micronutrient deficiencies are associated with increased mortality. Severe vitamin A deficiency (keratomalacia) has very high fatality rates (60%) but even subclinical deficiency is associated with a 23% increase in preschooler mortality in areas with endemic vitamin A deficiency. Severe anaemia causes heart failure. It is estimated that 20% of maternal mortality is due to anaemia, directly (heart failure) or indirectly (inability to tolerate haemorrhage). In addition, fatality rates in children hospitalized with severe anaemia have been estimated to be 31 % unless they receive immediate blood transfusions.
Maternal iodine deficiency is responsible for high rates of still birth and neonatal mortality - on the order of 0.5 to 1% of pregnancies in endemic areas. In addition, foetal iodine deficiency can result in severe, irreversible mental retardation and neurological disorders (cretinism) and limited lifespan. Less severe handicaps associated with foetal iodine deficiency include deafness, muteness and mild to moderate mental retardation. These handicaps are irreversible and severely limit the learning capacity, occupational choices, and future earnings of these individuals.
Iodine-deficiency the woman on the left is adult
Vitamin A deficiency is not only potentially lethal, it also causes monocular or complete blindness. In endemic areas, blindness rates are about 0.01% of children under 6. The chances for a blind or visually handicapped child to get appropriate schooling are extremely rare in developing countries. These children also have limited options for earning a livelihood and become a long-term burden for their families.
Poverty & Deficiency
While poor people are more likely to suffer from micronutrient malnutrition, micronutrient intake is not necessarily linearly related to income. Iodine intake, for instance, may be constant regardless of income because its concentration in food is a product of environmental iodine concentration. The very wealthiest consumers may ingest adequate iodine because they can afford to buy seafood or iodized salt marketed in elite grocery stores, but most consumers get insufficient iodine.
In the case of iron, income does seem to be related to both quantity and quality of iron content of the diet. Iron is found in most staple grains and legumes. As income rises initially, so does intake of staple foods. As income rises further, meat consumption increases and hence the quality (absorption) of iron in the diet increases.
Vitamin A and Vitamin C (which helps in iron absorption) behave erratically with respect to income. Because these vitamins are concentrated in perishable fruits and vegetables (especially dark, green, leafy vegetables), consumption depends very much on availability. In rural areas, wild foods contribute considerably to vitamin A intake. These wild foods may have an image of low status foods or foods for unsophisticated consumers and it is not unusual to see vitamin A consumption decrease as income rises in the bottom quintile as traditional foods are disdained. In the highest income groups, as cultivated fruits, refrigeration, and dairy products become more affordable, vitamin A intake rises further.
Higher micronutrient intakes do not necessarily follow increases in income or calories because consumers in general neither know what nutrients they need nor what food provides those nutrients. The micronutrient content of foods is a hidden quality to the uninformed consumer. Calories or bulk are more detectable since everyone knows when he is hungry and when he has had enough to eat. People generally eat to fill their stomachs and perhaps to meet emotional needs (if they have that luxury). There is no natural hunger for iron, vitamin A or iodine. The signs that someone hasn't eaten enough of them are subtle and delayed and they may not seem severe or diet-related to the person directly affected. Even cretinism and blindness are more likely to be attributed to divine retribution than they are to diet. This lack of consumer awareness of micronutrient intake and deficiency makes consumer education central to the success and sustainability of any micronutrient programme. Appropriate monitoring and surveillance are needed to create awareness of effects of micronutrient programmes on well-being.
Some micronutrients (particularly vitamins A and C and iodine) are heavily concentrated in a few foods, so just eating more food or more kinds of food is not necessarily going to give more of those micronutrients unless consumer demand has been directed to the right foods. Even apparently similar foods differ dramatically in their micronutrient content. In the Philippines, for instance, horse radish tree leaves contain 14mg of vitamin A per 100 grams while sweet potato leaves, which for all intents and purposes serve the same culinary role, contain only 3mg per 100 grams. If the price of horse radish tree leaves increases, people may substitute more sweet potato leaves but probably not in a ratio of one-to-four.
Over the last twenty to thirty years, per capita income has risen in most regions, and calorie availability has, in general, paralleled per capita income trends. Micronutrient trends, however, bear little resemblance to calorie trends.
