It is now well established that the major damage caused by malnutrition takes place in the mother's womb and during the first 2 y of life. This damage is often irreversible and causes lower intelligence and reduced physical capacity, which in turn reduce productivity, slow economic growth and perpetuate poverty. Countries risk a “lost generation” unless they improve nutrition addressing both protein-energy and micronutrient needs for preschool children, the stage of life when the body and brain experience maximum growth and development potential.
Protein-energy malnutrition, resulting in people being underweight or stunted, and micronutrient malnutrition continue to be major health burdens in developing countries. Such malnutrition prevents as many as one third of the world's people from reaching their physical and mental potential. Malnutrition combined with a poor diet and infectious disease forms a vicious cycle, with 1 condition affecting the others. Consequently, malnutrition is the most important risk factor for the burden of disease in developing countries and is directly and indirectly responsible for about half of all deaths in young children (1). Although higher incomes and better food security improve nutrition over the longer term, malnutrition is not simply the result of food insecurity; many children in food-secure environments are underweight or stunted because of inappropriate infant feeding and care practices, poor access to health services or poor sanitation. Child nutrition is an essential element in human development and is best improved in the context of coordinated investments in primary health care and early and basic education.
Much more attention, therefore, needs to be given to the betterment of nutrition via an integrated combination of health and nutrition education, improved dietary intake, supplementation and commercial and home-based fortification of complementary foods and staple foods more broadly. There are proven and cost-effective methods available that can greatly accelerate the improvement in nutrition. In addressing malnutrition, a combination of interventions involving the promotion of breast-feeding, improving food availability and micronutrient bioavailability and increasing food consumption, food fortification and pharmaceutical supplementation will need to be emphasized and implemented in a complementary manner. These factors need to go well beyond conventional health and nutrition systems and be based upon enabling people and communities so that they will be capable of arranging for and sustaining an adequate intake of micronutrients, independent of external support. Strategies are necessarily multisectoral and integrated interventions with strong social communications, evaluation and surveillance components.
Optimally, we should be able to meet nutrient requirements through the food we eat. Maybe we will reach that goal one day, but we are not there yet. For several reasons—economic, geographic, social and cultural—this has not been a practical solution, and even if this were possible there are issues related to the lack of bioavailable minerals and vitamins from staple diets. This inability to meet energy requirements is exacerbated by commonly consumed foods and beverages, including rice, wheat, corn, legumes, tea and coffee being high in inhibitors and low in enhancers of micronutrient absorption. The objective of this review is to identify successful and effective interventions to alleviate malnutrition in preschool children.
ADDRESSING MALNUTRITION THROUGH COMMUNITY-BASED PROGRAMMES
The best window of opportunity for addressing malnutrition lies between pregnancy and 2 y of age. Improving maternal knowledge and care during pregnancy to address low birth weights, especially in Asia, and infant feeding and caring practices, such as exclusive breast-feeding and adequate and timely complementary feeding, are critical to improving nutrition outcomes. Well-designed and consistent nutrition education approaches aimed at changing specific practices are key. In addition, because moderate and mild malnutrition are not readily apparent, regular monitoring of children's weights on a growth chart is important so that mothers know whether their children are growing properly and can see the benefits of changes in practices.
During the past 20 y successful programmes have been developed in several countries using a combination of nutrition education or counselling, either with or without growth monitoring, especially about maternal care and rest during pregnancy; exclusive breast-feeding and appropriate complementary feeding practices; education on how to care for sick children; and links to essential health services. Some programmes have also provided micronutrient supplements and/or food supplements for children and pregnant and lactating women; this, however, implies there is a need for good training and fostering counselling skills. The programmes are targeted to children <2 y of age. Successful, large-scale child growth promotion programmes were established in the 1980s in India's Tamil Nadu state, Indonesia and Thailand, and are ongoing in Bangladesh, Honduras, Madagascar and Senegal, among others. Such programmes led to a sharp decline in severe malnutrition in the first 1 to 2 y, with a slower rate of decline in moderate and mild malnutrition thereafter. A recent cross-country review of successful programmes concluded that they led to an average decline of 1 to 2 percentage points per year in rates of malnutrition in young children, 2 to 4 times the 0.5% rate calculated as the average secular trend in the absence of such programmes (2).
