Chapter 8 - Malnutrition and micronutrient deficiencies

Extent of the problem and its consequences

Protein-energy malnutrition

Assessing malnutrition and its causes

Food and nutrition interventions

Micronutrient malnutrition: mineral and vitamin deficiency disorders

Iron deficiency anaemia

Iodine deficiency disorders

Vitamin A deficiency and nutritional blindness

Preventing and combating micronutrient malnutrition through a comprehensive approach

Chapter 8 - Malnutrition and micronutrient deficiencies

Extent of the problem and its consequences

Chapter 7 provided a brief survey of the nutrient content of foods, the nutrient requirements of people at different stages of the life cycle, certain aspects of the African diet and food habits in relation to nutritional status. In the discussion of these topics, attention was drawn to some of the effects of malnutrition and micronutrient deficiencies on health and productivity. The present chapter discusses the four main forms of malnutrition and their assessment: protein-energy malnutrition (PEM), xerophthalmia resulting from vitamin A deficiency (VAD), iron deficiency anaemia, and endemic goitre and cretinism resulting from deficiency of iodine.

Tables 51 and 52 show some estimates of prevalence rates of PEM (as indicated by underweight) and micronutrient deficiencies for Africa. Such assessments are never precise, and wide variations occur among countries, but nevertheless the order of magnitude indicates the severity of the problems. It should be noted that the data reflect the situation in normal times; in some countries, severe human-caused or natural disasters have led to extensive undernutrition and even famine.

As shown in Chapter 1, Table 1, the proportion of the population chronically undernourished has risen by 5 percent (from 38 to 43 percent) in sub-Saharan Africa since the 1970s, but because of the region's annual population growth rate of approximately 3 percent, the number of people affected has doubled. Similarly, in continental Africa the total percentage of children under the age of five years who are malnourished dropped from 1975 to 1990 and has remained more or less constant at about 27 percent from 1990 to the present,¹ but owing to the rapid rise in population the actual number of malnourished children has risen dramatically from about 23 million in 1975 to 35 million in 1995 (Table 51).

¹ Current data from the World Health Organization (WHO) global database for 13 countries in sub" Saharan Africa suggest an overall increase in the prevalence of malnutrition from the early 1980s to the early 1990s (see also FAO, 1 996a).

Table 51 - Prevalence and number of underweight children under five years of age in continental Africa

Year	Percentage underweight	Number underweight (millions)
1975	30.4	22.9
1990	27.3	31.6
1995	27.0	34.8

Source: WHO, 1995b.

Table 52 - Estimated populations at risk and affected by iodine deficiency disorders, vitamin A deficiency and anaemia

Region	Iodine deficiency disordersa		Vitamin A deficiency		Iron deficiency or anaemia
	At riskb	Affected (goitre)	At riskc	Affected (clinical VAD)d
Africa	181	86	52	1.04	206
Americas	168	63	16	0.06	94
Southeast Asia	486	176	125	1.45	149
Europe	141	97	n.a.e	n.a.	27
Eastern Mediterranean	173	93	16	0.12	616
Western Pacific	423	141	42	0.13	1058
Total	1 572	656	251	2.80	2150

Sources: WHO, 1994; WHO/UNICEF, 1995.

^a There are a number of differences between these figures and previous global IDD estimates. Apart from increasingly better IDD surveillance in many countries, the differences include: use of United Nations updated population projections for 1992, use of different methodology for estimating populations at risk; and availability of prevalence data for countries for which previously no data were available.

^b Persons are considered to be at risk of IDD, although they may not necessarily suffer or manifest direct consequences, if they reside in a geographical region where the total goitre rate (TGR) in school-age children is 25%. Previous estimates of at-risk populations were based on a TGR prevalence of 210%. However, at a recent WHO/UNICEF/ICCIDD consultation it was agreed that a TGR of 5% or greater in school-age children is associated with functional impairment directly due to iodine deficiency. and therefore the 5% cut-off point has been designated for classifying populations at risk of IDD (WHO/UNICEF/ICCIDD, 1993).

^c Severe subclinical (prevalence of 220% with blood values <1).70,umol per line, with or without clinical eye signs or symptoms) and moderate subclinical (prevalence of >=10% to <20% with blood values <= 0.70 µmol per litre, with or without clinical signs or symptoms).

^d Total xerophthalmia or other clinical eye signs, i.e. Bitot's spots, corneal xerosis, keratomalacia and corneal scars, and/or symptoms, i.e night blindness.

^e n.a.: not available.

Poverty, which results in low food availability, overcrowded and unsanitary living conditions and improper child care, is a frequent cause of malnutrition. For affected individuals and households, the consequences of malnutrition are grave. In addition to the human suffering, the loss in human potential translates into social and economic costs that no country can afford. Undernutrition and micronutrient deficiencies, whether in their mildest or most severe form, may adversely affect the health and well-being of individuals. Poor nutrition and health lead to reduction in the overall quality of life and severe curtailment of development of human potential. In addition, poor health related to malnutrition reduces the resources and earning capacity of households that are already poor, thus increasing their social and economic problems.

Malnutrition and poverty often exacerbate problems of unsustainable agricultural practices as a result of the desperate efforts of the poor to obtain adequate food. There is also evidence that poor nutrition has a significant impact on reproduction, physical activity, child growth and development, learning capacity and work performance. In addition, malnutrition lessens an individual's ability to fight infectious disease, thus compounding the extent and severity of illness among the poorly nourished.

Protein-energy malnutrition

PEM results when the body's needs for energy and protein or both cannot be satisfied by the diet. It has a wide spectrum of manifestations, and its severity ranges from weight loss to growth retardation to distinct clinical syndromes, frequently associated with deficiencies of vitamins and minerals (e.g. vitamin A, iron and zinc). The most severe clinical manifestations of PEM are kwashiorkor and marasmus.

Symptoms of marasmus include:

· apathy;

· growth failure, with weight below 60 percent of expected weight for age;

· wasted muscles (muscles that are visibly thinner and less developed than normal) and very little fat under the skin;

· diarrhoea.

Marasmus is commonly seen in babies whose mothers had inadequate breastmilk and occurs most clearly during the child's first year. It may also occur when there is too long a reliance on breastmilk without complementary solid foods. Improper use of bottle-feeding is closely associated with marasmus, especially in urban areas.

Symptoms of kwashiorkor include:

· fine, reddish-brown, lustreless hair with loose curls;

· apathy;

· growth failure, with weight usually below 60 percent of expected weight for age, but this depends on the degree of oedema;

· oedema (excess fluid under the skin, causing puffiness);

· blotchy skin;

· prominent stomach;

· diarrhoea;

· wasted muscles.

Kwashiorkor usually occurs later than marasmus and is uncommon under one year of age. It occurs most frequently when children are taken off a diet of breastmilk and have to rely only on the starchy staple. On the same kind of diet and in the same household, one child may develop marasmus and another kwashiorkor. The causes of kwashiorkor are still not fully known; however, it has often been found to occur in association with diarrhoeal infections, which indicates that the causes go beyond nutritional factors.

Infants and young children are the most severely affected by PEM because of their high energy and protein needs relative to body weight and their particular vulnerability to infection. Children's health is most in danger from about three months of age until they can feed themselves, perhaps at about three years of age. During this period several weaning practices can have an adverse effect on child nutrition. One factor is the age at which food supplements are introduced into the child's diet; others include the method of food preparation, the frequency of feeding and the energy density of weaning foods. In all circumstances, but especially during illness, young children need to be fed frequently during the day. Mothers may have difficulty in feeding children often enough if they are working in the fields; thus the limited time available to mothers may be an important constraint on children's food intake.

Assessing malnutrition and its causes

Food and nutrition assessment is necessary for the identification of the poorest and most vulnerable people in a community and the selection of appropriate interventions aimed at preventing malnutrition and improving people's access to food. Food and nutrition situations may be assessed by various methods and indicators. Quantitative methods range from assessment of the availability of, access to and consumption of food to surveys of indicators of nutritional status such as body measurements, mortality rates and clinical and biochemical signs. These quantitative methods are often complemented by collection of qualitative information, which is useful in the interpretation of statistical results and for gaining a better understanding of the causes of malnutrition.

Indicators for PEM include children's body weight and height, infectious disease rates, food intake relative to need and body mass index (BMI) for adults.

Chronic dietary energy deficiency

Assessment of the extent of chronic dietary energy deficiency at the national level is usually based on an estimate of dietary energy supplies (DES) calculated from food balance sheets combined with information about the distribution of food supplies. However, the use of food balance sheet data to assess nutrition situations is problematic, as it does not provide a direct assessment of food consumption (see Box 58). Given the limitations of using aggregate supply figures to assess nutritional well-being, FAO has developed a methodology that estimates the number and percentage of people who over a period of one year do not have access to enough food to meet their energy needs. This proportion of the population may be referred to as the "chronically undernourished". However, since these figures do not take into account those persons facing problems of intrahousehold food distribution, seasonal or acute malnutrition or infections, the actual number of undernourished people is likely to be higher. The methodology is based on estimates of the distribution of available food supplies among households and the application of a cut-off point relating to energy requirements.