Food and agriculture policies can affect the consumption of micronutrient-rich foods by altering their availability and price. Agricultural policies can promote horticultural crops, legumes, edible tree crops, social forestry and, cropping patterns and preservation practices that nurture and conserve micronutrient-rich foods. Agricultural research can enhance the concentration and productivity of micronutrients in crops. General agriculture sector efforts can be used to enhance production of fruits and vegetables, red meat for local consumption, legumes, and tree crops bearing edible leaves. Particular attention needs to be paid to the problems of marketing perishable foods.
Improving the efficiency and coverage of health care systems should have a positive effect on micronutrient malnutrition, through improved health and hygiene, early intervention in disease, and monitoring growth and development. In a good health system, personnel are trained to detect and treat deficiencies, efficient management and logistics of pharmaceuticals assures ready supply of supplements, and, most importantly, the most vulnerable economic groups have access to health care. In order to treat severe deficiency states, health care providers need to know how to diagnose the deficiencies, have on hand the appropriate pharmaceutical supplies, equipment, and counselling materials, and a referral system is needed for intractable or severe cases. Preventive micronutrient programmes are needed where micronutrient malnutrition is a public health problem, even where health systems work well.
In addition to the distribution of supplements, health providers need to prevent or treat the diseases that exacerbate micronutrient malnutrition - measles and acute respiratory infections, for instance, can precipitate vitamin A deficiency. In vitamin A deficient regions, all cases of measles, chronic diarrhoea, acute respiratory infections and severe malnutrition should be treated with vitamin A according to therapeutic protocols. Hookworm increases iron losses. Malaria causes anaemia through mass destruction of red blood cells and is especially serious for pregnant women. Excess fertility also drains women's iron stores since each pregnancy exacts an iron (and probably other micronutrient) cost to the mother unless remedial supplementation takes place. Prolonged breast feeding can extend the interbirth interval and thereby enable the lactating women to rebuild iron stores. Attention to these underlying health problems is a necessary adjunct to direct micronutrient programmes but it cannot address the primary causes of micronutrient malnutrition.
The solutions thus go well beyond traditional health and nutrition systems. In order to generate multisectoral strategies and maintain momentum, it is often politically expedient to identify micronutrients as a special topic in human development which means that no single sector or institution owns micronutrients. While certain health structures may deliver micronutrient supplements for the short term (for example. Expanded Programme on Immunization delivery of iodine or vitamin A capsules), private food industry (with proper governmental oversight) may be responsible for delivery of the long term solution (e.g., iodized salt). National strategies must be opportunistic and use existing delivery vehicles where they serve the need. But effective strategies may need to create temporary vertical programmes to have measurable impact in the short term which, in turn, generates popular and political support for long term solutions. In sum, national strategy development must be multisectoral even though implementation is sectoral. It must take a very specific look at micronutrients separately from other health and nutrition problems even if the actual solution is ultimately done within the health sector or within on-going nutrition programmes.
One of the most attractive attributes of micronutrient interventions is their low cost and high cost-effectiveness. Costs are so low, in fact, that most of the intended beneficiaries can afford to pay for the food and pharmaceutical sources of micronutrients they need. The cost to society of micronutrient malnutrition far outweighs the cost of addressing it, so even though they may be inexpensive, it is defensible for the government to pay for such programmes for public health reasons.
Micronutrients are so inexpensive that all food secure households should be able to afford the nutrients, whether they derive from natural food sources or synthetic vitamins and minerals. Food-insecure households that periodically or continually do not get enough to eat in quantitative or caloric terms, are unlikely to be able to increase their intake of micronutrient-rich foods in the absence of an increase in overall food intake. They would probably need a targeted food distribution or subsidy programme. Although synthetic micronutrients are inexpensive, the markup on them by commercial manufacturers can be substantial. If private markets are to be used for production and distribution of micronutrients for public health purposes (as in contraceptive social marketing) then some regulation, consumer education, and price controls may be needed.
Assuring Access to Micronutrients
The options for addressing micronutrient deficiencies directly include:
1. Dietary change: Encouraging the consumption of nutrient-rich foods - red palm oil, dark green leaves, mangoes and various wild fruits - which may be available but underutilised by the deficient population.
2. Fortification of food or water: Adding nutrients to foods including bread, flour, noodles, water, salt, sugar, cookies, dairy products, weaning foods, curry powder, soya sauce, monosodium glutamate and bouillon cubes.