Malnutrition in young children is also being addressed in several countries through facility-based services such as the Integrated Management of Childhood Illness Program, developed in 1992 with the aim of prevention or early detection and treatment of the leading childhood killers. Although these programmes focus on treatment of childhood illnesses, they also emphasize prevention of illness through education on the importance of immunization, micronutrient supplementation, and improved nutrition, especially breast-feeding and infant feeding (3).
Oral supplements in capsule, tablet or syrup form provide immediate relief to vulnerable populations and age groups with special micronutrient needs (eg, pregnant and lactating mothers, preschool children). Certain micronutrients, such as vitamin A, can be provided as high-dose supplements twice per year. Most other vitamins and minerals (eg, iron, zinc, iodine) need to be provided in daily doses. In some cases supplementation for women during adolescence and through the childbearing years, especially during pregnancy, needs to be continued indefinitely.
A clear success story is the improvement in the vitamin A status of preschool children using high-dose supplementation. Vitamin A supplements lend themselves to distribution through a campaign approach because children require only 2 annual doses. Vitamin A supplementation (VAS) has been associated with a reduction in excess mortality of up to 35% among preschool children in populations in which vitamin A deficiency is endemic. In 1998 the World Health Organization recommended administering VAS with routine and other immunization contacts as a way of integrating provision with other health services. As National Immunization Day campaigns became widespread, many countries integrated VAS and oral polio vaccine distribution, enabling large numbers of children to receive at least 1 VAS dose annually. At least 90 countries routinely provide vitamin A supplements to young children in developing countries. More than 75% of all young children in countries where vitamin A deficiency is known to be common received high-dose vitamin A capsules in 2002, compared to only about one third in 1994 (4). Countries as different as Nicaragua (5), Niger (6) and Nepal (7) have reached coverage levels >80%.
A good example that clearly establishes the effectiveness of VAS is Nicaragua, where coverage has gradually increased in both rounds since 1994 and levels >70% have been sustained since 1999, with levels >80% since 2003. The average coverage rate by round from 1997 to 2001 amounted to 79% in first rounds and 78% in second rounds. The latter is a remarkable achievement because obtaining high second round coverage rates has been a formidable challenge for many countries. Only 1% to 2% of the total coverage has been achieved through non-national health campaign routine health service distribution. A 2000 National Micronutrient Survey carried out about 4 months after the second health campaign of 1999, revealed a dramatic reduction (72%) in the prevalence of vitamin A deficiency in children 12 to 59 mo of age, from 31.1% in 1993 to 8.6% in 2000 (8). This significant improvement may be mostly attributed to the cumulative effect of VAS as a result of the consistently high coverage rates in children over the 6-y period preceding the survey, given the absence of other specific interventions during the same period. Successive rounds of supplementation may have gradually increased serum retinol levels over time.
As polio National Immunization Days phase out, or in some cases terminate abruptly, there is a need to develop alternative delivery mechanisms to ensure that VAS reaches all eligible children twice each year. (Recent assessments by UNICEF and the Micronutrient Initiative have found that many countries are working to implement integrated packages of health services for their populations, and phasing out “vertical programmes,” including stand-alone VAS distribution [unpublished data, 2004].) Governments and international institutions are turning to alternative supplement delivery channels as a means of sustaining these gains (eg, piggybacking on the Day of the African Child, World AIDS Day in Tanzania [H. Masanja et al., unpublished data]) or creating twice-yearly national micronutrient days, following the Philippines' and Niger's examples. Clearly,VAS must be more closely integrated with other interventions such as deworming, malaria prevention, and antenatal checks. The challenge is thus to ensure not only adequate reach with such packages but also to integrate VAS into protective child survival and health services in a sustainable manner.