Anthropometry

The most accurate and rapid way of assessing the nutritional and health status of a population, a community or an individual is by means of anthropometry. Anthropometric measurements are measurements of the body (weight and height), often in association with age, which permit the development of certain indexes reflecting individual or population characteristics. "Wasted" (thin), "stunted" (short) and "obese" are terms that describe the nutritional status of individuals, and they are quantitatively expressed in various anthropometric indexes as discussed in Box 59, which summarizes the use of anthropometry as a method of assessing nutritional status. In children, body weight and height are among the most important indicators of PEM.

In adults, most anthropometric studies using weight for height have centred on health clinic patients, particularly pregnant women. Use of the body mass index (BMI), as defined in Box 59, has generally been limited to studies of adult obesity. A review of available data on BMI from various regions (FAO, 1994e) suggests that an adult's BMI is closely related to health status and may also provide an index of functional disability. Decreasing BMI (less than 18.5) is linked to increasing illness and consequent reduced work capacity (see Figure 31). As BMI falls, community-related productive work and strenuous activity may be reduced to reserve energy for vital agricultural and other domestic activities. At the same time, leisure pursuits and interests within the family may also be sacrificed, including adult interaction and stimulus for young children. In assessing the overall food adequacy within a community it would be useful to combine a measure of adult BMI with assessments of children's nutritional status, in order to select the most effective and appropriate interventions.

Box 58 - Using food balance sheet data to assess nutrition situations Precise assessments of national nutritional levels are difficult to make. National surveys of nutritional status and actual levels of food consumption are perhaps the most accurate sources of information, but they are costly, time-consuming and often impractical, especially for low-income countries. An alternative and frequently more feasible approach is that based on FAO's food balance sheets, which examine each nation's food situation. Food balance sheets provide information about a country's average per caput dietary energy supply (DES), which indicates the amount of food available for human consumption in the country, among other data. DES is an imperfect tool and it may be misleading since it does not provide a direct assessment of food consumption. For instance, people may be too poor to buy the food that is available. Attempts to assess food adequacy by comparing DES with requirement figures sometimes fail for these reasons. Furthermore, the answer to the question of which requirement figures to use is not always obvious. Should the requirement figure be that for mere survival, or should it refer to a particular level of activity? Despite such limitations, when DES is combined with information about the distribution of food supplies, it is possible to estimate the number of people whose energy intake is too low. DES also correlates closely with other indicators of health and socio-economic development. Recently, in connection with the FAO World Food Surveys, there have been refinements in the concepts used to estimate the number of people in developing countries who do not have access to enough food to meet their energy needs on average during a year. While this group is actually classified as chronically dietary-energy deficient, this is commonly taken to reflect the proportion of the population chronically undernourished. The modifications incorporate concerns of inequitable distribution and variations among households in relation to estimates of energy needs. Additional conceptual modifications to the methodology have occurred since the Fifth World Food Survey in 1986. These include modifications to the previous cut-off points (1.2 and 1.4 BMR) used to define energy needs. Basal metabolic rate (BMR) refers to the energy expenditure of an individual while in the fasting state and lying at complete rest. A higher, more realistic energy level (1.54 BMR) has now been adopted which represents energy required to maintain body weight and to support light activity. Increasing the energy requirement level used consequently increased the estimated absolute number of persons affected by dietary energy deficiency.

Source: FAO/WHO. 1992g.

Box 59 - Anthropometry as an indicator of nutritional status Anthropometric indexes provide an approximate reflection of nutritional status. The indicators used most often are the body's weight and height, in relation to a subject's age and sex. Others include arm, head and thigh circumferences and skinfold thicknesses. The main anthropometric indexes used are: weight for height, height for age, weight for age and body mass index (BMI). BMI = W/H2, that is, weight in kilograms divided by the square of height in metres. WHO uses United States National Center for Health Statistics (NCHS) data as a standard since many studies have shown that the growth of normal, healthy and adequately nourished children almost always approximates these reference values. Preferably, anthropometric data for children are quoted in terms of "Z-scores" based on standard deviations (SDs) above or below the median reference value for a person of a given age. The level of median minus 2 SD is usually taken as the cut-off point or threshold, below which the status is considered unsatisfactory. that is, undernutrition exists. Weight for height This index is used for both adults and children in relation to accepted reference values. In acutely undernourished people (those who have had inadequate dietary intakes or an acute infection within recent weeks), decline in body weight is relatively rapid; height remains unchanged in adults and changes very slowly in children. Weight for height is a measure of "acute undernutrition" or "wasting" and is the index most used in nutritional emergencies as well as in long-term situations of undernutrition, such as famine. Weight for height is useful in assessing nutritional status of children and adults. In children, weight for height ratios can be used without knowing the individual's age. In most circumstances less than 2 percent of children under five years of age are below the median minus 2 SD. If 5 to 10 percent of the population group is below this level, the degree of acute undernutrition may be described as moderate; if the proportion is beyond 10 percent, this is generally considered to be a severe situation. Height for age This parameter is used for assessing "chronic undernutrition" in children. Prolonged undernutrition causes retardation of growth in both height and weight, to a roughly comparable degree. Impaired gain in height is called "stunting". Gain in height is most affected by long-standing environmental and socio-economic factors, hence it reflects general socio-economic conditions. In developing countries, widespread chronic undernutrition is common and the proportion of individuals below the median minus 2 SD is often in the range of 20 to 60 percent, with an average near 40 percent. Populations in which 25 to 50 percent of the children under five years of age have height for age below the median minus 2 SD are commonly considered to be moderately affected, while those with more than 50 percent below the cut-off are considered to be severely affected. Weight for age The proportion of children under five years of age who are below the median minus 2 SD (weight for height) ranges from 10 to 50 percent with an average around 20 to 30 percent in many developing countries. Populations with 20 to 40 percent of children who are underweight for age can be considered moderately affected, and those with more than 40 percent are severely affected. The weight for age indicator is available more often than weight for height or height for age but is more difficult to interpret because it can be affected by either acute or chronic undernutrition. Serial weighings indicate incremental changes in weight, giving a more dynamic picture of growth velocity and the nutrition situation. This is, in fact, a much better way of assessing nutrition although it is more difficult to carry out. Body mass index (BMI) This index, defined as W/H2, provides a measure of body mass, ranging from thinness to obesity. Empirically, it has been found that the normal range of BMI is from 18.5 to 25.0. Individuals with a BMI above 30 are considered obese, and those with a BMI below 18.5 are considered underweight. Some studies have shown increased mortality rates in both underweight and overweight subjects.

Source: WHO Working Group, 1986.

FIGURE 31 - Body mass index and "equivalent days" of illness among Rwandese women, 1982

Source: FAO, 1994e.

Infant and child mortality

Among infants and young children, poor nutritional status and infection, as well as other environmental and socio-economic factors, can lead to death The infant mortality rate (IMR) is strongly influenced by nutritional factors such as foetal undernutrition stemming from maternal undernutrition, infections and/or anaemia during pregnancy. Specific mortality data for infants are often difficult to obtain because population information for infants is unknown and deaths may not be reported in many countries.

In countries where the prevalence of infectious and parasitic diseases is high, about one-half of all deaths occur before five years of age, and one-third of these deaths occur after the first year of life. The under-five mortality rate (U5MR) for the least-developed countries is about 200 per 1000 live births. In sub-Saharan Africa, the IMR fell from 152 to 109 per 1000 live births between 1960 and 1993 (UNICEF, 1995).

Low birth weight

Low birth weight (LBW), a major health problem in most African countries, is associated with neonatal (age 0 to 28 days) and post-neonatal (age 29 days to one year) mortality. A baby who weighs less than 2.5 kg at birth is considered to be of low birth weight. LBW is associated with prematurity (i.e. gestational age below 37 weeks) and intra-uterine growth retardation. The causes of LBW are multiple and interrelated. Important factors are the mother's low intake of food energy or low weight gain during pregnancy, low pre-pregnancy weight, short stature and diseases such as malaria. Continual cycles of pregnancy and lactation, combined with the seasonal stress of heavy agricultural work, place strain on the nutritional status of women and reduce their capacity for caring activities within the family.

In a study in the Gambia, feeding a high-energy supplement to underweight pregnant women markedly reduced the incidence of LBW babies, from 28.2 to 4.7 percent (see Box 60 and Table 53). However, in controlled clinical trials on the effects of energy and protein intakes on pregnancy outcome, balanced protein and energy supplementation was demonstrated to result in only modest increases in maternal weight gain and foetal growth, even in undernourished women, and did not confer long-lasting benefits in terms of infant and child growth and health performance (Kramer, 1993). Increasing evidence suggests that pre-conception nutritional status is closely related to pregnancy outcome. Although more work on the effects of maternal supplementation on birth weight is necessary, these studies suggest that a shift of focus may be required from maternal health care to providing better nutrition and health services for women in general, especially for teenage girls and young women. An increased emphasis on young women's well-being would be a cost-effective intervention for improvement of the health and nutritional security of the whole household.

