Magnitude, causes and consequences of micronutrient malnutrition
Measures to prevent and control micronutrient malnutrition
Micronutrient malnutrition is a term used to refer to diseases caused by a dietary deficiency of vitamins or minerals. More than 2 billion people in the world today may be affected by Micronutrient malnutrition. Vitamin A deficiency, iron deficiency anaemia and iodine deficiency disorders are the most common forms of Micronutrient malnutrition. People of all population groups in all regions of the world can be affected by Micronutrient malnutrition (Table 1). Although the most severe problems of Micronutrient malnutrition are found in developing countries, people in developed countries also suffer from various forms of these nutritional problems.
Table 1. Estimated numbers of people (in millions) at risk and affected by the three main forms of micronutrient malnutrition.
Iodine Deficiency Disorders1 |
Vitamin A Deficiency*2 | ||||
Region |
At Risk |
Affected(Goitre) |
At Risk |
Affected(Xerophthalmia) |
Iron deficient or Anaemic3 |
Africa |
181 |
86 |
52 |
1.0 |
206 |
Americas |
168 |
63 |
16 |
0.1 |
94 |
South-East Asia |
486 |
176 |
125 |
1.5 |
616 |
Europe |
141 |
97 |
- |
- |
27 |
Eastern Mediterranean |
173 |
93 |
16 |
0.1 |
149 |
West Pacific |
423 |
141 |
42 |
0.1 |
1058 |
TOTAL |
1572 |
655 |
251 |
2.8 |
2150 |
Estimates for vitamin A deficiency are for children from birth to five years of age.
1WHO/UNICEF/ICCIDD (1994). 2WHO/UNICEF (1995). 3WHO (1992).
Micronutrient malnutrition is a major impediment to socioeconomic development and contributes to a vicious circle of underdevelopment, to the detriment of already underprivileged groups. It has long-ranging effects on health, learning ability and productivity. Micronutrient malnutrition leads to high social and public costs, reduced work capacity in populations due to high rates of illness and disability, and tragic loss of human potential. Overcoming Micronutrient malnutrition is a precondition for ensuring rapid and appropriate development.
Poverty, lack of access to a variety of foods, lack of knowledge of optimal dietary practices and high incidence of infectious diseases are some of the factors which lead to Micronutrient malnutrition. Policies and programmes must be developed to assure availability of and access to an adequate variety and quantity of safe, good-quality foods for all people of the world.
Vitamin A deficiency (VAD) primarily affects children; worldwide, some 250 million children are at risk (WHO 1992). It causes night blindness and, eventually, permanent blindness (xerophthalmia). It also contributes to retarded physical growth and impaired resistance to infections, resulting in high rates of sickness and death among young children. Every year, a quarter to half a million children go permanently blind as a result of VAD; two-thirds of these are likely to die. Regular consumption of vitamin A-rich foods such as animal products, orange and yellow fruits and vegetables, dark green edible leaves, and palm oil could prevent VAD.
Anaemia and iron deficiency affect more than 2 billion people in virtually all countries (WHO 1992). Those most affected are women and pre-school-age children (as many as 50 percent of whom may be anaemic), but anaemia is also seen in older children and men. Anaemia in infants and children is associated with retarded physical growth, reduced resistance to infections and slow development of learning abilities. In adults it causes fatigue and reduced work capacity and may cause reproductive impairment.
Blood loss in childbirth is very dangerous for anaemic women and is the main cause of about 20 percent of maternal deaths. Maternal anaemia also leads to foetal growth retardation, low infant birth weight and increased perinatal mortality (death in the first week of life). Foods such as dark green leafy vegetables, legumes and red meat are rich in iron, as are iron-fortified food products. However, because of the low bioavailability of iron in plant foods and the high cost of red meat, prevention and cure of iron deficiency anaemia is not an easy task, even in developed countries.
Iodine deficiency disorder (IDD) is a threat to more than 1.5 billion people who live in areas where the soils are iodine deficient; more than 200 million people have goitre and 20 million suffer mental impairments (resulting in significant reduction in IQ) caused by iodine deficiency (WHO 1992). IDD is the most common cause of preventable mental retardation. In severe cases it leads to deaf-mutism, cretinism and other serious disorders, as well as reproductive impairment, which results in increased rates of miscarriage, stillbirth and birth defects. Some seafoods are good sources of iodine and adding iodine to salt is a common and effective method of preventing IDD.