Iron supplementation has proved more challenging than VAS because the supplement must be taken daily and sometimes has unpleasant side effects; consequently, there have been problems with the logistics of supply and sometimes with compliance among clients. As a result 40% to 60% of the children in most developing countries continue to suffer from iron deficiency anaemia and many more have functionally significant iron deficiency. Prevalence rates are particularly high and devastating in their functional consequences for children ages 6 mo to 2 y, when the brain is continuing to grow. Indonesia and Thailand are among the few developing countries that have made the most progress in reducing anaemia. In Thailand between 1986 and 1996, anaemia prevalence in pregnant women fell from 40% to 15.5% and anaemia in children <5 y old declined from 40.6% to 25.2%. Based on such successes, guidelines have been developed to guide effective iron supplementation programmes and replicate proven programme models (9).
In settings where the risk of zinc deficiency is high and where other strategies may be difficult to implement in the short term, the distribution of zinc supplements as prophylaxis may be considered. The efficacy of supplemental zinc to improve specific health outcomes among high-risk population groups has been well demonstrated in a variety of geographical settings. However, country-level assistance is required for the design and integration of zinc supplementation strategies within existing health programmes (10).
Given the multiplicity of deficiencies, the idea of providing multiple micronutrient supplements for infants and preschool children is appealing. More research is needed to identify both physiological and health outcomes and the relative value of alternative micronutrients and potential competition between them, from absorption to physiological outcome.
Food fortification involves the identification of commonly eaten foods that can act as vehicles for ≥1 micronutrients and lend themselves to centralized processing on an economical scale. Fortification, when imposed on existing food patterns, may not necessitate changes in the customary diet of the population and does not call for individual compliance. It can often be dovetailed into existing food production and distribution systems. For these reasons, fortification can often be implemented and yield results quickly and be sustained over a long period of time. It can thus be the most cost-effective means of overcoming micronutrient malnutrition. The World Bank has reported that “No other technology offers as large an opportunity to improve lives at such low cost and in such a short time” (11). Food fortification is aimed to provide meaningful levels of the nutrient, usually 30% to 50% of the daily adult requirements, at normal levels of consumption of the food vehicle. The levels also need to take into account variations in food consumption so that the safety of those at the higher end of the scale and impact on those at the lower end are ensured. They should also consider prorated intakes by young children to ensure efficacious and safe dosages.
The most successful global fortification experience is the fortification of salt with iodine. A number of countries have successfully iodized their salt supplies, thus reducing goiter and cretinism, preventing metal retardation and subclinical iodine deficiency disorders, and contributing to improving national productivity. There has been remarkable growth in salt iodization application globally during the past decade. A significant proportion of the populations in more than 110 countries have access to iodized salt (12). As of 2004 nearly two thirds of the salt consumed in the developing world is being iodized, protecting nearly 70 million newborns each year from the threat of mental impairment caused by iodine deficiency.
Many countries are progressing toward the goal of universal salt iodization. Most of the salt used for human and animal consumption in Latin America is iodized. Bolivia, Peru and Ecuador, formerly severely affected countries, are now free of iodine deficiency. In many Asian countries, including Bangladesh, China, Indonesia and India, salt iodization is rapidly gaining ground. In sub-Saharan African countries including Nigeria, Madagascar, Eritrea and Cameroon, salt iodization levels are >80%. Once established in a country, salt iodization is a permanent and long-term solution to the problem of iodine deficiency. Toxicity issues are negligible and cost considerations fairly small, amounting to only 1 to 3 cents per person per year. Although considerable progress has been made in streamlining control programmes through salt iodization in several countries, producer compliance, quality assurance, logistic problems and bottlenecks remain. The challenge is to systematically identify and tackle these constraints through effective advocacy, social communications, monitoring of salt iodine levels, regulation and enforcement. Salt, which forms the ubiquitous part of our diets, can also carry a range of other nutrients including iron, zinc and vitamin A.
