Interventions
Clearly, growth faltering and micronutrient deficiency disorders are prevalent, have deleterious consequences for children's health and development, and are primary contributors to the global burden of disease. Economic development is not the only path to solving childhood undernutrition. Improvements in family income may not translate into increased food intakes because the income elasticity for caloric intake is relatively low. The effects on micronutrient deficiencies might be greater if the food sources of those nutrients (meat, seafood, eggs, fortified food products) were more sensitive to income increases and if children had access to those foods. Price subsidies may reduce undernutrition in young children if targeted to foods consumed by them; the potential contribution of price subsidies to family nutrition is discussed elsewhere (see chapter 11). This chapter focuses on specific public health measures that are intended to address the problems directly. Progress has been made in some areas, but the current magnitude of the problems and of the associated disease burden underscore the need for more investment in nutritional interventions.
Growth Faltering and Childhood Stunting
Infants and young children falter in their growth because of inadequate dietary intakes and recurrent infectious diseases, which reduce appetite, increase metabolic requirements, and increase nutrient loss. Even though this problem is understood, progress to reduce malnutrition has been slow. Over time, thinking on how to reduce growth faltering and childhood stunting has shifted. Whereas previous efforts focused almost exclusively on identifying and rehabilitating severely malnourished children, current efforts emphasize prevention through combined nutritional and disease prevention and treatment interventions.
Initially, these efforts to prevent undernutrition focused on diseases rather than on improved child feeding practices as such. However, according to Becker, Black, and Brown (1991), despite the devastating effects of illness on nutritional status, improving dietary intakes is more effective than disease prevention efforts in reducing undernutrition. Because of dramatic reductions in appetite during illness, efforts to improve dietary intakes initially focused on maintaining energy intakes despite anorexia and on increasing intakes during recuperation, when appetite may be normal or high. More recent interventions aim at feeding healthy children optimal diets, which includes paying attention to dietary quality. Finally, some have argued that, for nutritional advice to be effective, it needs to be provided alongside growth monitoring and promotion; however, it is increasingly recognized that messages for prevention are largely universal and that integrated growth monitoring and promotion are not the only model for service delivery.
Promotion of Optimal Feeding of Infants and Young Children
Much of the early focus on optimal feeding was on breastfeeding, which should be immediate and exclusive until six months of age. At that time nutritious and safe foods should be added to a diet that is still based on breast milk until early in the second year of life. A consensus has been reached that six months is the recommended duration of exclusive breastfeeding (WHO 2002) and that the total duration is a decision left to the mother.
Multiple approaches exist to promote the initiation of breastfeeding and to prolong exclusive breastfeeding—health education; professional support; lay support; health sector changes (for example, infant friendly hospitals); and media campaigns—through health facilities and community programs. A recent Cochrane review estimates the potential effectiveness of these approaches (Sikorski and others 2002). Women who received any form of support for breastfeeding were 22 percent less likely to stop exclusive breastfeeding, and women who received lay support, in particular, were 34 percent less likely to stop exclusive breastfeeding. Substantial evidence indicates that interventions can be effective in prolonging breastfeeding and exclusive breastfeeding and that operational research is needed for program implementation and sustainability. If such programs were fully successful, they would reduce deaths in children under five by 13 percent (Jones and others 2003).
Complementary feeding is the process of introducing other foods and liquids into the child's diet when breast milk alone is no longer sufficient to meet nutritional requirements. According to Brown, Dewey, and Allen (1998), complementary feeding practices are suboptimal from several perspectives:
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Complementary foods are introduced too early or too late.
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Foods are served too infrequently or in insufficient amounts, or their consistency or energy density is inappropriate.
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The micronutrient content of foods is inadequate to meet the child's needs, or other factors in the diet impair the absorption of foods.
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Microbial contamination may occur.
In addition, because children often do not eat all the food offered to them, interaction between the caregiver and the child, along with other psychosocial aspects of care during feeding, requires attention. The amount of complementary food a child needs depends on breast milk intake. Guidelines are available for determining energy and nutrient intakes from complementary foods, given breast milk intakes (Dewey and Brown 2003).