Box 60 - Prenatal supplementary feeding of African women and birth weight Providing supplementary food to pregnant women may be an efficient and cost-effective form of nutritional intervention aimed at improving child growth and survival prospects in chronically undernourished populations. However, the maximum achievable benefit of prenatal supplementation has not yet been defined. We report here the effects on birth weight of a groundnut-based biscuit supplement given to pregnant Gambian women which resulted in a substantially higher net energy increment than did any previous supplementation studies. A threshold effect was apparent in which the supplement was only effective when women would otherwise have been in negative energy balance. The pre-supplement dietary energy intake of pregnant women in Keneba varied from an average level of only 1 480 kcal per day in the dry season to a minimum of 1 300 kcal per day in the wet season. Despite this the women were in positive energy balance in the dry season (February to June) as judged by satisfactory weight gain and deposition of subcutaneous fat. In the wet season (July to January) women were in marked negative energy balance due to the combined stresses of a reduction in energy intake and a high energy expenditure on agricultural tasks. Maternal protein intakes were not grossly deficient before supplementation and were slightly in excess of recommended intakes after supplementation. Methods The supplement consisted of groundnut-based biscuits and a vitamin-fortified tea drink. The supplement was offered six days each week, and consumption was carefully supervised and measured in a purpose-built supplementation centre. Birth weights, to the nearest 10 g, were usually recorded immediately after birth, and always within 24 hours. Summary of results Gambian women, who show marked seasonal fluctuations in energy balance, were offered a dietary supplement during pregnancy. This resulted in a net energy increment of 431 kcal per day. In the wet season, when the women were normally in marked negative energy balance due to food shortages and a high agricultural work load, the supplementation improved birth weight by a mean of 224 9 and reduced the incidence of low-birth-weight babies (<2.5 kg) from 28.2 to 4.7 percent [see Table 53]. In the dry season, when the women were previously in positive energy balance despite an energy intake of only 60 percent of the recommended dietary allowance, the supplement had no beneficial effect on birth outcome. This threshold effect indicates the need to identify truly at-risk groups for prenatal supplementation programmes in developing countries.

Source: Prentice et al., 1983.

Table 53 - Effect of prenatal dietary supplementation on birth weight distribution, the Gambia (% of total births)

Birth weight (g)	Dry season	Wet season	Combined
Pre-supplementation
>3 500	5.4	2.2	3.8
3 001-3 500	40.4	25.8	33.3
2 501-3 000	42.5	43.8	43.2
<2500	11.7	28.2	19.7
Post-supplementation
>3 500	8.0	11.6	9.7
3 001-3 500	42.0	37.2	39.8
2 501-3 000	42.0	46.5	44.1
<2 500	8.0	4.7	6.4
t test	NSa	P<0.01	P<0.01

Source: Prentice et al.. 1983.

^a Not significant.

Qualitative assessment of food and nutrition situations

Anthropometric indexes, mortality rates and low birth weight are quantitative indicators which describe the nutritional and health status of individuals and population groups but do not provide an explanation of the underlying causes of the problems. To provide a better understanding of the causes of malnutrition and the most effective ways of combating them, information is needed about many aspects of life within and around the community. It will often be necessary to collect information that is qualitative and that reflects people's opinions and perceptions of malnutrition and its causes.

Rapid rural appraisal is one of a number of approaches to collecting mainly qualitative information. It is based on a number of techniques including secondary data review, direct observation, semi-structured interviews, workshops, analytical games, diagrams and maps. Field workers use checklists of information needs to structure guided yet informal discussions with rural people (see Box 61). A related method is participatory rural appraisal, which is a type of rapid rural appraisal in which the emphasis is shifted towards greater participation and involvement of the local community. It involves people in assessing and analysing their own food and nutrition situation and in prioritizing and selecting actions and projects which the community can implement independently or with partial external assistance. Participatory rural appraisal envisages a dialogue of equals, with the advisory team and the rural people sharing experiences and learning from one another. It is usually the beginning of a longer-term development process in which the community members are active participants from the start to the end of a project, i.e. from problem assessment and analysis, to prioritization and selection of activities and projects, to implementation and finally to monitoring and evaluation of progress towards stated goals.

Food and nutrition interventions

As discussed in earlier chapters, the underlying causes of chronic malnutrition are multifaceted, and to improve nutrition sustainably simultaneous action may be required in many areas. In many cases poverty and restricted access to food are the underlying causes of malnutrition. The pursuit of household food security must start, therefore, in making food more accessible to the poor. This can be achieved by increasing food production and availability, incomes and ownership of assets or by providing a safety-net of social security for the needy.

Promotion of small-scale community-based agriculture and food processing is central to improving household food security among the rural poor. It offers increased food, employment and income. In general, increases in real income translate into higher food consumption and improved nutrition. Gains from a combination of cash crops and livestock can also reach into the community, providing opportunities for off-farm employment. Making credit available to the poor, particularly women and others lacking any form of collateral, can result in new sources of income and improve household food security. Women tend to spend a significant part of any additional income on food and other necessities for the family.

Box 61 - Participatory appraisal of community food and nutrition problems The following checklist includes a number of questions that might be explored to find out more about the causes of food and nutrition problems in a community. It is meant to stimulate a dialogue about similarities and differences among households and/or social groups. The checklist is not complete but provides examples of the types of issues that might be included. Local food system and recent changes · How do households obtain their food? · What do they produce? What do they purchase? Other sources? · Has the situation changed in the last years? How? Why? · How are these changes perceived? Production for household consumption · Which foods are produced by the household? · How many months do staples last? · What are the months of food scarcity? · What coping mechanisms or activities do households employ to get food in months of scarcity? Food habits, preferences and related beliefs · How many meals do the different household members eat per day? Are there seasonal differences? · What do they eat? Any snacks in between? · Do children eat differently? How? Which age groups (infants, school-age children)? · How do eating patterns change as a coping mechanism in times of scarcity? How is food obtained in such situations? · If the household had more resources, what foods would its members like to eat more of, or more often? · Which foods are considered especially good or to be avoided? When? By whom? Food preparation and usage · How is food prepared at household level? Where? On what kind of stove? How often per day? · Are any special foods prepared for small children? What types of food? · How is food portioned out within households? Who eats first? Nutritional status · Is malnutrition a familiar notion to the community? · What does the community perceive as malnutrition? · How important is it? · How many thin children or adults are there in the community? · How do people describe or explain this? What do they do about it? Social aspects · Which are the poorest households within the community? Why? · Do they suffer from food scarcity? Do they have malnourished children?

Source: Adapted from FAO, 1993f.

Agricultural projects and small-scale, labour-intensive food processing industries often offer the greatest opportunity for socioeconomic development and consequently for sustained improvement in the nutritional status and food security of the poor. Because of past failure to include nutrition objectives in agricultural development policies and programmes, opportunities to combine efforts to enhance household food security and to improve human welfare through sustainable development have generally been missed. Sustained improvements in nutritional well-being can best be achieved by accelerating agricultural production; expanding food supplies; integrating nutrition considerations into agricultural development policies and programmes and larger-scale investment projects; implementing targeted nutrition interventions; and empowering local communities to address their own food and nutrition problems.

If in the nutritional assessment of a community the anthropometric evidence indicates that adult BMIs are adequate but children's growth is poor, attention should also be directed towards nutrition education, reducing infection and promoting parental care, rather than just enhancing agricultural productivity and economic conditions. Appraisal of intrafamilial food distribution might also be indicated.

If morbidity and mortality in the under-five population is identified as a major problem, attention could be directed to the promotion of breastfeeding and improved weaning practices. If low birth weights are the major evidence of malnutrition, care must be given to the improved health and nutrition of women, including assessment and treatment of iron deficiency anaemia. However, it is not possible to prescribe specific interventions to prevent chronic undernutrition; interventions must be case specific, and they must be assessed, analysed and selected through constant dialogue and communication with the affected communities.

Micronutrient malnutrition: mineral and vitamin deficiency disorders

Micronutrient malnutrition is the term now commonly used to refer to the three main vitamin or mineral deficiencies of public health significance: iron deficiency anaemia, iodine deficiency disorders (IDD) and vitamin A deficiency. Micronutrient deficiencies substantially affect the nutritional status, health and development of a significant percentage of the population in many countries, both developed and developing. These deficiencies contribute to growth retardation, morbidity, mortality, brain damage and reduced cognitive and working capacities among both children and adults.

Iron deficiency anaemia

In Chapter 7 some biochemical aspects of iron in human metabolism were discussed in relation to the availability and assimilation of haem and non-haem iron from the diet. Attention was drawn to the important effects of interacting components in the diet, especially vitamin C, in increasing the availability of non-haem iron. The particular needs of women and children were identified, as well as the effects of parasites and infection on the iron status of the body.

Iron deficiency anaemia decreases individual potential and has adverse effects on learning, productivity and earnings. Anaemia leads to reduced physical activity and decreased work performance because of the reduced transportation of oxygen from lungs to tissues and of carbon dioxide in the reverse direction. Iron deficiency may also result in muscle dysfunction.

A normally nourished individual placed on a diet that is deficient in iron undergoes first a loss or depletion of body stores. There is increasing evidence that stored iron may have a role in human susceptibility to, and morbidity from, infections.

Anaemia, together with malnutrition, is among the major causes of childhood morbidity and mortality in many developing countries. When anaemia occurs in infancy or childhood it is associated with significant loss of cognitive abilities as well as decreased physical activity and reduced resistance to disease. Providing iron supplements to schoolchildren with iron deficiency results in improvement in selective learning and school achievement tests. Iron supplementation can also improve appetite in undernourished children and thus speed up their rate of recovery from malnutrition and their subsequent physical growth.