Fortification of other staple foods such as flour, oils, sugar, condiments, dairy products and a range of processed foods with other minerals and vitamins is also growing in the developing world. Potential food vehicles can be visualised as a 3-tiered pyramid (Fig. 1).
Fortifying less expensive staple foods at the base of the pyramid results in broader dissemination of micronutrients throughout the population, particularly in the poor. Also, because basic and value-added foods are processed from staple commodities, fortifying foods at the base of the pyramid results in fortifying products throughout the food chain. Often a period of voluntary fortification needs to be followed by mandatory requirement to ensure full compliance and sustained impact.
Cereals are important food vehicles for fortification. Although several foods could be used for carrying micronutrients, wheat flour and maize meal are excellent vehicles because they are staple foods in many parts of the world and exist as key ingredients in so many food preparations. When micronutrient deficiencies are population-wide and result from a combination of low intake and/or low bioavailability, fortification of commonly consumed cereal flours with iron, folic acid and other vitamins offers a number of strategic advantages because cereals flours are widely and regularly consumed, and mostly processed in centralized facilities with established distribution and marketing capacity. Costs of fortification range from 3 to 10 cents per person per year. For these reasons cereal fortification has played a major role in improving the health of the world populations at large. Nearly 40 countries now fortify flour. In Latin America flour fortification covers significant numbers of people and sugar fortification has taken hold in Central America. There is growing interest and action on wheat flour fortification in south and southeast Asia. In Africa the fortification of wheat and maize flours with multiple nutrients has been made mandatory in South Africa and Nigeria.
Folic acid fortification of cereal flours is having a remarkable impact on reducing women's risk of having a baby born with spina bifida or anencephaly. Food fortification was determined to be the best strategy for increasing blood folate levels because the critical period for adequate intake of folic acid is in the first weeks of pregnancy, before most women know that they are pregnant and begin taking supplements. In the United States the fortification of enriched cereal grain products with folic acid began in 1996. By 1999 the National Health and Nutrition Examination Survey conducted by the Centers for Disease Control and Prevention found that the average level of folic acid in the blood of US women of childbearing age had almost tripled in 5 y (13). In Canada, where fortification of flour, pasta and cornmeal became mandatory in 1998, a study in Ontario showed that the incidence of neural tube defects had fallen to 8.6 cases/10,000 pregnancies, down from 16.2/10,000 in 1995 (14).
Developed countries have long fortified milk and breakfast cereals with vitamin A as well as other vitamins and minerals, but in developing countries sugar has so far been the most successful vehicle. Guatemala's sugar fortification programme has virtually eliminated vitamin A deficiency. Significant reductions have also been noted in El Salvador and Honduras, where fortification was combined with supplementation (15). Sugar fortification and VAS were also combined in Zambia beginning in 1998, with demonstrated success in urban areas (16). In much of Africa and Asia the poor do not consume as much sugar as they do in Latin America, however, so other countries such as Nigeria, Morocco, Yemen, Bangladesh and Pakistan are experimenting with fortifying wheat flour or cooking oils with vitamin A.
FORTIFICATION OF COMPLEMENTARY FOODS
The fortification of commercially marketed staple foods such as cereal flours, cooking oils and dairy products could have a small but significant impact on preschool children. (Infants and children under the age of 24 mo consume a different dietary pattern than do older individuals.) There are no major differences in consumption among children ages 2 y and older. Industrially produced fortified complementary foods are recommended by pediatricians worldwide as an essential part of a nutritionally adequate infant diet beyond the age of 6 mo and are complementary with breast milk and home-prepared foods. Fortification, especially of iron and zinc, is essential to meet the micronutrient requirements of infants. Beyond the superior micronutrient content of industrially fortified complementary foods over home-prepared rice porridge and other traditional infant foods, this approach possesses advantages of delivering micronutrients of higher bioavailability, higher energy density and protein quality, not to mention safety and convenience.
