Strategies for Combatting Micronutrient Deficiency

STRATEGIES FOR COMBATTING MICRONUTRIENT DEFICIENCY

Micronutrient deficiency has been identified as a major underlying cause of numerous human health problems, particularly in developing countries. FAO estimates indicate that 840 million people (799 million in developing countries) do not receive enough energy from their diets to meet their needs. The global toll from micronutrient deficiency is even higher, with over 3 billion (nearly half of the world’s population) suffering from the effects of this deficiency, which has become known as the hidden hunger. Thus, while hunger is still a serious problem and should remain as a major concern, hidden hunger has occupied the center stage in the nutrition agenda.

Learning Objectives

After reading this chapter, you should be able to answer the following questions:

What are the world’s major micronutrient deficiencies?
What is being done to combat these deficiencies?

Major Micronutrient Deficiencies

Women and children in Africa, Asia, Latin American and the Caribbean are especially at risk of disease, premature death and impaired mental and motor development because of diets poor in crucial nutrients, particularly iron, vitamin A, iodine and zinc. Lack of vitamin A, iron and iodine are the three most widespread micronutrient deficiencies, commonly found among the economically poorest people, for which sociocultural and economic barriers restrict the consumption of balanced food.

Lack of iron is the most widespread nutritional disorder, affecting 2 000 million people, more than 750 million children. This deficiency causes an estimated 20% of maternal deaths and could be preventing 40-60% of children from growing to their full mental potential in developing countries. It is the most common cause of anemia, although anemia can also occur as a result of vitamin B12 or folate deficiencies, congenital hereditary defects in red cells, reproductive blood losses or from infection by malarial parasites or infestations of the gut by parasites such as hookworm.

Globally, about 3 million children of preschool age have visible eye damage due to vitamin A deficiency. Annually, an estimated 250 000-500 000 preschool children go blind from this deficiency and about two-thirds of these children die within months of going blind. Estimates of subclinical prevalence of vitamin A deficiency range from 100 to 250 million.

WHO estimates indicate that 741 million people or 13% of the world’s population are affected by goiter, but the most devastating consequence of iodine deficiency is reduced mental capacity. It is estimated that 100 000 children are born each year with irreversible brain damage because their mothers lacked iodine prior to or during pregnancy. Maternal iodine deficiency can also lead to spontaneous abortion, stillbirth and impaired fetal development.

Deficiencies in several other micronutrients, in particular zinc and folate, may also be widespread, with equally serious consequences for health.

There is no single solution to combat micronutrient malnutrition. Simultaneous implementation of interventions is needed and should be adapted to the particular needs and opportunities in each country. These strategies have been mostly developed for and applied to combat vitamin A deficiency. Few successful programs have been implemented to control iron deficiency in spite of its widespread prevalence.

In the case of iodine deficiency, the iodization of salt is the preferred solution; there are very few food sources of iodine. Key issues for iodized salt are distribution and marketing in remote areas and quality control of iodine content.

Promotion of Breastfeeding

Breast milk can supply the vitamin A that an infant needs for the first six months of life and can continue to be an important source through to the age of two years. Although vitamin A concentration in human milk depends on the mother’s vitamin A status, vitamin A deficiency is rare among breastfed infants, even in parts of the world where vitamin A deficiency is endemic. The promotion of exclusive breastfeeding for 4-6 months and continued breastfeeding with complementary foods thereafter is recommended as a part of any dietary intervention to improve vitamin A status.

Supplementation of High Risk Groups

Large-scale programs for periodic vitamin A supplementation for pre-school children in many developing countries have been reported not only to reduce clinical signs of vitamin A deficiency but also to reduce the mortality rate in children. Under these programs, children aged six months to five years are provided with high dose of vitamin A (100,000 international units for children 6-11 months and 200,000 international Units for children 1-5 years) usually in the form of capsule at six-month intervals. Supplementation (50,000 international units) is also recommended for non-breast-fed infants or breast-fed infants (less than 6 months old) whose mothers have not received supplemental vitamin A. To enhance the vitamin A status of the mother and the breast fed infant, supplementation in lactating mothers (200,000 international units within 8 weeks of childbirth) has been found effective.

Supplementation is an immediate and cost-effective measure to improve the vitamin A status of populations in which vitamin A deficiency is a serious public health problem. It should, however, be considered a short-term strategy that must be in place until food-based strategies (fortification and diet diversification) provide sufficient vitamin A intake.

Although conceptually simple, it has operational problems. It is often integrated in national immunization days to take advantage of the same structure, thus lowering operational costs and insuring high coverage. Nevertheless, irregular or inadequate supplies, budget constraints at the national level, poor orientation and low motivation of health workers and lack of supervision have been cited as causes of poor outreach of the program. Coverage varies widely and is often inadequate, with more remote areas being more difficult to reach and being often neglected due to poor infrastructure.