3. Pharmaceutical supplementation: Tablets, capsules, injections and oral tonics. In the case of vitamin A and iodine, megadose preparations provide protection for prolonged periods (4-6 months for vitamin A and 1-3 years for iodine).
To address micronutrient malnutrition is technically easy and cost-effective. What is required is political commitment and strategic planning. Very few countries with micronutrient malnutrition have mounted comprehensive national programmes to address the problem. This is largely due to lack of national advocacy and weak national institutions aggravated by insufficient donor interest. Iron programmes are the most neglected interventions, probably because supplementation through antenatal care has been the primary focus.
In order to increase the intake of micronutrients, the supply must be available, be it from pharmaceuticals, fortified foods, or natural foods. With pharmaceuticals, the key supply issues are physical access, logistics, and medical gatekeeping (via prescriptions). In the case of fortification, supply is assured first by making sure that the food vehicles for fortification, the level of fortification, and the chemical fortificants are properly selected and second, by making sure that the food industry is actually complying with fortification regulations. Where dietary change is promoted as the solution to micronutrient malnutrition, the availability and price of the foods promoted needs to be reinforced by food policies and agricultural programmes to promote production, processing, and efficient marketing of such foods. Often the key food is breastmilk, so health care professionals and maternity hospital administrators need to promote and protect breastfeeding.
Achieving and sustaining high coverage has been the most frequent problem encountered in micronutrient supplementation programmes. This is largely because such programmes have relied on existing health care delivery systems (which have low coverage) or because vertical delivery programmes were not able to sustain momentum. Flagging enthusiasm can be corrected by supportive supervision, retraining workers and marketing efforts to sustain demand for supplementation. Attributable impacts which are valued by beneficiaries should be monitored and reported back to decision-makers and service providers. In the absence of such positive feedback vertical programmes inevitably lose the enthusiasm and political support they originally garnered.
Most universal vitamin A supplementation programmes have failed to sustain high coverage over time. In Nepal, where a carefully designed pilot programme was carried out with highly motivated, trained and supervised community health workers, a vertical vitamin A supplementation programme achieved 75% coverage in the first year and increased to 80% in the second year. The integrated health care cum capsule alternative programme reached 72% of the target population in the first year and 81% in the second year. These rates are attributed to extensive training, close supervision, and high motivational level of community health workers. In Indonesia, a vertical programme was introduced in 1980 over and above the existing primary health care programme, to boost coverage levels rapidly. This came about because of strong political support for the Vitamin A programme. After two years coverage had increased from 6% to 77%. Today coverage has fallen below 50%. If a high intensity programme like Indonesia's achieves 65% coverage only with special attention, then normal programmes are not likely to achieve that coverage level at all. Moreover, the 20% left out are probably at highest risk for micronutrient deficiencies.
Vitamin A Saves Sight [Source: WHO. 'Let There Be Sight']
In Bangladesh the universal vitamin A supplementation programme, which uses existing health care providers, covers only about 36% of the target population (and probably the least vulnerable) largely because the public health care system has poor coverage. Furthermore, coverage has fallen over time because the intended beneficiaries do not perceive the need for vitamin A or the threat of vitamin A blindness. Very rarely is any social marketing done for capsule distribution programmes. Perhaps if the intended beneficiaries actively sought out the supplements, coverage would not be so low or decline over time. Social marketing of capsules in Indonesia increased capsule coverage from 27 to 40%.
One option in vitamin A supplementation programmes is medical targeting - delivering the supplements only to ill children (particularly those with xerophthalmia, measles, diarrhoea, and lower respiratory infections) on the rationale that those are the children who need the supplement most. Ill children are likely to be brought to a health center, which facilitates distribution. It is difficult to know the coverage of such programmes because the total target population (sick children) is unknown. It is also very difficult to undertake outreach in this situation. Nonetheless, medical targeting can be an economical means of getting vitamin A to a subpopulation of children who need it badly.
The Expanded Programme on Immunization (EPI) can deliver supplements to the periphery. In many countries, 80% or more of the young children are immunized. If the EPI structure can deliver supplements to those and older children in the same villages, a major advance in coverage of micronutrient supplements is possible. Even more important than reaching the 6-, 10-, and 14-week old children on immunization days, however, is case finding. Vaccinators need to seek out children and women in the same villages who missed vaccinations (or supplements). Because health personnel may not regularly see most patients, it is imperative to use every encounter with the formal health system, as an opportunity to reach target groups. This happens when a child is seriously ill or when the EPI vaccinator visits the village or home.