Iron deficiency in women of child-bearing age increases the hazards associated with complications of pregnancy, premature birth and low birth weight and causes infants to enter life with sub-optimal iron reserves. Frequent pregnancies often compound this problem and result in further deterioration in the health and nutrition status of the mother and her subsequent children.

Assessment of the prevalence and causes of anaemia

The assessment of the prevalence of anaemia in a community is often based on surveys of women and children, as these are the groups most at risk. Figure 32 shows the prevalence of anaemia in pregnant women, assessed on a global basis. It is estimated that 60 percent of pregnant women and 45 percent of non-pregnant women in developing countries are anaemic (Figure 33).

The symptoms of anaemia vary significantly and can be caused by conditions other than iron deficiency. The most practical form of assessment is therefore based on the determination of the blood haemoglobin level. Table 54 shows the haemoglobin levels generally accepted to indicate anaemia in different members of the family. Haemoglobin levels rarely exceed 16 g per 100 ml. Blood tests are normally taken at health clinics and are carried out routinely for pregnant women. Children may be tested at school during special surveys or as an initial action before the definition of a treatment and control programme for a number of nutritional disorders.

FIGURE 32 - Prevalence of anaemia in pregnant women, 1988

Source: WHO, 1992 (quoted in UN ACC/SCN, 1992).

FIGURE 33 - Proportion of people in developing countries who are anaemic

Source: DeMaeyer et al., 1989.

Analysis of the causes of anaemia may involve dietary surveys to establish the level and type of iron intake from the diet, together with analysis of the health situation to determine the causes of loss of iron or of poor assimilation from the diet. The analysis may also include a study of the social and environmental situation, including the educational and income levels of the population and the local sanitation conditions such as availability of clean water and use of latrine facilities.

Table 54 - Haemoglobin levels in anaemia

Group	Haemoglobin levela (g/100 ml)
Children 6 months 10 5 years	11
Children 610 14 years	12
Men	1 3
Women (not pregnant)	12
Women (pregnant)	11

Source: UN ACC/SCN, 1991.

^a Haemoglobin below these levels means anaemia Mild: below the values given but more than 10 Moderate: 7 to 10. Severe: below 7.

On the basis of this analysis, and within the constraints of the programme's financial resources, a number of actions may be proposed. Whenever possible, the target community should be involved at all stages of the assessment and analysis of the community's nutritional situation. The final choice of priorities in the actions to be taken should also rest with the community, under guidance from the programme staff and from local organizations.

Selecting interventions for control and prevention of iron deficiency anaemia

One of the primary strategies available for intervention is nutrition and health education to improve dietary intake of foods rich in iron, folate and vitamin C and to reduce the consumption of interfering substances. In a nutrition education programme, topics that should be covered in relation to the prevention of iron deficiency anaemia in young children include support for breastfeeding and home preparation of suitable weaning foods. Other supporting interventions include supplementation, which is the provision of medicinal iron to the individual, and fortification, which is the addition of the micronutrient, in this case iron, to a suitable food (see Box 62). In areas where parasitic diseases and malaria are major contributors to anaemia, their control will form an important part of the overall strategy. Where hookworm infections are prevalent, regular, periodic deworming will help reduce iron losses.

Depending on the extent of the problem, a medical supplementation programme may be appropriate. However, large-scale supplementation requires an adequate support and delivery programme, which is often expensive. A supplementation programme may be possible for a limited period under project financing, but for sustainability it must be incorporated into an effective community health care system. Otherwise, it risks collapse when project funds are withdrawn. A further challenge involves ensuring that the medication is taken for the four to five months of treatment that are often prescribed.

Improving dietary intake is a more long-term approach and is the preferred and more sustainable strategy. The production and consumption of food plants rich in iron and folic acid, particularly green leafy vegetables, together with fruits rich in vitamin C to enhance iron absorption, should be promoted. Production and consumption of animal and dairy products should also be encouraged whenever possible. Poor diets result more often from poverty than from ignorance, however, and the ultimate solution lies in economic and social measures that can ensure a more equitable distribution of resources, including food.

Box 62 - Considerations in the selection of an intervention programme for the control of iron deficiency anaemia · Supplements. Usually medicinal supplements to at-risk groups such as pregnant and lactating women, children or occasionally labourers. · Fortification with iron, or ascorbic acid, or both. A suitable food and a suitable nutrient preparation must be found. · Nutritional and health education. More difficult with iron than with some other nutrients. · Parasite control. Treatment of those infected with hookworms, with Schistosoma haematobium, S. mansoni or S. japonicum, or with other parasites; plus improved sanitation, water supplies and knowledge of transmission of infection. · Socio-economic measures. Interventions to improve economic status and levels of living.

Source: WHO, 1977.

In the medium-term perspective, the most cost-effective intervention for the alleviation of iron deficiency anaemia in urban and rural areas is food fortification. This strategy requires identification of a suitable food, which should already be in use by the majority of the target groups on a regular basis. For example, iron-fortified salt has been used in India. A major advantage is that no special distribution system is necessary, as distribution is provided through the existing food markets for the selected commodity.

Box 63 provides a brief review of the national programme for the control of nutritional anaemia in the United Republic of Tanzania.

Iodine deficiency disorders

The nature and causes of IDD, including endemic goitre and cretinism, have been examined from a dietary viewpoint in Chapter 7. The cause of these disorders, and potential methods for their control and elimination, have been known for many decades. Nonetheless goitre, often accompanied by crippling endemic cretinism in the community, still affects millions of people throughout the world. The characteristics of hypothyroidism are described in Chapter 7.

The immediate cause of IDD is a deficiency of iodine in the diet. The underlying cause is a deficiency of iodine in the local soil on which vegetation grows, animals graze and crops are cultivated, which results in a shortage of iodine in local foodstuffs. The effects of iodine deficiency are most seriously manifest during pregnancy and parturition. Iodine deficiency disorders also have economic and social consequences for development (see Box 64).

The severity of IDD is classified on the basis of the prevalence of goitre and the mean level of urinary iodine in the test population.

Box 63 - Causes and control of nutritional anaemia in the United Republic of Tanzania The cause of iron deficiency anaemia in Tanzania has been found to be a combination of low dietary intake; low big-availability due to the plant origin of the iron; poor absorption due to the presence of inhibitors such as phytates, tannins and caffeine; and increased losses due to the presence of blood-depleting parasites like hookworm. Folic acid deficiency is mainly due to the increased requirements during pregnancy which are not balanced by adequate dietary intake, and the high prevalence of malaria. The programme for the prevention and control of nutritional anaemia in Tanzania has a national coverage but is targeted mainly to pregnant women and children under five years of age. The programme aims at addressing the major causes of anaemia in a fashion which ensures sustainability. The dietary approach aims at iron and folic acid deficiency anaemia (IFADA) and consists of the promotion of the production and consumption of iron and folic acid rich foods, particularly green leafy vegetables and vitamin C rich foods like fruits which enhance iron absorption. Animal and dairy products are also encouraged whenever possible. A pharmaceutical approach through the supplementation of iron folate tablets targeted to the most vulnerable group, pregnant women, through the Essential Drug Programme (EDP) and the Maternal and Child Health (MCH) system has also been implemented for a number of years. General public health measures aimed at the strengthening of control measures against malaria, schistosomiasis and intestinal parasites like hookworm form an important component of the programme. The integration of these measures with the vitamin A programme and in particular with other existing health and nutrition programmes, coupled with adequate research, information, communication and education and management information systems, ensures community participation and programme sustainability.

Source: Kavishe, 1991.

In many areas of the world, particularly in Africa, iodine deficiency occurs but has not yet been fully recognized. According to recently revised estimates of the Micronutrient Deficiency Information System (MDIS), about 1 572 million people globally are at risk of iodine deficiency: 486 million in Southeast Asia, 423 million in the Western Pacific, 168 million in the Americas, 181 million in continental Africa, 141 million in Europe and 173 million in the Eastern Mediterranean (WHO/UNICEF/ICCIDD, 1993). In Africa alone, 86 million people (13.1 percent of the total population) are estimated to have goitre. Figure 34 indicates the estimated national status of IDD prevalence for countries in continental Africa.

Box 64 - Why combating iodine deficiency disorders is important Iodine deficiency delays social and economic development in the area because: · There are more handicapped people who need care from the community. · Cattle, goats, chickens and other domestic animals are also iodine deficient. They grow more slowly and reproduce less. · Local people are mentally slower and less energetic than healthy people. It is more difficult to motivate them. · Iodine-deficient children are difficult to educate and are less likely to get good jobs when they grow up. · Children with cretinism often die young. Severely disabled children who survive can be a burden on their families and communities. Less disabled people, if they are physically strong, may be able to do simple manual tasks. · A large goitre may reduce a person's chances of marriage or employment.

Source: King and Burgess, 1993.

In Tanzania, an estimated 6.25 million people (25 percent of the total population) are affected by IDD (Kavishe, 1987). Pregnant and lactating women have the highest incidence of IDD, 52 percent, and children under five years of age have the lowest incidence, l 3 percent. In an Ethiopian study, the overall prevalence of goitre in seven provinces of Shoa Region was found to be 32.7 percent, while the incidence in the female population of Merhabete Province was as high as 60 percent (see Table 55).