In contrast to vitamin A supplementation, iron supplementation has not been widely implemented. Iron supplements must be administered by mothers or caretakers daily over a sustained period. Thus, compliance is a critical issue, with women complaining about the difficulty of daily administration. Moreover, there are health risks associated with iron supplementation. It has to be administered with a lot of caution as it can be dangerous to sick, malnourished children. In malaria-endemic areas, supplements are not recommended in the absence of good malaria control and prevention program. There is some evidence that in the absence of this program, untargeted iron supplementation may increase child morbidity and mortality from malaria.

Food Fortification

In developed countries, fortification (the addition of essential nutrients to foods for prevention or correction of a dietary deficiency) is common and has contributed immensely to the reduction of micronutrient deficiency.

In the United States, the nearly complete eradication of overt vitamin deficiency diseases is taken as evidence of the exceptional effectiveness of fortification. There is concern that some nutrients might be consumed excessively. Thus, guidelines have been developed to avoid the indiscriminate addition of nutrients to foods. The American Medical Association-Institute of Food Technology-Food and Nutrition Board guidelines recommend the following prerequisites to justify fortification: (a) the intake of a particular nutrient is inadequate for a substantial portion of the population; (b) the food is consumed by most individuals in the target population; (c) there is reasonable assurance that excessive intake will not occur; (d) the cost is reasonable for the intended population. The joint statement also endorsed the continuation of the following practices: enrichment of flour, bread, degerminated and white rice with thiamin, riboflavin, niacin, iron and folic acid; restoration of thiamin, riboflavin, niacin and iron in processed cereal foods; addition of vitamin D to milk, fluid skimmed milk and nonfat dry milk; addition of vitamin A to margarine, fluid skim milk and nonfat dry milk; addition of iodine to salt; standardized addition of fluoride in areas in which the water supply has a low fluoride content.

Fortification has proven sustainable and successful in developed countries because of: (a) the presence of large, centralized food industries, (b) packing and labeling that facilitate monitoring and enforcement and (c) well-educated consumers who are aware of the value of adequate nutrition and have sufficient income to purchase the products.

Fortifying a widely consumed centrally processed food with critical nutrients can be a viable strategy to reduce the prevalence and severity of micronutrient deficiency in developing countries. Examples of vitamin A fortification programs are: fortification of sugar in Central America, margarine in the Philippines, monosodium glutamate in Indonesia and cooking oil in India. Various aspects of fortification should be addressed: selecting an appropriate vehicle and an adequate level of fortification to meet the requirements, along with stability, quality control and monitoring.

In a forum held in the Philippines in 2000 on food fortification policy for the protection of populations from mineral and vitamin deficiencies in Asia and the Pacific, the following consensus was reached: all people in the region should have access to affordable, safe and efficacious fortified foods as a long-term and permanent commitment to the elimination of micronutrient malnutrition; all salt intended for human consumption should be iodized; flour fortification with essential vitamins and minerals should be an integral part of all strategies to control and prevent malnutrition; fortification of staple foods like rice, cereals and oils as well as condiments and industrially processed complementary foods should be encouraged, particularly the fortification with iron, vitamin A, zinc and folic acid.

A food-based approach, including fortifying staple foods and condiments that are consumed by the entire population, is preferable and more sustainable for iron deficiency than supplementation. Fortification of cereal grains with iron is mandated in a large number of developed and developing countries. Included in this approach is home fortification, an example of which is a Canadian strategy presented in 1996: home fortification with Sprinkles, single-dose sachets containing micronutrients in a powder form. In Sprinkles, the iron is encapsulated within a thin lipid layer to prevent the iron from interacting with food, thereby limiting changes in taste, color or texture of the food. Caregivers are instructed to add the entire content of one sachet daily to any semi-solid food prepared for an infant or young child in the household, immediately before serving. Other essential micronutrients including zinc, iodine, vitamins A, C and D, and folic acid may be added to Sprinkles sachets.

Biofortification

A recent approach, complementary to existing strategies for the reduction of micronutrient deficiency in high-risk countries, is to fortify the major staple foods with micronutrients (e.g. rice and wheat with iron and zinc, sweet potato, cassava and maize with provitamin A), using the best traditional breeding practices and modern biotechnology. Called biofortification, this approach capitalizes on the regular daily intake of large amount of staples by all members of the family. It is intended to offer a sustainable and low-cost way to reach people with poor access to formal markets and health care systems in the developing world at a fraction of the recurring costs of either supplementation and fortification. Once the seeds are developed and distributed, farmers are expected to continue to grow the biofortified crop year after year. Agricultural productivity is not supposed to be compromised. A challenge is to get farmers and consumers to accept the biofortified crops and increase their intake of the target nutrient.