Several reviews of the multiple approaches to improving infant and young child feeding practices are available (Allen and Gillespie 2001; Caulfield, Huffman, and Piwoz 1999; Dewey 2002; Hill, Kirkwood, and Edmond 2004; Swindale and others 2004). Caulfield, Huffman, and Piwoz (1999) review 16 programs in 14 countries to improve dietary intakes of infants 6 to 12 months of age. The programs were designed to promote exclusive breastfeeding and appropriate feeding during illness up to age three, and the content and approaches reflected current thinking regarding nutrition and behavior change. The approaches employed included using the mass media to reach both caregivers and the population as a whole to change cultural norms about complementary feeding and using one-on-one or small group interactions with community health workers to provide individualized information and support.
Most of the projects achieved good coverage (50 to 70 percent), with rates varying depending on the communication strategy. They resulted in large shifts in maternal knowledge and attitudes and changes in infant feeding practices. In the few programs assessing dietary intakes, intakes improved by 70 to 165 kilocalories per day. Differences in nutritional status at 12 months indicated weight-for-age and height-for-age gains of 0.24 to 0.87 SD. Even with a 50 percent overestimation of the effects, the effect of such programs could translate into tangible reductions in malnutrition and attributable mortality. In addition, these calculations do not consider the cumulative reduction in malnutrition from programs that benefit children's growth into the second and third years of life. Jones and others (2003) use the results of the analysis, along with knowledge of the relationship between underweight and child mortality, to estimate that programs to promote complementary feeding could reduce by 6 percent the deaths of children under five in developing countries.
Many programs provide supplemental food to participants either to provide them an incentive for participating in other activities (to offset time costs and increase consumer demand for preventive services) or to rehabilitate severely malnourished children. Although the latter approach is traditionally considered for supplemental food programs, the former approach is more common. Indeed, India's Integrated Child Development Services Program, the world's largest supplemental food program, plans to shift from rehabilitation to the use of supplemental food as a "magnet" for providing other integrated child development services (Kapil 2002). No consensus exists on when or how to include supplemental food to reduce undernutrition, and inefficient targeting is frequently a key constraint to effectiveness. Swindale and others' (2004) review of the effectiveness of food-assisted child survival programs concludes that such programs are reducing malnutrition by 2.0 to 2.5 percent per year.
Despite evidence of the effectiveness of nutritional interventions in improving feeding practices and preventing undernutrition, few programs take a comprehensive approach toward optimizing infant feeding, perhaps because of a lack of consensus on the key components of a comprehensive strategy. In 2002, participants at a WHO consultation developed 10 guiding principles for optimal feeding of the breastfed child (PAHO and WHO 2003). These principles, outlined in box 28.1, build on lessons from previous programmatic efforts such as those reviewed here and provide a basis for designing comprehensive programs to reduce malnutrition. The international public health community faces the challenge of implementing and evaluating these approaches.
Disease Control and Prevention
Interventions to prevent or decrease malnutrition or infectious disease are expected to decrease child mortality, and interventions that accomplish both will have the greatest effect (Pelletier, Frongillo, and Habicht 1993). This subsection considers the potential for disease control and prevention efforts to reduce undernutrition in young children.
Malaria is responsible for a large portion of childhood mortality in Sub-Saharan Africa. The effect of undernutrition on susceptibility to malaria has been discussed at length elsewhere (Caulfield, Richard, and Black 2004), but the nutritional deficiencies resulting from malaria have been insufficiently explored. Insecticide-treated bednets have been shown to prevent clinical episodes of malaria and decrease the prevalence of anemia in children (Lengeler 2003). Improvements in growth have also been documented.
Water, sanitation, and hygiene interventions decrease childhood malnutrition primarily by preventing diarrheal disease (Checkley and others 2004). Hand-washing interventions can reduce the risk of diarrheal diseases by about 45 percent. Hand-washing interventions can be included in water and sanitation programs or can exist as a single intervention, and they are both effective and cost-effective (Borghi and others 2002).
Vitamin A Deficiency
Even though the consequences of VAD had been defined by 1920, it was 1986 when vitamin A interventions were rigorously studied in a large, controlled community trial (Sommer and West 1996). A number of other community trials soon also demonstrated a significant decrease in child mortality with vitamin A supplementation (Beaton and others 1993). Supplementation can alleviate acute VAD quickly, whereas long-term strategies incorporate fortification and dietary diversification.