Despite its link to poverty, not all micronutrient malnutrition will simply disappear as development occurs. Moderate levels of IDD still exist in some high-income European countries which have failed to take adequate measures to eliminate it on a sustainable basis.
Effective methods exist to overcome micronutrient malnutrition, but they require concrete, comprehensive, cost-effective efforts by governments to be successful. The unnecessary human suffering and hindrance to economic development caused by micronutrient malnutrition can be eliminated in large part by improving the nutritional quality of the food supply and by educating people about good dietary practices.
Vitamin A deficiency, often in association with protein-energy malnutrition, principally affects preschool children. It is estimated that almost 250 million children in developing countries are at risk, of whom at least 2.8-3 million are clinically deficient. This Thai fruit vendor's child (see picture) is fortunate to have access to vitamin A-rich mangoes and other micronutrient-rich foods. Pre-school-age children and adolescent girls, along with women of child bearing age, are especially prone to iron deficiency anaemia, which affects over 2000 million people worldwide. Iodine deficiency disorder is also widespread, with 1500 million people in the world at risk.
Thai fruit vendor's child
Four main strategies - dietary improvement, including increased production and consumption of micronutrient-rich foods; food fortification; supplementation; and global public health and other disease control measures - can be implemented to overcome micronutrient malnutrition. Food-based strategies, which include food production, dietary diversification and food fortification, are the most sustainable approaches to increasing the micronutrient status of populations. These approaches not only prevent micronutrient deficiency problems but also contribute to general malnutrition prevention.
At the International Conference on Nutrition (ICN), jointly convened by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) in December 1992, representatives of 159 countries endorsed the World Declaration on Nutrition, pledging "to make all efforts to eliminate before the end of the decade... iodine and vitamin A deficiencies" and "to reduce substantially... other important micronutrient deficiencies, including iron."
Linked to the World Declaration on Nutrition is the Plan of Action for Nutrition, which recommends that governments give priority to food-based strategies to control and prevent micronutrient deficiencies (Exhibit 1). Policy makers and planners have recognized that the short-term supplementation programmes implemented during the last two decades in many developing countries (in which populations were supplied with vitamin A capsules, iron tablets and iodine injections) have not succeeded in solving the problem of micronutrient malnutrition in a sustainable manner.
Exhibit 1. The ICN Plan of Action for Nutrition The Plan of Action for Nutrition, a document linked to the World Declaration on Nutrition, urges governments to undertake the following strategies to control and prevent specific micronutrient deficiencies: n "Formulate and implement programmes to correct micronutrient deficiencies and prevent their occurrence, promoting the dissemination of nutrition information and giving priority to breastfeeding, and other sustainable food-based approaches that encourage dietary diversification through the production and consumption of micronutrient-rich foods, including appropriate traditional foods. Processing and preservation techniques allowing the conservation of micronutrients should be promoted at the community and other levels, particularly when micronutrient-rich foods are available only on a seasonal basis." n "Ensure that sustainable food-based strategies are given first priority, particularly for populations deficient in vitamin A and iron, favoring locally available foods and taking into account local food habits. Supplementation of intakes with vitamin A, iodine and iron may be required on a short-term basis to reinforce dietary approaches in severely deficient populations, utilizing primary health care services when possible. Supplementation should be directed at the appropriate vulnerable groups, especially women of reproductive age (iodine and iron), infants and young children, the elderly and refugees and displaced persons. Supplementation should be progressively phased out as soon as micronutrient-rich food-based strategies enable adequate consumption of micronutrients." |
Although supplementation programmes have an immediate impact in individual cases, they rely on contained external support for supply of supplements, which may make them difficult to sustain in the long term. Additionally, supplementation programmes frequently fail to reach the most severe cases of micronutrient deficiency.
Food-based approaches promote the consumption of foods that are naturally rich in micronutrients or are enriched through fortification. Food-based strategies were often overlooked in the past as governments, researchers, the donor community and health-oriented international agencies sought approaches to overcoming micronutrient malnutrition that had rapid start-up times and produced quick results. Although many lives have been saved and much suffering has been avoided as a result of these efforts, many developing countries now realize that food-based strategies are the only viable, cost-effective and sustainable solution to micronutrient malnutrition (Exhibit 2). Today, many assistance agencies, non-governmental organizations (NGOs) and donor organizations provide more-comprehensive programmes to eliminate micronutrient deficiencies, including support for food-based approaches.