From the food technology perspective, the challenge is to increase both the energy density of complementary foods and levels of micronutrients at an affordable price. From the public health perspective, we need a combination of proper regulation that protects infant health yet supports industrial innovation and strong public education on appropriate infant feeding practices and psychosocial care of the infant.
TARGETED FORTIFICATION THROUGH SUPERVISED PUBLIC PROGRAMMES
Fortification of foods that are targeted to vulnerable and low-income groups needs high priority. There are several opportunities in developing countries that if taken advantage of and applied could make a vast difference to millions of people suffering from micronutrient deficiencies.
Fortified complementary foods provided through public feeding programmes and commercially marketed foods have also had a positive impact. In some states in India food provided to children and to mothers under the Integrated Child Development Scheme in cooked or ready-to-eat form is micronutrient enriched. In Ecuador the Ministry of Public Health developed a complementary feeding programme that sought to prevent poor growth, anaemia, and other micronutrient deficiencies by targeting all infants and young children between 6 and 24 mo of age living under conditions of extreme poverty by providing micronutrient-fortified complementary foods such as Mi Papilla specifically designed to meet their unique nutritional needs (17). It contracted the production and distribution of the food to a private company through a competitive bidding process. This enabled the health workers to focus on providing health services and nutrition counseling. During health center visits for well- or sick-child care, coupons for the fortified complementary food are provided to eligible children. Mothers or caregivers can redeem these coupons for Mi Papilla at a nearby pharmacy or store selected by the community as the distribution point. At the final survey, the hemoglobin levels in children in the programme group were significantly higher and they were significantly less likely to be anemic compared with children in the nonprogramme group (27.6% vs 44.3%).
In Mexico under the Progresa programme, a large incentive-based development programme that today reaches 4.5 million families and included a nutritional component, children and pregnant and lactating women in participating households received fortified nutrition supplements, and the families received nutrition education, health care, and cash transfers. Progresa was associated with better growth in height and haemoglobin values among the poorest and younger infants (18).
Nutrition interventions are also an important component of social planning in Chile. Since the 1950s, the National Supplementary Food Program administered by the Chilean Ministry of Health through primary care health centres has provided free milk-based complementary foods to children from birth to 5 y. The monthly health care programme, which includes growth and development monitoring, breast-feeding promotion and immunization and education in nutrition, is offered in conjunction with the National Supplementary Food Program. Since 1999 the programme has delivered free of cost 2 kg/mo of a full-fat powdered milk to 70% of infants from birth to 18 mo. Lactating mothers consume this milk until their infants are weaned. The milk is fortified with iron, ascorbic acid, zinc and copper. The programme has helped reduce anaemia in Chilean infants from 21% to around 1% (19).
Where fortified foods are not available, there are multiple ways to deliver micronutrients to enable mothers to either add them to the cooking pot or to mix them into what they feed their infants. These food supplements are available as water-dispersible or crushable tablets, sprinkles or spreads that can be added to complementary foods just before feeding infants and young children. These supplements are designed to provide up to the full level of the Recommended Dietary Allowance for vitamins and minerals in a small volume at a low cost and are easily integrated into existing food practices.
Fortified lozenges, containing a combination of vitamins and minerals: vitamin A, vitamin C, zinc, iron and folic acid, offer a new approach to providing micronutrients to beneficiaries who are children between 2 and 5 y, adolescent girls and pregnant and lactating mothers. In India lozenges are distributed to children and mothers on a daily basis along with the regular supplementary food provided through the Integrated Child Development Scheme. The distribution is supported by a strong communications component imparted to the mothers. Some advantages of this approach are that distribution is simple, measured quantity of micronutrients can be ensured and compliance is high.