Supplementation can be either a curative or a preventive measure. If an individual presents with ocular symptoms of VAD, supplementation is part of the usual standard of care. Beyond the use of supplementation for symptoms that result directly from deficiency, its use as part of the treatment regimen for measles or severe malnutrition can improve health outcomes. In deficient areas, high-dose oral supplementation is recommended every four to six months for children under five and is highly efficacious in reducing ocular effects as well as mortality (Sommer and West 1996). A meta-analysis of controlled trials in children demonstrated a 23 percent reduction in mortality (Beaton and others 1993). High-dose vitamin A supplements are considered safe for infants younger than six months. Several studies suggest that giving vitamin A within 48 hours of birth reduces mortality in the first three months by 21 to 74 percent (D. Ross 2002).
[Box 28.1]
A variety of foodstuffs have been fortified with vitamin A, including oil, monosodium glutamate, butter, wheat flour, sugar, and rice. Fortified white sugar has been successful in reducing VAD prevalence in Central America. In El Salvador and Guatemala, where fortified sugar is the primary source of vitamin A, it accounts for approximately 30 percent of the recommended dietary intake (RDI). Fortification of monosodium glutamate with vitamin A has been demonstrated to be biologically efficacious. Even though program implementation was flawed by unacceptable cost, discoloration of the monosodium glutamate, and packaging problems, indicators of VAD declined significantly during periods of fortification in both Indonesia and the Philippines (Dary and Mora 2002).
Vitamin A intakes can also be improved through dietary diversification, either by educating communities about important sources of vitamin A and beta-carotene that are available in the local diet or by increasing economic prosperity so that individuals have additional funds to spend on a wider variety of food. Education alone has not been demonstrated to affect the degree of VAD in a community, but it can be a powerful tool when incorporated in a broader strategy that also includes supplementation and fortification (Sommer and West 1996).
Iron Deficiency
Despite the public health community's enduring interest in preventing and treating iron deficiency anemia, little evidence suggests that the problem has been reduced. Indeed, in some regions the opposite may be true. From the 1970s to the 1980s, the iron density of people's diets decreased in every region except the Near East and North Africa as iron-poor cereals displaced legumes. During much of this period, iron deficiency anemia increased in South Asia and Sub-Saharan Africa, where the problem is most severe (Stoltzfus, Mullany, and Black 2004). Goals for reducing iron deficiency anemia were articulated for the 1990s at the 1990 World Summit for Children, and many countries adopted policies for providing supplementation for young children; however, few large programs have been developed to eliminate the problem.
The explanations for this failure to act include doubts among both scientific program planners and policy makers about the causes and consequences of iron deficiency and anemia; lack of political commitment; inadequate program planning, including mobilization and training of health staff members; insufficient community involvement; and, in particular, inherent difficulties with prolonged adherence to daily supplementation (Stoltzfus, Mullany, and Black 2004). Despite this bleak picture, guidelines for supplementation have been formulated for children ages 6 to 24 months and for low birth-weight infants beginning at 2 months (Stoltzfus and Dreyfuss 1998). Also, various scientific documents synthesize and communicate current knowledge about the consequences of iron deficiency anemia and programming efforts.
Ample evidence indicates that iron deficiency is the principal cause of anemia in children; that iron supplements are efficacious in preventing and treating iron deficiency anemia, increasing hemoglobin concentrations by about 1 gram per deciliter on average in controlled trials; and that supplements reduce severe anemia even in malarious areas. The contribution of parasitic infections such as malaria and hookworm to anemia does not negate the usefulness of iron supplements; rather it underscores the need for multiple inputs to prevent severe anemia, given the risks of transfusion. Although current recommendations indicate daily supplements, less frequent delivery, such as intermittently or weekly, is commanding interest. Beaton and McCabe's (1999) meta-analysis concludes that both daily and weekly supplementation are efficacious if adherence is good.
In many countries, iron fortification of foods is the principal strategy for reducing iron deficiency and anemia. Fortified foodstuffs include wheat and maize flours, noodles, sugar, condiments, and complementary foods and milk for infants and children. Efficacy studies indicate the potential of fortification to increase iron intakes and reduce anemia, and effectiveness trials in Chile (dry milk for infants), Ghana (complementary food for young children), Guatemala (sugar), India (salt), Mexico (fortified weaning food and dry milk), and Republica Bolivariana de Venezuela (maize and wheat) have found improvements in hemoglobin concentration or reductions in anemia prevalence (Allen and Gillespie 2001; Rivera and others 2004). Nevertheless, few national iron fortification programs have evaluation results that are without controversy. Yip and Ramakrishnan (2002) argue that the strongest examples of the potential for fortification are found in the Chilean program of fortified dry milk for infants and in the U.S. program of iron-fortified infant cereals. A randomized trial in Mexico of a poverty alleviation program that distributes a complementary food fortified with multiple micronutrients, including iron, found positive effects on anemia rates (Rivera and others 2004). Evaluations of newly implemented iron fortification programs should gauge their contribution to anemia prevention.