India seeks to improve young child coverage of vitamin A through a two-track approach involving both the health system and the Integrated Child Development Services (ICDS) programme. Under the Child Survival and Safe Motherhood initiative, children under one year of age receive vitamin A supplementation from health teams through the national immunization programme. Older preschool children receive vitamin A supplementation twice yearly from health workers operating at the ratio of one for around three villages. ICDS provides nutrition, health and education services to children under 6 years of age in close to half of India's rural areas. In villages where it operates, some 250,000 village-based workers administer vitamin A to children twice yearly. Where supplies are stable, vitamin A supplementation is available on demand; however, in most cases, administration is through semiannual campaigns. Midwives and, increasingly, ICDS workers, also are being enlisted to provide megadoses of vitamin A to women immediately after childbirth, thereby assuring maternal adequacy and transfer of sufficient vitamin A to babies through breast milk.
Other potential sources of increased coverage could be schools, agricultural extension agents, religious leaders and private pharmacies. In a Moslem country, for instance, iodine capsules could be distributed by local mosques on Eid, the celebration ending Ramadan. By using existing infrastructure and reaching out to vulnerable individuals in surrounding areas, coverage could be greatly expanded. The problem with a multisectoral delivery system is that at the state or national level it is difficult to coordinate among ministries.
Many countries have difficulty managing the supplies of pharmaceuticals (supplements), particularly at the clinic level. The logistics, supply management, procurement and management information systems issues which need to be addressed for pharmaceuticals in general, also need to be applied to micronutrient supplements. The World Health Organization's Essential Drugs Programme, which includes micronutrient supplements, has helped minimize the number of drugs that need to be ordered; and UNIPAK (UNICEF) has played an essential role in bulk procurement, quality control, and customized packaging for recipients. At the national level, however, resupply is often weak, procurement faulty, and distribution slow. A recent review of iron supplementation programmes by the ACC/SCN found that supply and logistics, not client non-compliance (as had been expected), were the primary causes for programme failure. In Tanzania, vitamin A was almost dropped from the essential drug lists because it was not moving. Health care workers did not know when to prescribe it. Further training of health care providers and community education remedied the problem. Demand generation should help signal to health care providers and managers that increased supplies are expected but the health care providers may also need training and motivation to meet increased demand from consumers and to prescribe correctly. Supply problems also appear when targeting criteria are not strictly adhered to. If low priority clients receive the supplements, then more needy individuals will be short-changed if supplies are limited.
Private stores should be considered as a potential delivery vehicle for micronutrient supplements where public drug management is not adequate. This has been tried with some success in contraceptive social marketing. In many places, private demand for vitamins is great, even if sometimes misguided. If private channels are used, great care must be taken to inform consumers about the kind of supplement to take, the dosage, who is to take it and when, and the dangers of overdosing. Regulation and monitoring of drug supply chains is needed to prevent fraud and assure quality control. In Nigeria, the private pharmacies are used to deliver the iron tablets prescribed at the health clinic. Supplementation programmes can be enhanced through education, targeting, and ensuring supplies are available.
Fortification of food has been responsible for eradicating most of the vitamin and mineral deficiencies in developed countries. Fortification of margarine with vitamin D is thought to have eliminated rickets from Britain and Northern Europe in the early part of this century. Fortification of refined flour with iron in the US and Sweden is credited with the dramatic reduction of anaemia. In Switzerland, which was the first nation to iodize salt in 1929, iodization immediately prevented cretins from being born where it was implemented. In Mali, new strategies have been tried by iodizing well water with substantial effects on iodine deficiency within a year. In Thailand, local water supplies have been fortified by hand mixing water with iodine. Commercial food fortification is particularly appealing because if the right food is selected, coverage takes care of itself. An ideal food vehicle for fortification is not available in every situation, however. But dietary habits are changing rapidly as food industries develop so fortification is likely to be feasible in the near future in most countries.
Once governments have mandated fortification, it is incumbent on food industry and its regulators to assure that the nutrients are in fact in the fortified food. In the past, fortification advocates have sought a single food for fortification but now it appears that it may be more effective to select several food vehicles in order to reach different segments of the population who have different diets. The cost of the fortified food should not be so high that it becomes unaffordable by the poor (who need it most).