Interventions for control of IDD

The treatment and prevention of IDD depend on increasing the intake of iodine in the affected population, either by medicinal supplementation or by fortification of a component of the diet. Iodization of salt has greatly reduced the prevalence of goitre in Argentina, Colombia, Mexico and Guatemala, but this approach may not always be easy to implement. Tanzania chose to use a targeted distribution of iodinated oil capsules as a short-term measure. The results and costs of that programme are given in Box 65. Table 45 in Chapter 7 shows the daily needs for iodine.

FIGURE 34 - Prevalence of iodine deficiency disorders in Africa: total goitre rate (TGR) in school-age children

Source: WHO/UNICEF/ICCIDD, 1993.

Table 55 - Prevalence of goitre, xerophthalmia (Bitot's spots) and anaemia in seven provinces of Shoa Region, Ethiopia

Province/gender group	Number examined	Goitre		Xerophthalmia		Anaemia
		(No.)	(%)a	(No.)	(%)	(No.)	(%)
Chebona-Gurage
Men	3 705	928	25.0	14	0.4*	960	25.9
Women	1 457	582	39.9*	1	0.1	288	19.8
Both sexesb	5 162	1 510	29.3	15	0.3	1 248	24.2
Merhabete
Men	704	276	39.2	15	2.1	226	32.1
Women	629	379	60.3*	9	1.4	183	29.1
Both sexes	1 333	655	49.1	24	1.8	409	30.7
Selale
Men	493	61	12.4	16	3.2	153	31.0
Women	374	81	21.7	4	1.1	86	23.0
Both sexes	867	142	16.4	20	2.3	239	27.6
Kembatana-Hadya
Men	1 063	296	27.8	4	0.4	275	25.9
Women	773	395	51.1*	2	0.3	168	21.7
Both sexes	1 836	691	37.6	6	0.3	443	24.1
Tegultna-Bulga
Men	698	116	16.6	5	0.7	2	0.3
Women	676	195	28.8*	3	0.4	6	0.9
Both sexes	1 374	311	22.6	8	0.6	8	0.6
Yifatna-Timuga
Men	1 878	533	28.3	44	2.3	217	11.6
Women	1 885	799	42.4*	1 6	0.8	165	8.8
Both sexes	3 763	1 332	35.4	60	1.6	382	10.2
Menzena-Gishe
Men	238	87	36.6	0	0.0	5	2.1
Women	167	87	52.1	1	0.6	6	3.6
Both sexes	405	174	43.0	1	0.2	11	2.7
Total
Men	8 779	2 297	26.2	98	1.1*	1 838	20.9*
Women	5 961	2 518	42.2*	36	0.6	902	15.1
Both sexes	14 740	4 815	32.7	134	0.9	2 740	18.6

Source: Wolde-Gebriel et al., 1992.

^a *: Prevalence was significantly higher than in the opposite sex, P < 0.001.

^b The prevalence values for the sexes combined expressed as a percentage have not been corrected for the unequal number of males and females in the sample studied.

In remote areas, a long-term intervention in the form of injection of iodized oil may be justified. The advantage of the treatment is its prolonged effect, lasting for three or more years, but there are also associated problems such as high cost and the risk of transmission of needle-borne infections.

Vitamin A deficiency and nutritional blindness

On a global basis, it has been estimated that at least 251 million children of preschool age are at risk of VAD, as shown biochemically, and 2.8 million are clinically affected (WHO/ UNICEF, 1995). In Africa 52 million children are at risk of VAD, and an estimated 1.04 million of these have clinical signs of the deficiency. Figure 35 shows the geographical distribution of vitamin A deficiency in Africa in 1995.

Every year, 250 000 to 500 000 children become partially or totally blind from VAD, and two-thirds of these children die within a few months of going blind. Apart from these victims, many more children - ten to 20 times more - are at risk in terms of health and survival because VAD impairs resistance to infection.

Causes of vitamin A deficiency and nutritional blindness

Xerophthalmia comprises a range of disorders in which the mucous membranes of the eye become abnormally dry. It is caused most immediately by a deficiency of vitamin A in the diet, and if it is not promptly treated it can lead to blindness. More than 50 percent of children who develop xerophthalmia become very ill with other infections because lack of vitamin A reduces their natural resistance, and many die. See Box 66 for the clinical signs used in the assessment of the prevalence of xerophthalmia.

Box 65 - The use of iodinated oil capsules in the United Republic of Tanzania Tanzania chose to use iodinated oil in areas of severe IDD because a salt iodation programme had taken a long time to implement. The objective was to eliminate severe IDD areas by 1993. The advantage with the oral preparation is that it can be delivered by even non-medical personnel and avoids the use of needles which have a potential and real risk in spreading diseases such as acquired immunodeficiency syndrome (AIDS) and hepatitis B. The target group for the iodinated oil capsule distribution is everybody aged one to 45 years in districts severely affected by IDD. The younger age group, below one year, was excluded in the hope that since there is nearly universal breastfeeding for children under one year of age, they will get their iodine from breastmilk. For the older age group, above 45 years, the requirements for iodine are low, and members of this group are more prone than the younger age groups to the effects of excessive iodine which the programme wanted to avoid. The dose given is 380 mg of iodine (two capsules) for the target population once every two years. The criteria for choosing the severely affected districts was initially based on a visible goitre rate (VGR) of 10 percent or more, but owing to political and public pressure this was lowered to a prevalence of combined grade 1 b and VGR of 10 percent or more. According to these criteria 30 districts were categorized as having severe IDD. On average, the 30 districts have VGR of 11 percent, VGR+1 b of 31.3 percent and total goitre rate (TGR) of 57.1 percent. The population involved is about 5 million. The iodinated oil capsules are distributed through the primary health care (PHC) system or in a campaign using the primary schools and the government and Chama Cha Mapinduzi (CCM) Party infrastructure for mobilization and compliance. The iodinated oil capsule supplementation programme has been shown to have had a positive impact on the problem of IDD. For example, in three primary schools in Mahenge, Ulanga District, Morogoro Region, the VGR dropped by 71.7 percent and the TGR by 30.7 percent. Specific studies have also shown a normalization of urinary iodine excretion and thyroid hormone levels in those given the capsule within 56 days. An estimate of the costs involved showed that they are modest. If all costs including the capsule, distribution, training, operational research, monitoring and evaluation, advocacy and personnel are considered, the cost amounts to about US$0.40 per case of IDD prevented or per person treated for severe IDD. The value of one iodinated oil capsule in Dar-es-Salaam is equivalent to about US$0.10, which adds up to US$0.20 per dose. The estimated direct cost for distribution is less than US$0.01 per capsule. If all the other overhead costs are added, the cost per dose works out at about US$0.30. By any standards, this cost is a modest one for preventing the birth of cretins and for increasing the educability and productivity of a population.

Source: Adapted from Kavishe, 1991.

FIGURE 35 - Prevalence of vitamin A deficiency in Africa, April 1995

Source: WHO/UNICEF. 1995.

Notes: The designations do not necessarily imply that VAD seventy is uniformly distributed throughout each country. See Table 52 for definition of levels of severity.

Box 66 - Signs of xerophthalmia The signs of xerophthalmia occur in approximately the following order. Night blindness The child cannot see in the dim light of evening (dusk). Families describe how the child falls over things or knocks them over when he or she moves around. The child cannot see to eat. Often there is a local name for night blindness - such as "chicken blindness". It is an important sign because families recognize it and because it can easily be cured. To find out if a child has night blindness, ask the relatives. Night blindness is cured in one to two days by vitamin A. Bitot's spots These are foamy, soapy whitish patches on the white part of the eye. Bitot's spots may not disappear completely after treatment, especially in older children and adults, but they do not affect the sight. Conjunctival xerosis Xerosis means dryness. The conjunctive (the covering of the white part of the eye) looks dry and slightly rough or wrinkled, instead of wet, smooth and shiny. It is difficult to recognize conjunctival xerosis without special training. Bitot's spots, which usually occur at the same time, are easier to see. Conjunctival xerosis is cured in one to two weeks by vitamin A. Active corneal lesions The cornea is the clear part of the eye which you see through, in front of the brown iris. If the cornea is damaged, the person cannot see properly and may be blind. Corneal xerosis The surface of the cornea is cloudy and dry. Some people call this condition "fish scales over the eye". Early corneal xerosis can be cured in one to two weeks. However, it can become more serious very quickly, in hours or days. More serious lesions are incurable. Thus a child with corneal xerosis needs treatment urgently with large doses of vitamin A. Corneal ulcers If xerosis is not treated early enough, ulcers (holes) may form on the surface of the cornea. Vitamin A can cure the ulcers, but usually a scar remains which may affect the eyesight. Keratomalacia It xerosis or ulcers are not treated, the whole cornea becomes cloudy and soft. The cornea may burst and part of the inside of the eye may come out. Often one eye is worse than the other. Giving vitamin A immediately stops keratomalacia becoming worse and may save some sight, especially in the better eye. Corneal scars The cornea is white, and the person can see little through it. There are several causes of corneal scarring, and it can be difficult to know which is responsible. If the family can tell you that the scars appeared after the child had measles or another infection or undernutrition, then they are probably due to vitamin A deficiency.

Source: King and Burgess, 1993.