Newer strategies, such as sprinkles (powders), spreads, or foodlets (a hybrid of a food and a tablet), appear promising, particularly for regions where the infrastructure will not support more traditional forms of fortification (Zlotkin and others 2003). Processed complementary foods and beverages offer additional vehicles for reducing iron and other micronutrient deficiencies and promoting well-being (Solon and others 2003). Implementing such strategies and documenting their cost-effectiveness are important activities for the next few years.
In many settings, promoting iron-rich organ meats and animal products and undertaking other food-based strategies may increase iron intakes and contribute to anemia reduction. Such approaches have been promoted for many years, but research is still needed to document their efficacy and effectiveness (Ruel and Levin 2000).
Iodine Deficiency Disorders
Interventions to diminish iodine deficiency using either supplementation or fortification are both efficacious and inexpensive, and WHO, the United Nations Children's Fund, and the International Council for the Control of Iodine Deficiency Disorders have pledged to eliminate iodine deficiency and the spectrum of IDD.
For regions with severe endemic iodine deficiency, high-dose iodine supplementation is indicated while longer-term solutions are put into place. Iodized oil and iodide tablets are the most common means of direct administration. Injections of iodized oil have been used with much success to decrease the prevalence of IDD and have been shown to be effective for three to four years, depending on the dosage (Hetzel 1989). Although injected oil is effective, it is also expensive, requires trained personnel to administer, and carries the risk of infectious disease transmission from contaminated needles. Because of those drawbacks, researchers began exploring oral administration as an alternative. Oral administration of iodized oil in liquid and tablet form has been successful in the long-term correction of clinical deficiency, and in Indonesia, oral administration was associated with a reduction in infant mortality (Cobra and others 1997).
Iodized or iodated salt is the primary strategy for correcting iodine deficiency because of the nearly universal consumption of salt regardless of socioeconomic status; the lack of an effect on consistency, color, or taste from the addition of iodine; and the limited number of producers in many countries. Large-scale salt fortification has been highly successful in many countries, and of the 130 countries with iodine deficiency, 75 percent have laws mandating salt iodization. The goal of universal salt iodization for consumption by both humans and livestock in all countries with endemic iodine deficiency was set at the 1990 World Summit for Children (WHO, UNICEF, and ICCIDD 2001). Some populations do not easily embrace salt iodization because of cultural preferences or because they have an ample supply of unprocessed salt, so other means of fortification are needed. One promising option is to add potassium iodate to irrigation water.
Zinc Deficiency
Although zinc deficiency is likely widespread and even mild deficiency probably has significant health consequences, few interventions have been developed to combat it in developing countries. Possible interventions include supplementation, fortification, and dietary diversification or modification. The strong evidence that the use of zinc supplements given during and for a short time after diarrhea improves the outcome of that episode and prevents future episodes has led to the recommendation that zinc, along with increased fluids and continued feeding, be used to treat all episodes of acute diarrhea (WHO and UNICEF 2004). Substantial efforts are under way to initiate programs in developing countries. Prophylactic zinc supplementation also improves growth and reduces diarrhea incidence (International Zinc Nutrition Consultative Group 2004).
Fortification interventions include the traditional method of adding zinc to a commercial food, consumer fortification using sprinkles, and plant-breeding techniques. For example, Mexico has introduced several large-scale programs, including the fortification of maize and wheat flours and the distribution of fortified complementary food and fortified milk to low-income children (Rivera and Sepulveda 2003). Researchers are investigating the possibility of home fortification of food using sprinkles containing iron and zinc (Zlotkin and others 2003), but further research is needed to determine whether sprinkles are a viable option. Through plant breeding and genetic engineering, staple crops may be made to contain more zinc or less phytate, resulting in increased zinc bioavailability (Ruel and Bouis 1998). Other dietary strategies target food preparation techniques, such as fermentation of unrefined flour to increase zinc bioavailability.