Fortification is simple in food technology terms and defensible in public health terms even though it changes or limits consumer choice. For a number of public health reasons - prevalence among a broad spectrum of the population, serious and costly health effects of the deficiency, cost-effectiveness of prevention versus case management - it is justifiable to regulate industry in this instance because markets simply do not work efficiently for the socially optimum outcome. Consumers do not know or cannot detect beneficial or harmful substances in their food supply. They usually are not sufficiently informed to demand properly fortified food. Hence, governments need to intervene and one way is through regulating fortification. The two most important determinants of success in fortification programmes are selection of the right food(s) to fortify and industry compliance with fortification regulations.
While micronutrient deficiencies are a health problem, implementation of fortification is carried out by private food industry. Health Ministers in several countries are notable for being willing to exercise control over and motivate private industry. In fact, linkages between the Health and Industry Ministries is usually weak. In such cases it is proposed that a specified set of responsibilities and actions be passed on to the Ministry of Industry so that they exert direct control over the industry. In Bangladesh, the Small and Cottage Industries Corporation which licenses and regulates the functioning of salt producers and refiners, has been empowered with the implementation of the iodization programme and its monitoring at the production level. Retail and consumer level monitoring will have to be the responsibility of the Ministry of Health through the provincial and district-level health network.
Natural food sources of vitamin C (which enhances iron absorption) and vitamin A and, to some extent, iron, are inexpensive, culturally acceptable, and widely available. The trouble is that they are not given to the most vulnerable individuals, or storage is difficult, or they are unavailable seasonally. The most important dietary sources of these nutrients are dark green leafy vegetables, yellow and orange fruits and vegetables, legumes, and red meat. Some of these foods are cultivated and others are foraged. Among the cultivated foods are tree crops (fruits, red palm oil, and edible leaf trees), legumes, field crops (horticultural crops, leaves of tubers, and yellow fleshy tubers), and small stock. The foraged foods tend to be trapped or picked in uncultivated land and forests. These include wild fruits and berries, small animals, and green leaves.
For the cultivated foods, agricultural policies can send some powerful signals to farmers to encourage (or discourage) certain crops. Agriculture research and extension can make particular crops more profitable or feasible to cultivate. In Thailand, agriculture extension agents were used to distribute ivy gourd plants and to advise on its cultivation. When the so-called disease resistant crop developed insect and mould problems, modern scientists in collaboration with traditional herbal experts solved the problem. Horticultural crops generally require copious water and yield highly perishable products. Public policies which improve water availability and preservation and markets for perishable foods would help promote horticulture. In Mauritania, it was found that gardeners needed assistance with marketing surplus vegetables. Horticulture (as well as most field and tree crops) is usually promoted because of export or employment/income potential. Cash crops are useful for generating income but export vegetables may not be meeting local demand for micronutrient-rich foods. Both the crops themselves and the cultivation and processing methods may be different when locally-consumed vegetables are produced rather than exportable vegetables.
One area where agricultural policy has not been used extensively is in the encouragement of home gardens. Because these provide food primarily for home consumption, they may not have the status of marketed crops either to policy makers or to extension agents. They are usually women's domain and cultivated in more traditional ways which further denigrates their status. Home gardens can be both a major household food resource and a source of income. The Asian Vegetable Research and Development Center, affiliated with the Consultative Group on International Agricultural Research, has developed several garden designs which serve both nutritional and income generation purposes. Much more could be done to elevate the status and productivity of home gardens.
With foraged crops, the key policy issues relate more to land use and preservation of natural resources than to active cultivation. Forest land, meadows, wetlands, fallow land, and even weeds in cultivated fields have supplied traditionally much of the variety (and micronutrients) in people's diets. Many of these foods are unavailable in markets. From an environmental and nutritional standpoint, it is desirable to preserve these lands in the wild state or to encourage nearby communities to husband them wisely. In Nepal, when women were encouraged to manage their own forests, they were able to protect wild foods they depended on. Proper preservation of foods is particularly important for vitamin A which is often highly seasonal in its availability. In Haiti, mango preservation practices have been developed to spare the vitamin A content. Dried mango has developed as a local industry as well which generates income for women.