Exhibit 2. Reasons for Implementing Food-based Strategies Micronutrient deficiencies hinder both national economic development and the development of individual human potential. Because children are frequently the victims of this deficiencies, failure to overcome micronutrient malnutrition in a sustainable fashion jeopardizes a nation's future. Reasons for implementing food-based strategies to overcome micronutrient deficiencies include the following: . 1. Food-based strategies n are preventive, cost-effective, sustainable and income generating; n are culturally acceptable and feasible to implement; n promote self-reliance and community participation; n take into account the crucial role of breastfeeding 9 and the special needs of infants during the critical weaning period; n foster the development of environmentally sound food production systems; and : n build alliances among government, consumer groups, the food industry and other relevant organisations to achieve the shared goal of preventing micronutrient malnutrition. 2. Food, fortification, one of the food-based strategies has the potential for wide populations coverage and can involve a combination of micronutrients. 3. Nutrition education as a component of food based strategies emphasizes . 4. Adoption of food-based strategies can make possible redirection of funds previously devoted to curative health care and social welfare to other developmental activities. |
A good, varied diet is the reason most of the world's population is free from micronutrient deficiency. The elimination of these deficiencies on a sustainable basis will occur only when the diets of vulnerable groups provide all required nutrients in the proper amounts. Programmes in many countries have demonstrated that comprehensive, well-designed food-based strategies can improve diets of vulnerable groups in a relatively short time and that these improvements can be sustained. Several countries have demonstrated that micronutrient malnutrition can be overcome when government policies and programmes are directed to the goal of increasing production of and access to vitamin- and mineral-rich foods and when associated marketing and educational activities improve consumption of these foods. There are also several instances where fortification of certain staple foods provides micronutrients to large populations in a manner that is fully integrated with prevailing food production, processing and distribution patterns on a self-sustaining basis.
Investment in programmes to prevent micronutrient deficiencies is among the most cost-effective of interventions to improve health, according to the World Bank (1993). A 3-year project in the northeast region of Thailand to promote the production and consumption of vitamin A-rich foods was estimated to have a per-capita cost of US$0.42 (Smitasiri et al. 1993). Pollard (1989) estimated that the cost per mother/child unit of increasing consumption of dark green leafy vegetables in Indonesia was US$0.28.
As food-based approaches are implemented on a larger scale, their per-capita costs are likely to decrease. The Worldview International Foundation's Nutritional Blindness Prevention Programme in Bangladesh is one of the largest food-based programmes to date to have been implemented successfully. This programme to increase both production and consumption of carotene-rich foods in the district of Gaibandah (population 1.9 million) costs only US$0.13 per capita per year (1992 dollars) and had a measurable positive impact on the diet of young children within only 3 years (Greiner and Mitra 1995).
Fortification of staple foods such as flour, salt and oils is also a cost-effective approach. Lotfi et al. (1996) estimated that salt iodisation in several countries costs between US$0.02 and US$0.06 per capita per year. Fortification of sugar with vitamin A in Guatemala costs US$0.29 per capita and iron fortification of wheat flour costs an estimated US$0.02 per capita.
Micronutrient malnutrition usually occurs when diets lack variety. While short-term interventions have a role in providing specific target groups with vitamin and mineral supplements at certain times, only food-based approaches can prevent micronutrient deficiencies in a sustainable manner for most of the population. Shoppers in this market in Kathmandu, Nepal, (see picture) have access to both a variety and an abundance of food products.
Market in Kathmandu, Nepal
FAO and the International Life Sciences Institute have developed a unique manual, Preventing Micronutrient Deficiencies: A Guide to Food-based Approaches, which provides the first comprehensive description of the planning considerations required to implement food-based strategies to overcome micronutrient malnutrition. The manual's purpose is to assist policy makers, programme planners, food industry representatives and community workers to understand, implement and promote food-based strategies in their respective countries.
The solar drying of beta-carotene-rich fruits and vegetables is an effective, inexpensive low-level technology for preserving these sources of vitamin A. This Guinean woman, to ensure uniform drying, Is turning mango slices, which when dried will retain high levels of beta-carotene activity for as long as 6 months. understanding of local conditions. Community participation and the involvement of women are usually key to building support and achieving change that results in nutritional benefits.
Guinean woman turning mango slices
The manual provides technical information on the planning and implementation of food-based approaches and stresses the need to give special attention to the needs of specific vulnerable groups. It suggests a logical sequence of activities to be undertaken to implement a food-based strategy. In addition to providing useful technical information, the manual also gives resource information, including lists of technical publications and organizations that provide technical and financial support to micronutrient programmes A brief overview of the manual follows.