Prevalence of VAD in affected communities is also assessed by analysis of the level of retinol in the blood serum. However, serum retinol levels are difficult to interpret since most vitamin A is stored in the liver, and ideally it is these stores that should be estimated. Costly laboratory techniques exist for this estimation. Where these techniques are not available, it is better to use an assessment based on food consumption surveys to provide further information on the intake level of vitamin A and of beta-carotene in the diet of specific population groups (IVACG, 1989).

The reasons for low vitamin A intake vary among countries; therefore situational analysis is necessary to understand and subsequently to design and implement appropriate intervention programmes. However, most situations where VAD occurs as a public health problem share some common characteristics. Poverty is in most cases the root cause, as VAD primarily occurs in countries, areas and families that cannot afford the quantity and variety of foods needed to meet their vitamin A requirements. Particular problems include lack of dietary fat and of foods of animal origin that contain preformed vitamin A (beta-carotene) and the seasonal fluctuations in the availability of many beta-carotene-rich fruits and vegetables. Ecological factors are also important, as foods rich in vitamin A require sufficient water supply and/or moderate temperature to grow. An inadequate water supply may often limit home and community gardening and as a consequence the availability of inexpensive sources of vitamin A. Thus countries or parts of countries with long dry periods and relatively constant hot temperatures are more likely to have vitamin A deficiency problems. Poor living conditions and inadequate hygiene and sanitation often contribute to the problem of VAD. Numerous studies have shown a drop in serum vitamin A as a result of infections, and blindness following measles may also be a result of VAD (WHO/UNICEF, 1995).

FAO food balance sheets indicate that the supply of vitamin A has improved in most developing countries over the past 20 years. In the late 1980s countries in the Near East, North Africa and Latin America and the Caribbean achieved levels substantially above the minimum base per caput requirement of 250 µg retinol equivalents (RE) per day and probably above the per caput safe level of intake of 550 µg RE per day. To assess vitamin A supplies in sub-Saharan Africa a clear distinction has to be made between countries in West Africa, where red palm oil is produced, and the rest of the region. Per caput vitamin A supplies in East Africa are generally low and even decreasing. Levels in southern Africa are below the per caput safe level of 550 µg RE per day. In West Africa and the Sahel regions vitamin A supplies are high but decreasing, and VAD does occur. One of the major reasons is that red palm oil is not marketed widely in many of these countries and does not reach vitamin A-deficient areas (see Box 67).

Preventing and combating micronutrient malnutrition through a comprehensive approach

In recent years, many activities to reduce micronutrient deficiency disorders have been implemented in developing countries, but these have mainly consisted of traditional health-based approaches focusing on supplementation, i.e. capsule and pill distribution. Longer-term preventive interventions have also been implemented by the agriculture, education and food technology sectors, but the widespread application of these interventions has been constrained, primarily because of a lack of awareness by donors and affected countries regarding their effectiveness and sustainability and a consequent lack of funds committed to such activities.

Box 67 - The vitamin A supply situation in Africa The vitamin A situation in Africa requires careful examination. First, it is essential to distinguish between those countries where red palm oil is produced - in West Africa - and the other countries. When this is done, it becomes clear that East and southern Africa have very low availability of vitamin A. In southern Africa availability is probably on average below requirements, so that vitamin A deficiency is likely to be widespread. In addition, there are some indications that the overall supply is actually decreasing in East Africa, which would exacerbate the problem. In West Africa and the Sahel the apparently high availability does not preclude the coexistence of deficiency. As noted above, this is related to the fact that red palm oil is not marketed widely in a number of these countries. The retinol supply assessed from food balance sheets should, however, be treated only as potential supply. Effective levels of physiological intake are determined by many factors including the state of maturation of certain fruits and vegetables, effects of dietary fats on the intestinal absorption of vitamin A, and intake of enriched foods. In the period 1986 to 1988, the developing regions of the world derived more than 70 percent of vitamin A from plant sources. These include green leafy vegetables, carrots, various fruits, sweet potatoes and palm oil. In contrast, developed countries obtained only 45 percent of vitamin A from food of vegetable origin. The proportion coming from animal products tends to be higher in higher-income countries.

Source: Adapted from UN ACC/SCN, 1992.

In order to combat micronutrient deficiency diseases effectively and in a sustainable manner, governments and decision-makers need to be made aware of all the different approaches for reducing micronutrient deficiencies. The World Summit for Children, held in New York, USA, in 1990, drew greater attention to micronutrient deficiencies and called for new integrated strategies to solve this problem. The 1992 International Conference on Nutrition translated this awareness into a coherent strategy, making a real commitment to the use of sustainable food- and agriculture-based actions to ensure access to food and increased food consumption by the at-risk groups. The implementation of this strategy will require improved coordination and integration between health measures and activities in food and agriculture and will also require the allocation of adequate resources for undertaking food-based activities.

The strategy of choice to prevent and combat micronutrient malnutrition should be based on promotion of the production and consumption of micronutrient-rich foods, on food fortification and on nutrition education and related activities. This is the only effective and sustainable solution to the problem. Supplementation also has to be considered as a component of the strategy for areas or populations with clinical vitamin A deficiency, but there should be a clear commitment to withdraw this activity (except in special conditions, e.g. where refugee or displaced populations depend on relief foods supplying inadequate micronutrients) as soon as food-based activities are in place and are effectively providing the population at risk with enough foods rich in micronutrients to prevent and control micronutrient deficiencies. The importance of each component of the strategy will vary according to the situation of the country, with account taken especially of the sustainability of the programme, the availability of personnel and cost-effectiveness.

Promoting the production and consumption of micronutrient-rich foods

In many African countries agricultural policies have for the past 30 years largely focused on income generation for the farmer, foreign exchange earnings from exported foods and national food security (see also Chapter 2). Food policies have been most concerned with promoting increased production of staple grains. While all of these considerations are important for good nutrition, food and agriculture policies have done too little to improve dietary diversity and increase consumption. Work is needed in this area, specifically to promote desirable nutrition outcomes through such means as land tenure, diversification of production, access to small-scale credit and nutrition education.

Food and agriculture policies can also directly affect the consumption of micronutrient-rich foods by altering their availability and price. In particular, these policies can promote horticultural crops, legumes, small animals, fish and edible tree crops as well as social forestry and cropping patterns and preservation practices that alleviate seasonal food shortages and lead to greater availability and intakes of micronutrient-rich foods at household level (see also Chapter 5, on food diversification). Nutrition objectives should also be integrated into the agricultural research agenda. Ways of maximizing the micronutrient output of agricultural systems should be explored through research to enhance the big-available micronutrient content of major crops and to develop integrated small-scale farming systems that maximize production of micronutrient-rich crops, small-scale environmentally sustainable livestock enterprises and agro-forestry techniques for the production of both food and fuel (Combs et al., 1996). Horticultural-sector development can be used to increase production of fruits and vegetables, legumes and tree crops bearing edible leaves. In areas with inadequate rainfall, this development can be enabled through the provision of small-scale irrigation facilities and/or groundwater harvesting techniques. Box 68 provides an account of observed relationships between cropping patterns and the prevalence of vitamin A deficiency in Ethiopia as a guide for food-based intervention programmes.

More households could be encouraged to grow dark-green leafy vegetables, such as amaranth, and orange or yellow fruits and vegetables such as pumpkin, papaya and mango for family use. Promotion of home gardens, fish ponds and poultry rearing, as well as small animal production, is also seen as a viable strategy to improve the consumption of beta-carotene and of retinol on a long-term basis. In areas of West Africa where red palm oil is widely consumed there is no deficiency of vitamin A. Promotion of oil-palm cultivation in other climatically suitable areas should be encouraged.

Box 68 - Vitamin A deficiency in Ethiopia: a recommendation for food-based intervention programmes Clinical and biochemical data from the nationwide survey indicated that the prevalence of vitamin A deficiency was very low in the ensete staple areas. Dietary studies carried out previously have shown that ensete foods are supplemented with kale and cheese which can supply provitamin A and vitamin A, respectively. The cereal staple areas, referred to as the cropping zone, and the pastoral areas are those most affected as they have the highest prevalence of vitamin A deficiency. An even higher prevalence of vitamin A deficiency was found in Melkaye village which is in the cereal cropping zone in Hararge Region. This village does have the potential to grow coffee and chat (Khat edulis) which would enable it to have a cash-crop economy. The prevalence of vitamin A deficiency in the area was high not only because of the crops grown but also because of the failure of rains over a six-year period which resulted in total dependence of the inhabitants on relief food supplies. The food distributed contained very little vitamin A. From these studies we can conclude that vitamin A deficiency is a problem of public health significance in the cropping and pastoral zones of the country and was exacerbated in the relief-food-aid-dependent areas. On the other hand, the ensete staple areas are relatively non-affected. Distribution of vitamin A capsules should not overshadow other approaches that could be used to control vitamin A deficiency. Until now, most efforts have been directed towards the use of vitamin A capsules, but food-based intervention programmes are more appropriate in countries like Ethiopia. The relatively low prevalence of vitamin A deficiency in the ensete areas, as a result of the consumption of kale and cheese, provides an indication of the approach that could be followed in combating the problem of vitamin A deficiency. For example, in Kobo and Robi in the cropping area, the prevalence of vitamin A deficiency was not particularly high, probably because of the establishment of small irrigation schemes which enable production of vegetables that are rich in provitamin A.