MICRONUTRIENT-RICH STAPLE FOODS
Breakthroughs in plant breeding and nutritional genomics could simplify and hasten the development of nutrient-rich varieties of crops. New efforts to enhance the micronutrient content of staple foods such as rice, maize, sweet potato, cassava, common beans and wheat that are consumed by poor people in developing countries through plant breeding are showing promise. Advanced biotechnology tools, such as genome mapping and marker-assisted selection, could enable us to identify, select, and transfer desirable traits, including those linked to high micronutrient content for nutrients such as iron, zinc and β-carotene, from 1 variety to another with or without transfer of genes across species (20). By producing plants that are dense in minerals and vitamins, a process referred to biofortification, we could have crop varieties with improved nutritional content in the staple foods people already eat. This can be a feasible means of reaching malnourished populations in relatively remote rural areas with limited access to health programmes through which supplements are channelled or to commercially marketed fortified foods.
Research so far has focused on 5 crops: rice, wheat, maize, cassava and common beans and 3 nutrients: iron, zinc, and β-carotene. For all of these crops, there is adequate genetic variation in concentrations of β-carotene, other functional carotenoids, iron, zinc, and other trace minerals in varieties available in germplasm banks to increase micronutrient densities through conventional breeding by a multiple of 2 for trace minerals and by higher multiples for vitamin A. A new 10-year challenge programme of Consultative Group on International Agricultural Research known as Harvest Plus proposes to further increase the micronutrient content of these crops through conventional breeding, test their nutritional efficacy and then widely disseminate them in developing countries for adoption by farmers.
DELIVERY AND SUSTAINABILITY
A key need is to deliver and distribute micronutrients to remote and impoverished populations in an affordable and sustainable manner. Government commitment, clear policy and programme direction, advocacy and communication combined with a strong public–private partnership is essential for successful programmes. We have also realized that addressing malnutrition cannot happen through stand-alone vertical programmes. We have also become much more effective in inserting nutrition into broader health and social development goals, rather than wait for them to be addressed to serve the cause of nutrition. We must focus increasingly on intersecting micronutrient programmes with major development challenges. These challenges include HIV/AIDS, malaria, hookworm and reproductive health and emergency programmes. In addition, nutrition should be included on the agenda of important reproductive and child health initiatives. Vitamin A deficiency should be placed on the agenda of ophthalmologists. Similarly, iron deficiency needs to become a priority in early child development, school health and maternal health programmes.
A programming environment is emerging globally and at the individual country level. The move from projects to programmes, from financing and implementing vertical disease-specific projects to sector-wide approaches and budget support, as well as a reinvigorated focus on multisectoral action, poverty reduction and issues of equity, are part of this new environment. The role of civil society and the private sector is becoming more important in global health and nutrition. At the same time, focus on results has never been higher on the agenda of both development partners and developing countries. These changes call for new approaches in moving the nutrition agenda forward, accelerating the move from project to more coordinated programme approaches, repositioning nutrition appropriately in country-development strategies, reorienting existing large-scale investments to maximize impact and improving implementation quality.
It is often said that malnutrition persists because of a lack of an expert consensus on its assessment and treatment coupled with weak policies and ineffective programmes. These are only partial reasons. In the wider picture technological problems are not nearly as serious as operational ones related to making programmes work in communities where malnourished people live. Issues of demand, supply and logistics, communications and community participation, partnership building across a wide spectrum of players, both public and private, are equally important to ensure the success and sustainability of efforts to eliminate malnutrition in large populations. Many of these needs interact and are mutually reinforcing.
The reality is that policymakers are faced with overwhelming development challenges and limited resources to address them. Pathogenic environmental mycobacteria or micronutrient deficiencies are rarely at the top of the policy agenda. It is our task, therefore, to demonstrate to policymakers that with a small investment in micronutrition, countries can make tremendous inroads in reaching a number of other development goals including reducing infant and maternal mortality and building up health and immunity to infectious diseases. Through these actions the burden on the health care system can be reduced, improving the ability of children to benefit from education and school programmes in later years.
The time is right for a rededicated initiative to eliminate the global malnutrition problem. We have new technologies, improved communications, and an expanded public infrastructure through supervised feeding programmes. In parallel, by demanding the supplements and fortified foods that they need, consumers enable themselves to achieve their full social, physiological and economic potential. By eliminating malnutrition through complementary public-private-civic sector initiatives we can make an enormous difference to the health and well-being of millions of children around the world.