To support a diversified food base, food policies should be developed which give due weight to dietary quality, derivation of foods (particularly non-staple foods), and the overall trends in the food supply. In many countries, narrow policies to promote either food grains or export crops have reduced production of legumes, generally a good source of both protein and iron. A shift from sweet potatoes or yams to cassava may be seen as desirable from a calorie perspective or an adaptive response to high population density, but it has serious ramifications for vitamin A availability and, in the case of cassava, iodine nutriture. The destruction of forests can seriously limit nearby people's access to meat, edible leaves, and fruit. Monitoring and active policy intervention to reverse such negative trends are needed.
Demand for Micronutrients
In general, well-designed social marketing projects have achieved increases in amount and frequency of vitamin A-rich food consumption, as well as changes in attitudes, among target groups. These include a number of small projects in India and several regional projects in Asian countries. Experience in Indonesia, Bangladesh, Philippines, Nepal, and Thailand, suggests that dietary behaviour can be changed when communications strategies are designed appropriately. These programmes, all of which were oriented toward increasing intake of vitamin A-rich foods, show that consumers will improve their diets if given the proper incentives.
For use of food fortification, extensive testing of feasibility with manufacturers, and of acceptability of fortified food to consumers, is needed during the development of the product. Consumer testing on availability, price, taste, appearance, and differentiation from the unfortified product is critical to ensure that the fortified food will not meet significant consumer opposition. The fact that some fortified products are slightly off colour has been a deterrent to consumer satisfaction and must be examined closely prior to launch of the product. Likewise, when fortified salt is marketed at the same time as the unfortified, regular product, consumers must be informed and motivated because the new product is in direct competition with the old.
Where nutrients are accessible from fortified foods, consumer education is needed to motivate the consumer to purchase these foods. While technical manipulations are supposed to minimize the detectable difference between fortified and unfortified foods, occasional resistance to fortification is encountered because the fortificant is unnatural or chemical - witness of the resistance to fluoridation of water in the US. Sometimes fortified foods cost more than unfortified ones so consumer demand needs to be generated for the fortified product (this problem can be overcome by restricting choice via mandatory fortification of the chosen food and/or by providing incentives targeted).
Like fortification, pharmaceutical supplementation is often thought of as an easy solution since the product has already been developed. However, pill-taking or receipt of an injection often requires complex behaviour changes. Mothers in particular must make the effort to obtain and take or give supplements periodically or sometimes daily. Programmes need to communicate what the capsules, pills or injectables are, why they are important, who needs them (in what dosage and what frequency), when and where to get them, and what are their side effects. A common fear is that the iron pill or iodized oil injection is a contraceptive.
Supplementation with iron requires long-term, repeated behaviours. Evidence exists to show that even if pregnant women receive iron pills, they do not necessarily take them. Unpleasant side effects (dark stools, constipation, the fishy aftertaste of the pills), difficulty in maintaining a specific daily behaviour (pill-taking) over months, and rapid relief of symptoms (before anaemia is resolved) cause problems for compliance. A strong effort should focus on overcoming these problems.
Consumer demand for pharmaceutical sources of micronutrients (supplements) is important from two perspectives. First, if supplements are to be delivered through non-coercive means in the public health system, beneficiaries must present themselves at the appropriate time and place and accept the product offered. Where coverage of public health services is low it is particularly important to reach beyond the clinic with supplementation. This means generating a sense of entitlement to supplementation. If consumers do not demand the supplement, the health providers may forget to distribute it, the supplies are given to the non-needy or deteriorate in warehouses, and the programme is ineffective. Second, demand for supplements is subliminal because the intended beneficiaries either do not recognize deficiencies as diseases (fatigue is often a way of life - and not attributed to iron deficiency) or they may not know that their diet is the cause of the disease. Hence consumer information and motivation are both necessary.
Consumer demand for pharmaceutical sources of micronutrients can be high and expressed in private pharmaceutical markets. In developed countries, nutritional supplementation is a billion dollar industry. Even in traditional cultures and among low income groups, vitamins are sought out to cure diseases. These medications often in fact contain vitamins but they are sources of pseudonutrients as well: ineffective, falsely advertised, and potentially dangerous concoctions. Consumers, in addition, may take excessively high doses of nutrient supplements on the rationale that if a little bit is good, a lot is better. This overdosing may have toxic effects and most assuredly is a waste of money. Vitamin supplements of dubious value (especially injections of vitamin B complex) are over-prescribed by private and public providers and over-demanded by consumers while safe and efficacious (oral) micronutrient supplements that are needed for real nutritional deficiencies are often neglected. This is as much a problem of consumer education and physician self-regulation as it is of government regulation and the scruples of the pharmaceutical industry. The production, advertising and packaging of privately marketed micronutrient supplements needs to be tightly regulated and coupled with consumer education on the right pharmaceuticals (of the right potency with the proper frequency). An additional need is to train health care providers (public and private; traditional and modern) in proper diagnosis and treatment of micronutrient deficiencies.