Biofortification efforts have initially focused on six staple crops: beans, cassava, maize, rice sweet potatoes and wheat. The potential for nutrient enhancement is also being examined in eleven additional crops important in diets of those suffering from micronutrient deficiencies: bananas, barley, cowpeas, groundnuts, lentils, millet, pigeon, peas, plantains, potatoes, sorghum and yams.

The production and consumption of orange-fleshed sweet potato, the result of efforts of plant breeders to select varieties with enhanced levels of beta-carotene using conventional methods, is being actively pursued in sub-Saharan Africa and elsewhere to address vitamin A deficiency.

Dietary Diversification

Although difficult to achieve because it requires universal access to adequate foods and appropriate dietary habits, regular intake of micronutrient-rich foods is the most sustainable, long-term solution to micronutrient malnutrition. Deficiency occurs in areas where the diet lacks variety, with inadequate amounts of fruits, vegetables and foods from animal sources that contain sufficient amounts of micronutrients. Thus, dietary diversification is being promoted, based on the increased production and consumption of foods rich in micronutrients to bring the intake into the range of recommended intakes. Contrary to single nutrient interventions, a varied diet provides various micronutrients and bioactive substances, thus having the possibility of addressing several deficiencies as well as prevention of chronic degenerative diseases.

Low consumption of fruits and vegetables has been shown to be due to lack of awareness and low availability of these foods at the household level. This led to a number of projects promoting the production and consumption of carotenoids-rich foods through home and school gardening, complemented by information, education and communication strategies. In order to be successful, gardening projects should be supported by nutrition education programs to raise awareness of the importance of micronutrients and consequences of their deficiency, assess dietary consumption, diversify food production, improve food preparation, processing, preservation, storage and marketing of micronutrient rich foods. The low bioavailability of plant provitamins A has led to the promotion of home or small scale production of fish, poultry and small animals to increase consumption of animal-derived foods rich in preformed vitamin A and bioavailable iron.

Diet diversification programs should take advantage of the diversity of local indigenous and traditional crops and wild plant species, which are often rich in nutrients and bioactive compounds, promoting their production, marketing and consumption. Dark green leafy vegetables are the most affordable sources of provitamins A; it also provides other nutrients and bioactive substances. Bioavailability of beta-carotene is low in these vegetables, but it can be increased by moderate cooking with a small amount of fat.

Complementary public health measures that help reduce micronutrient malnutrition should also be implemented, such as deworming, malaria prevention and control, improved water and sanitation facilities.

References

Badham, J., Zimmermann, M.B., Kraemer, K. (Eds.) (2007). The guidebook. Nutritional anemia. Sight and Life Press, Basel.

Bañuelos, G.S., Lin, Z.-Q. (Eds.) (2009). Development and uses of biofortified agricultural products. CRC Press, Boca Raton.

Berner, L. A., Clydesdale, F. M., Douglass, J. S. (2001). Fortification contributed greatly to vitamin and mineral intakes in the United States, 1989-1991. J. Nutr. 131: 2177-2183.

Butt, M.S., Tahir-Nadeem, M., Shahid, M. (2007). Vitamin A: Deficiency and food-based combating strategies in Pakistan and other developing countries. Food Reviews International 23: 281-302.

Dary O., Mora, J.O. (2002). Food fortification to reduce vitamin A deficiency: International Vitamin A Consultative Group Recommendations. J. Nutr. 132: 2927S-2933S.

Draper, A., Nestel, P. (Eds.) (2000). A study of factors influencing operational issues for iron supplements for infants and young children. ILSI Press, Washington D.C.

Kraemer, K., Zimmermann, M.B. (2007). Nutritional anemia. Sight and Life Press, Basel.

McLaren, D.S., Frigg, M. (2001). Sight and Life manual on vitamin A deficiency disorders (VADD), second edition. Task Force Sight and Life, Basel.

Nestel, P., Bouis, H.E., Meenakshi, J.V., Pfeiffer, W. (2006). Biofortification of staple food crops. J. Nutr. 136: 1064-1067

Reddy, V. (2002). History of the International Vitamin A Consultative Group 1975-2000. J. Nutr. 132: 2852S-2856S.

Ross, D.A. (2002). Recommendations for vitamin A supplementation. J. Nutr. 132: 2902S-2906S.

Solon, F. (2000). The Manila forum on food fortification policy. The potential for protecting populations from mineral and vitamin deficiencies in Asia and the Pacific. Sight and Life Newsletter 2: 27-28.

Sommer, A., Davidson, F.R. (2002). Assessment and control of vitamin A deficiency: The Annecy Accords. J. Nutr. 132: 2845S-2850S.

Thurham, D. (2011). Iron fortification – new revelations. Sight and Life 25: 44—54.

Toenniessen, G.H. (2002). Crop genetic improvement for enhanced human nutrition. J. Nutr. 132: 2943S-2946S.