1. Black RE, Morris SS, Bryce J. Where and why are 10 million children dying every year? Lancet 2003; 361:2226–2234.
2. Mason J, Galloway R, Martines J, et al. Community health and nutrition programs. In: Jamison D, Breman J, Claeson M, et al., eds. Disease Control Priorities in Developing Countries
, 2nd ed. New York: Oxford University Press for the World Bank.
3. Armstrong Schellenberg JR, Adam T, Mshinda H, et al
. Effectiveness and cost of facility-based integrated management of childhood illness (IMCI) in Tanzania. Lancet 2004; 364:1583–1594.
4. UNICEF and The Micronutrient Initiative. Vitamin & Mineral Deficiency. A Global Progress Report. New York: United Nations, 2004.
5. Mora JO, Bonilla J. Successful Vitamin A Supplementation in Nicaragua. Newsletter 3. Washington, DC: MOST (United States Agency for International Development Micronutrient Program), 2002.
6. Aguayo VM, Baker SK, Crespin X, et al. Maintaining High Vitamin A Supplementation Coverage in Children. Lessons from Niger. Nutrition in Development Series; Issue 5. Dakar-Yoff, Senegal: Helen Keller International Africa, 2005.
7. Fiedler JL. The Nepal national vitamin A program: prototype to emulate or donor enclave? Health Policy Plan 2000; 15(2):145–156.
8. Mora JO, Bonilla J. In: The Nicaragua VAS Report: Successful Vitamin A Supplementation in Nicaragua. Newsletter 3, Frigg M, ed. Basel, Switzerland: Sight & Life, 2002; 75–80.
9. Galloway R. Anemia Prevention and Control: What Works. Geneva: Food and Agriculture Organization/Micronutrient Initiative/Pan American Health Organization/UNICEF/U.S. Agency for International Development/World Bank/World Health Organization, 2003.
10. International Zinc Consultative Group. Assessment of the risk of zinc deficiency in populations and options for its control. Food Nutr Bull
11. The World Bank. Enriching Lives: Overcoming Vitamin and Mineral Malnutrition in Developing Countries. Development in Practice Series. Washington, DC: The World Bank, 1994.
12. UNICEF. The State of the World's Children. New York: UNICEF, 2004.
13. Charatan F. Fortification of flour likely to halve neural tube defects, says CDC. BMJ 1999; 318:1506.
14. Gucciardi E, Pietrusiak M, Reynolds DL, et al
. Incidence of neural tube defects in Ontario, 1986–1999. CMAJ 2002; 167:237–240.
15. Mannar V, Shankar R. Micronutrient fortification of foods—rationale, application and impact. Indian J Pediatr 2004; 71:997–1002.
16. Serlemitsos JA, Fusco H. Vitamin A Fortification of Sugar in Zambia, 1998–2001. Washington, DC: MOST (United States Agency for International Development Micronutrient Program), 2001.
17. Lutter C. Effectiveness of Ecuador's National Fortified Complementary Food Program for Children Under 5 Years of Age (PANN 2000). Washington, DC: Pan American Health Organization, 2004.
18. Rivera JA, Sotres-Alvarez D, Habicht JP, et al
. Impact of the Mexican Program for Education, Health, and Nutrition (Progresa) on rates of growth and anemia in infants and young children. A randomized effectiveness study. JAMA 2004; 291:2563–2570.
19. Torrejon CS, Castillo-Duran C, Hertrampf ED, et al
. Zinc and iron nutrition in Chilean children fed fortified milk provided by the Complementary National Food Program. Nutrition 2004; 20:177–180.
20. International Food Policy Research Institute. Harnessing Agricultural Technology to Improve the Health of the Poor: “Biofortified” Crops to Combat Micronutrient Malnutrition. Proposed as a Challenge Program of the CGIAR, 2002.