Experience in Thailand provides useful guidance on programme evolution. Here, the general direction of the programme was established at the outset (addressing vitamin A deficiency through dietary means), but the means were developed as the programme developed and intended beneficiaries participated in it. In this iterative fashion, the beneficiaries and programme staff identified the focal food for promotion (ivy gourd), the means of promoting it, the most persuasive messages, and way of increasing availability of vitamin A foods. This last issue led them into agricultural promotion and extension.
One common characteristic of most successful programmes is the use of pilot projects and feasibility studies to try out delivery systems, communications concepts, and alternative sources of micronutrients. This experimentation, when combined with national advocacy and leadership, has led to revisions in programme design that were not anticipated initially, for example, the use of agricultural extension in Thailand. Information systems have facilitated further improvements as programmes have been implemented. In Ecuador, the process of development of the monitoring system identified both the highest risk groups and the roadblocks to achieving programme success. In fact it may not usually be possible (or desirable) to design a complete programme from the start. Flexible programme design is better complemented by experimentation, appropriate information systems, and consultation with intended beneficiaries helps generate effective and sustainable programmes. Equally clear is that national political support and long term donor commitment are required.
Targeting is a key consideration in designing a micronutrient supplementation programme because the deficiencies affect only a small portion of the population. Even in countries considered to have endemic vitamin A deficiency (India, Bangladesh, Indonesia), the prevalence of frank deficiency signs rarely exceeds 5% (in Bangladesh 2.6% of preschoolers were night-blind in 1991). With respect to iodine deficiency, an incidence of visible goitre in 20% or more of the population is a sign of a serious public health problem. Iron deficiency commonly affects 30% of the general population though as much as 75% of pregnant women. Clearly targeting is desirable if it can be done at low cost but in the case of iron the deficiency may be so prevalent that presumptive treatment of all pregnant or reproductive aged women may be more cost-effective. To date, vitamin A and mineral supplements have been targeted largely on the basis of geography, season, age and physiology. The options for targeting are listed below:
1. Universal targeting. Targeting vitamin A to all preschool children; targeting iron-folate tablets to all pregnant women; targeting iodized oil to all women of reproductive age.
2. Medical targeting. This includes targeting vitamin A to children with xerophthalmia, chronic diarrhoea, severe acute respiratory infections, growth failure, tuberculosis or measles deficiency; and targeting iron to premature and low birth weight babies.
3. Geographic or seasonal targeting. Iodized oil is usually targeted to high altitude areas and places beyond the reach of commercial salt markets. Vitamin A supplements may need to be given during only one season. Iron may be targeted to malarious or hookworm infected regions.
The option chosen depends critically on the nutrient concerned, the nature and extent of the deficiency, the coverage of the health system, and available resources. Where the deficiency is widespread and severe, universal coverage may be more cost-effective than selective coverage based on screening and/or giving the nutrient only to symptomatic or high risk individuals. Ideally, the health care system would provide the supplement on a regular schedule, just like immunizations (except that vitamin A needs to be given every 4-6 months and iodine needs to be given yearly). But most health systems are far from ideal and have low coverage rates. In these cases, micronutrients should be given (or targeted) on an opportunistic basis - whenever the child is seen by a health worker and had not received the nutrient in the past 4 months (in the case of vitamin A) or the past year (in the case of iodine), or whenever a reproductive-aged woman uses a health centre. Health cards for both mothers and children are needed to prevent overdosing with vitamin A or iodine. In addition, outreach activities will be needed where health system coverage is low. These could take the form of free standing campaigns (done in Indonesia, India and Bangladesh for vitamin A; and in Indonesia, Myanmar, China, Nepal and Zaire for iodine), or they could be linked with EPI activities (national immunization days). EPI campaigns, as currently configured, are better suited to iodine (which needs only one annual dose) than vitamin A because national campaign days are usually 2 days 4-6 weeks apart. With some expansion of responsibilities and target groups, however, EPI workers could be used to deliver vitamin A every 4-6 months or during specific months. In countries with highly seasonal deficiencies (like Nepal, for instance) a single dose, if properly timed, could be adequate. But in many countries, vitamin A deficiency is a year round problem.