Source: Wolde-Gebriel et al., 1992

Some green leafy vegetables may also be gathered regularly from wild plants. Early arable weeds are a particularly valuable source of "pot-greens", as they grow very quickly with the first rains and are harvested before there is any serious competition with the growing crops. In addition to these herbaceous plants, a wide variety of trees and shrubs are often used, especially the baobab, Adansonia digitata. Many of these shrubs and trees are identified only by their local names which vary from country to country. In Upper Shaba, former Zaire, it was found that leaves from 50 different tree species were eaten (Malaise and Parent, 1985), and in Swaziland more than half the adults interviewed reported that they ate wild leaves at least twice weekly when they were in season (Ogle and Grivetti, 1985). The nutritional values of selected East African green leafy vegetables are shown in Table 56.

In addition to increases in production, major improvements are also needed in the preservation, processing, distribution and marketing of micronutrient-rich foods to reduce waste, post-harvest losses and the effects of seasonality. Particular attention needs to be paid to marketing of perishable foods. The vitamin content of harvested vegetables and fruits is inevitably substantially lowered, especially if they have been exposed to direct sunlight for extended periods. In harvesting green leaves from legume and root crops, care must be taken to avoid overdepletion of the photosynthetic resources of the plant. Many farmers have developed their own well-tried methods of leaf harvesting that minimize risks of crop reduction for the main food product.

Table 56 - Nutritional values of selected East African green leafy vegetables

Vegetable	Energy (kcal)	Protein (g)	Fat (g)	Calcium (mg)	Iron (mg)	_-carotenea (µg)	Vitamin C (mg)
Amaranth (raw leaves)	45	4.6	0.2	410	8.9	2300	50
Cassava (raw leaves)	90	7.0	1.0	300	7.6	3000	310
Cowpea (raw leaves)	45	4.7	0 3	255	5.7	700	56
Pumpkin (raw leaves)	25	4.0	0.2	475	0.8	1000	80
Sweet potato (raw leaves)	49	4.6	0.2	160	6.2	2 620	70

Source: West, Pepping and Temalilwa. 1988. a 6 µg _-carotene = 1 retinol equivalent (RE).

In general, traditional methods for processing, preservation and storage of vegetables cause significant losses of nutrients. Much food is wasted because of the lack of appropriate village-level food preservation technologies. However, there is good evidence that careful preservation and processing helps fruit, especially mangoes, retain good vitamin A activity. Results of a study from Senegal show that sun-dried mangoes can be an excellent source of both beta-carotene and vitamin C as well as a relatively good source of iron (Ranking, Hopkinson and Diop, 1989). Beta-carotene retention after solar drying using specially designed low-cost solar dryers was found to be much higher than retention following traditional methods of drying (see Chapter 5, Box 24). Solar drying can be readily adapted to developing environments. It offers good potential for improving family nutrition, especially during seasonal shortages of vegetables and fruits, and for improving family income, since dried foods can fetch a good market price.

Nutrition education is a complementary activity and is fundamental for ensuring the effectiveness of a food-based approach. The consumer should understand that in order to achieve and maintain good health, several principles should be followed. These include eating a variety of food; preparing and eating diets to meet physiological requirements; maintaining food safety and hygiene in food preparation; and finally keeping active and fit. These basic messages are part of FAO's nutrition education and information package for the general public Get the best from your food (FAO, 1995e). The package acknowledges that while local food habits and traditional dietary customs and practices can vary, virtually all local food systems can supply the food necessary to prevent micronutrient malnutrition. A comprehensive list of different food-based approaches and activities that can be implemented to increase the supply and consumption of micronutrient-rich foods in the community is given in Box 69. See also Chapter 9 for details on nutrition education.

Food fortification

Food fortification - the addition of essential nutrients to foods offers another element of the food-based approach to the prevention and control of dietary micronutrient deficiencies. Fortification is not the appropriate solution in all situations, and it must generally be used in combination with other techniques in order to obtain the best results. It may be especially useful and appropriate in those cases (e.g. IDD) where deficiencies cannot be corrected through growing or purchasing fresh and high-quality nutritious foods (fruits, vegetables, meat and fish) or in emergency situations. Fortification should be viewed as part of a range of measures influencing the quality of food, including improved agricultural practices, better processing and storage methods and consumer education.

Several foods - cereal products, rice, salt, sugar, milk, oil and condiments - have been identified as vehicles for fortification. In industrialized countries a wide range of foods are fortified with many different micronutrients including vitamin A, vitamin B complex, iron and iodine. Iodization of salt has been highly effective in both developed and developing countries for decades. Cooking oil is an obvious candidate for fortification, but as indicated in the section on African diets in Chapter 7, the consumption of oils and fats in the African diet is usually low, especially for poorer consumers, as these items are expensive. Vitamin A fortification of sugar was successfully implemented in Guatemala, and after years of interruption it has been resumed. In the United Republic of Tanzania efforts are under way to fortify tea with vitamin A. The World Food Programme (WFP), the European Community (EC), the United States Agency for International Development (USAID) and other national and international organizations involved in humanitarian assistance distribute foods fortified with a wide range of micronutrients. These include dried skimmed milk powder enriched with vitamin A and various blended foods [e.g. corn (maize)/soybean/milk (CSM)] that are targeted for distribution to children and pregnant and lactating women.

Box 69 - Food-based approaches to micronutrient deficiency The following list presents possible food-based approaches and activities that may be taken into account to combat micronutrient deficiencies. Activities should be selected based on geographic, demographic and socio-economic conditions. Community participation in design and implementation is a crucial component of successful, sustainable programmes. Agriculture · Train extension agents and other trainers about food and nutrition. · Train farmers to make them aware that growing micronutrient-rich plants not only enriches their families' daily diet but may bring extra income. · Develop home, community and school gardens. · Promote mixed farming systems that supply families with a more varied diet. · Introduce higher-yielding vitamin A-rich varieties. · Promote fruit and vegetable cultivation throughout the year to overcome seasonality of food supply. · Support small-scale animal husbandry as a source of micronutrient-rich food and extra income. · Promote aquaculture, including skill training for community members and extension agents. · Prevent post-harvest losses through proper food handling, transport, storage, preservation or processing techniques and facilities. · Strengthen collection of horticultural statistics including those for micronutrient-rich and traditional crops (vegetables and fruit). · Integrate micronutrient activities into rural and agricultural development programmes, horticulture production projects, women's activities, projects to reduce food losses, communication and information programmes and community forestry and fishery activities. · Establish small-scale credit systems accessible to low-income producers. Education and training · Prepare materials or guidelines on safer methods of processing and preserving micronutrient-rich foods. These materials and guidelines should be addressed to the general public as well as specifically to women, farmers, small-scale merchants and community workers. · Train nutrition or agricultural extension workers, community workers, health personnel, religious leaders, schoolteachers, students, women and family members on the following topics: - the importance of vitamin A, iron, vitamin C and fat in the diet and identification of micronutrient-rich foods; - safe methods of processing and preservation of micronutrient-rich foods, e.g. cooking methods, storage places and use of solar dryers; - home gardening as a rich source of vitamin A, vitamin C and other micronutrients; - small-scale animal husbandry and aquaculture as rich sources of vitamin A, iron and calcium; - the importance of using salt fortified with iodine. · Integrate nutrition, with special emphasis on prevention of micronutrient deficiencies, into curricula of primary and secondary schools as well as teachers' training colleges and training institutes responsible for adult education and youth groups. · Promote breastfeeding by emphasizing the richness of mother's milk and the importance of breastmilk in preventing infectious diseases. · Use social marketing to promote production and consumption of micronutrient-rich foods. Marketing · Establish local markets to ensure availability of micronutrient-rich foods. · Improve the local infrastructure system to allow distribution of micronutrient-rich foods even in remote areas. · Provide economic credits to women's groups producing and marketing fruit and vegetables. Research · Assess food availability of micronutrient-rich foods, including traditional foods in local markets. · Assess food consumption patterns of different age groups and reasons why and when certain foods are not eaten. · Evaluate existing nutrition interventions. · Identify international and national organizations, non-governmental organizations (NGOs), voluntary groups, women's groups and others working on micronutrient programmes. · Identify traditional foods rich in micronutrients and develop national food composition tables. · Support research institutes developing plant varieties with higher vitamin A and other micronutrient values. · Evaluate training curricula for nutrition and health staff regarding micronutrients. Food industry, trade and commerce · Fortify appropriate foods with needed micronutrients and promote these foods to specific groups that lack access to high-quality, nutritious foods. · Package micronutrient-rich foods economically for poor consumer groups. · Improve labelling and advertising of micronutrient-rich processed foods. · Institute food regulatory systems to enable nutritionally appropriate fortification. · Train food inspectors and food control laboratories to analyse fortified foods for the added micronutrients. Special considerations · Set up intersectoral groups to coordinate activities among sectors. · Provide information about the importance of preventing micronutrient deficiencies to decision- and policy-makers in commerce, education and communications. · Organize women's groups to give special attention to home production and preparation and to small-scale animal rearing. · Involve the community in programme design, implementation and evaluation. · Involve NGOs in providing technical support and training. · Provide short-term training for professional staff. · Develop or strengthen existing surveillance systems to monitor the effectiveness of micronutrient programmes.

Source: FAO/ILSI, 1997.