Where vitamin A and iodine deficiencies are geographically, ethnically, or socio-economically concentrated, targeted rather than national programmes may be preferable (although emerging evidence on the effects of subclinical deficiencies suggests that broader targeting rather than narrow targeting may be warranted). It is fairly easy to delineate high risk areas based on iodine content in soils and water or goitre incidence in school children. These high risk areas often coincide with high altitude or flood plains. Vitamin A clusters less well geographically than iodine. One might use the incidence of blindness or the existence of local words for night blindness or, measles mortality as an indicator of vitamin A deficiency. While vitamin A risk may correlate with season or rainfall levels, this indicator is not specific enough for general application. Epidemiological data on vitamin A deficiency is likely to be needed. Elevated rates of blindness (if trachoma and onchocerciasis are not prevalent) would also be a warning of severe vitamin A deficiency.
Geographic targeting is most frequently used with iodine supplementation programmes. In Bolivia, Ecuador, Nepal, and Pakistan, iodine supplements are distributed to isolated mountain villages where iodized salt is unavailable. Because iodine supplements need to be delivered every one to three years, the burden on the health system is much less than that of vitamin A distribution which must be delivered two or three times per year. It is feasible to use vertical delivery teams or to use existing health staff to deliver the iodine. At the district level, perhaps multipurpose mobile teams could be used to deliver a series of periodic treatments (micronutrients, anti-helminthics, tetanus) including possibly growth monitoring.
Targeting can also be done on the basis of biomedical screening. From a medical perspective, it is preferable to screen clients before prescribing therapeutic treatment. In large scale national micronutrient programmes, however, the cost of screening far exceeds the cost of treatment. Where the prevalence of a deficiency is high enough to be a public health problem by WHO criteria, then presumptive treatment may be preferred. This is particularly true of iron supplementation of pregnant women. Toxicity becomes a potential problem with supplements when the nutrients become more replete in the population. In that case, community screening may be adequate - a sub-sample of people are selected and if the prevalence of the deficiency is high, all target-age individuals are supplemented.
In general, fortification is thought of as a universal programme, but targeted fortification is sometimes preferred. In Guatemala, the school-feeding programme uses a biscuit fortified with a number of vitamins and minerals. The biscuits are baked by local bakeries and the vitamin-mineral premix is distributed to them by the government. Undoubtedly the children in schools are a self-selected relatively privileged group but they profit educationally from the added nutrition. In South Africa, the Asian community was found to be the only sub-population that was iron deficient, so curry powder was fortified with iron. This was a highly self-targeted food which incurred no administrative cost to reach the intended beneficiaries. In Chile, and the US, infant foods are fortified with iron because that is one of the most vulnerable groups. One could also target fortification by fortifying foods consumed primarily by the poor.
Dietary change efforts, designed for specific groups and agri-ecological zones, are targeted by dietary pattern. It is the diet of the weaning-aged child or pregnant women that is usually targeted. This requires sensitivity to traditional beliefs and resistance points in developing messages.
Goals for the Year 2000
In September 1990, the World Summit for Children endorsed some challenging goals for micronutrients for the year 2000: virtual elimination of vitamin A and iodine deficiencies and a one-third reduction in iron deficiency anaemia in women. These goals were subsequently reaffirmed at the Ending Hidden Hunger policy conference in October 1991 and at the International Conference on Nutrition in December 1992. To achieve these goals will not be easy. It will require the combined efforts of governments, international organizations, NGOs and private industry. The central focus of activity over the next decade should be on
1. Raising consumer demand for micronutrients from natural food, fortified food or pharmaceutical supplements. Policy advocacy, social marketing and commercial advertising are effective in this.
2. Improving the effectiveness and coverage of pharmaceutical delivery systems including exploitation of new outreach mechanisms, better logistics, and improved client counselling.
3. Maximizing industry compliance with fortification mandates through incentives to private industry and through building objective, competent and respected regulatory enforcement institutions.