Fortification does not usually require changes in people's dietary habits. Although it may be sustainable over a long period and is often considered a cost-effective means of overcoming micronutrient malnutrition (World Bank, 1994), caution should be applied in adopting this strategy, as the maintenance of fortification programmes in developing countries in the past has often required long-term financing by donor governments.

Ensuring that fortification is effective and sustainable is not simple. To be effective, fortification requires informed decisions about such aspects as foods that are suitable as vehicles for fortification (i.e. foods that are consumed widely and in sufficient quantities); the nutrient to be added (i.e. the fortificant); the process of fortification to be adopted, for example mixing, coating, infusion or extrusion; and the proper level of enrichment. It is also important that the identified vehicle be consumed in roughly constant quantities throughout the year by the majority of the population in need and that the addition of fortificants at the required level does not affect the organoleptic qualities of the food. In some countries it may be difficult impossible to identify a food item that is suitable for fortification, especially in the non-industrialized countries of Africa, where only salt has been found to be suitable for wide distribution. Attention must be given to the price and marketing systems for fortified foods to enable the poorest and most affected population groups to obtain them. Key steps required in planning a national fortification programme are listed in Box 70.

Every fortification programme needs to monitor carefully the health implications of the various fortificants from different sources that may be consumed by an individual. In many developing countries supplements of micronutrients in the form of pills or capsules are provided to populations at risk, i.e. small children and pregnant women, under various conditions and in different programmes. It must be ensured that the cumulative intake does not exceed the safe level of intake, thus causing toxicity. In addition, in some cases fortification programmes may need to be accompanied by nutrition education to avoid the risk of overconsumption of the carrier. This is especially so in the case of salt and sugar, whose overconsumption can contribute to causing or can exacerbate noncommunicable diet-related diseases in at-risk groups (particularly persons suffering from cardiovascular disease, high blood pressure or diabetes).

To ensure that fortification is effective and sustainable, that the health of the consumer is protected and that fortified foods comply with certain measures of quality, it is essential that a surveillance system be set up to monitor the dietary intake of consumers. A food control system also needs to be established to ensure that fortified foods are monitored officially through inspection and analysis for compliance with nationally accepted quality and safety requirements. Without well-functioning dietary surveillance and food control systems, it is almost impossible to have an effective national micronutrient fortification programme.

Box 70 - Steps in the development of food fortification programmes The steps in developing a fortification programme include the following: · Determine the prevalence of the micronutrient deficiency. · Segment the population if prevalence indicates the need. · Determine the micronutrient intake from a dietary survey. · Obtain consumption data for potential vehicles. · Determine micronutrient availability from the typical diet. · Seek government Support (policy-makers and legislators). · Seek food industry support. · Assess the status of potential vehicles and the processing industry chain (including raw material supply and product marketing). · Choose the type and amount of micronutrient fortificants or mixes. · Develop the fortification technology. · Perform studies on interactions, potency, stability, storage and organoleptic quality of the fortified product. · Determine big-availability of the fortified food. · Conduct field trials to determine efficacy and effectiveness. · Develop standards for the fortified foods. · Define final product and packaging and labelling legislation. · Develop legislation and regulation for mandatory compliance. · Promote campaigns to improve consumer acceptance.

Source: Lofti et al., 1996.

Health system improvements and medicinal supplementation

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 of growth and development. In a good health system, personnel are trained to promote preventive health care, to detect and treat nutritional deficiencies, to manage pharmaceuticals efficiently and, most importantly, to reach out to the most vulnerable economic groups. To treat severe deficiency states, health care providers need to be able to diagnose the deficiencies, to provide the appropriate therapeutic pharmaceutical supplies, equipment and counselling materials and to have access to a referral system for intractable or severe cases.

Although vitamin A deficiency can be treated by high-dose vitamin A capsules, this strategy must be regarded as a therapeutic or short-term intervention for at-risk groups in areas of endemic VAD. In these areas hospitals and outpatient clinics can provide supplementary doses of vitamin A to all children with cases of diarrhoea, malnutrition and measles. Vitamin A may also be given to malnourished mothers immediately after delivery, both for their own health and to ensure an adequate level of the vitamin in their breastmilk, following WHO guidelines (WHO/UNICEF/IVACG Task Force, 1997).

Large-scale prophylactic supplementation programmes using high doses of vitamin A for prevention of the deficiency are not recommended. They tend to be expensive and unsustainable, to foster dependency on donor support and to divert political and government support away from establishment of more sustainable, food-based approaches. Serious health complications can also arise from the use of large doses of vitamins, ranging from birth defects in infants if the treatment is given to women who are pregnant or could soon become pregnant, to toxicity in infants (and possible retardation of their brain development) if it is given in early infancy (de Francisco et al., 1993).

Often the actual cost of supplementation programmes goes much beyond the cost of the supplement itself, which has been estimated at less than US$0.02 per person from the producer, although very few studies have evaluated the cost of distributing capsules (if delivered at all) in remote areas where the populations that are most at risk tend to be located.

A 1989 evaluation found that a large-scale supplementation programme initiated in Bangladesh in 1973 as an interim measure to prevent and control VAD was not effective in reducing the problem (Greiner, 1992). Bangladesh still faces a very high rate of VAD. Experiences in many other Asian and African countries have shown similar problems to those in Bangladesh. Although outreach has often been very positive at the onset of programmes (reaching up to 75 percent of the target population), after two or three years the percentage of the population reached has markedly declined (only 30 to 40 percent of the target population). The decline is not surprising, especially considering that large-scale programmes are often generously subsidized during the initial stages by donor agencies or governments, which both supply capsules free of charge and provide logistical support such as vehicles, fuel and staff allowances. Once such support is reduced or withdrawn, developing countries often do not have the resources or the health infrastructure extending to more remote areas to sustain such programmes in the medium to long term.

By giving priority to strategies based on pharmaceutical supplements, donor agencies have often given government technical staff and policy-makers a false signal regarding the crucial importance of food-based actions, continuing to delay the necessary shift in their approach towards food-based solutions. This is damaging in the long run.

Emphasis should now be given to food-based activities, namely the production and consumption of micronutrient-rich foods and fortification of foods, especially with iron and iodine. The main types of strategies for overcoming the three micronutrient deficiencies discussed in this chapter and possible interventions, including the main types of foods involved in dietary diversification and food fortification, are summarized in Tables 57 and 58.

The major micronutrient deficiency diseases, including xerophthalmia, iron deficiency anaemia and endemic goitre, could all be largely controlled if present knowledge were applied and sufficient resources were provided. PEM, which often occurs in association with micronutrient deficiencies, also needs to be tackled. In addition to implementing programmes aimed specifically at combating and preventing micronutrient deficiencies, there is a need to develop comprehensive food security programmes and to promote broad-based development in agriculture, including fisheries, forestry and related rural industries, so as to create better food supplies and access to food through stable and increased income and employment. The prevalence of all four major nutritional deficiency conditions could be greatly reduced by increased attention, at policy level, to consumer demand and to household food security aspects of agricultural policies, research and investment programmes.

Table 57 - Main types of strategies for overcoming micronutrient deficiencies

Deficiency	Dietary diversification	Fortification	Supplementation	Public health and control measures
Iodine deficiency disorders	Promotion of the consumption of iodine-rich foods	Production, distribution and consumption of fortified foods	Delivery of supplements to target group population (i.e. primarily at-risk groups such as refugees)	Improvement of primary health care
		Food quality control, legislation and enforcement		Improved processing of goitrogenic foods
Vitamin A deficiency	Promotion of the production and consumption of vitamin A-rich foods	Production, distribution and consumption of fortified foods	Delivery of supplements to target group population (i.e. primarily at-risk groups such as refugees)	Improvement of primary hearth care
	Nutrition education	Food quality control, legislation and enforcement		Prevention of infections:
	Improved distribution system			- environmental health
	Improved food preservation and processing			- immunization
				- oral rehydration therapy
				- antiparasitic measures
Anaemia	Promotion of the production and consumption of iron-rich foods	Production, distribution and consumption of fortified foods	Delivery of supplements to target group population (i.e. primarily at-risk groups such as refugees)	Improvement of primary health care
	Nutrition education	Food quality control, legislation and enforcement		Prevention of infections:
	Improved distribution system			- environmental
	Improved food preservation and processing			health
				- immunization
				- oral rehydration therapy
				- antiparasitic measures (especially against hookworm and malaria)

Source: Adapted from FAO/WHO, 1992e.

Table 58 - Main types of foods and supplements in interventions for overcoming micronutrient deficiencies

Deficiency	Dietary diversification	Fortification	Supplementation
lodine deficiency disorders	Seafoods	Salt	Iodized oil
	Other iodine-containing foods (reduce goitrogens)	Water	Potassium iodide tablets
		Baby foods
		Condiments
		Flour
		Milk
Vitamin A deficiency	Green leafy vegetables	Sugar	Capsules (oil) in massive or small doses
	Orange-coloured vegetables and fruits	Salt
	Red palm oil	Milk powder
	Animal foods	Baby foods
	Breastmilk	Condiments
Anaemia	Green lealy vegetables	Salt	Iron/folate tablets
	Pulses	Cereals or cereal flour	Parenteral iron
	Fruits and vegetables (vitamin C)	Condiments
	Liver, red meat (avoid tea and coffee with meals)

Source: FAO/WHO, 1992e.