Prevention of Micronutrient Deficiencies Tools for Policymakers and Public Health Workers (1998) / Chapter Skim
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4 PREVENTION OF VITAMIN A DEFICIENCY
4 PREVENTION OF VITAMIN A DEFICIENCY
Pages 103-166
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From page 103... ...
The inability to see well in dim illumination (night blindness) is a symptom recorded in ancient Egyptian, Greek, and Assyrian medical literature and, more recently, in the writings of European physicians.
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From page 104... ...
Where eye signs are not evident, biochemical deficiency-that is, subclinical deficiency is also believed to contribute to mortality risk. In free-living populations, however, an unequivocal tie to the incidence of infectious morbidity has not been established.
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From page 105... ...
, into extrauterine life at the low end of the continuum of vitamin A status. That position may be rapidly augmented postnatally in infants fed vitamin A-rich colostrum and early breast milk (Chappell et al., 1985)
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From page 106... ...
106 sit ._ ._ ._ ._ i< ._ t, ._ PREVENTION OF MICRONUTRIENT DEFICIENCIES Toxic Cell Death Pharmacologic / ~,~ Normal _ Deficient ~ / Ad, Decreased Mitosis I' Stimulate Mitosis ~;~. Cease Mitosis Death Hepatotoxicity~ Bone Fractures' Hemorrhages' Bone Exostoses Alopecia' Eczema Erv theme' Normal Night Blindness Xerophthalmia CSFI, Increase' Keratin izatio' Inanitions ~· ~· ~ 0 100 1.000 10,000 100.000 Vitamin A Intake /kg body wt/day FIGURE 4-l The logarithmic plot of vitamin A intake is depicted as a function of the biological response of man and animals in terms of deficiency, normalcy, and toxicity.
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From page 107... ...
Extent of the Problem Since the debilitating and sometimes fatal link of VAD to health is wellestablished, and effective and relatively inexpensive food sources and synthetic vitamin A are available for VAD prevention and control, why does a global public health problem persist? Clearly the fault lies in the application of insufficient or ineffective knowledge to the implementation of programs to rectify uneven resource distribution among and within affected populations.
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From page 108... ...
Although growth rates decline sharply during infancy, decreasing the requirement for vitamin A per kilogram of body weight, the absolute quantity of the vitamin needed daily increases with growing total body mass (see Figure 4-2, based on FAD/WHO, 1988~. If average dietary vitamin A intake from food progressively increases with body mass, body stores are likely to increase by small increments with advancing age.
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From page 109... ...
The bioavailability of the provitamin A carotenoids from plants is greatly influenced by the nature of the embedding matrix (i.e., fibrous, dark green leafy vegetables tDGLV] or soft-fleshed yellow/orange vegetables and fruits)
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From page 110... ...
Cultural Factors Food habits and taboos often restrict consumption of potentially good food sources of vitamin A, such as mangoes and green leafy vegetables. Culturespecific practices in the feeding of children, adolescents, and pregnant and lactating women are common (Chen, 1972; Johns et al., 1992; Mele et al., 1991~.
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From page 111... ...
remain appropriate for identifying populations at high risk of vitamin A-related, blinding malnutrition-populations to the far left of the vitamin A status continuum (Figure 4-1~. They are inadequate, however, for identifying populations with subclinical deficiency tissue concentrations of vitamin A low enough to have adverse health consequences, even in the absence of xerophthalmia, WHO's current definition of VAD (WHO, 1996a)
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From page 112... ...
Where it is not possible to obtain two biological indicators, WHO suggests that one such indicator should be supported by a composite of at least four of the indirect demographic and ecological risk factors given in Tables 4-3A and 43B. Two of the four indirect indicators should be related to nutrition and diet (Table 4-3A)
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From page 113... ...
In such situations, outcomes derived from metabolic and/or controlled community studies lend credence to causative inferences from similar outcomes of interventions implemented in less rigorously controlled community studies. The inability to perform biological evaluations alone should not prevent initiation of, or stop, VAD control programs when and where such programs are needed.
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From page 114... ...
Food availability Market Household Dietary patterns 6-71 months; children Pregnant/lactating women Semi-quantitative/qualitative food frequency Suggested Prevalence >50% not receiving breast milk <75% receiving vitamin A-containing foods in addition to breast milk, 3 times/week 230% 28% 215% DGLVs unavailable 26 months/yr <75 % households consume vitamin A-rich foods 3 times/week <75% consume vitamin A-rich foods at least 3 times/week Foods of high vitamin A content eaten <3 times/week NOTE: The suggested prevalence cutoff levels are arbitrary. The group of indicators, however, should be given greater weight in identifying high-risk populations than is given to the other ecological indicators noted below.
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From page 115... ...
Information, education, and communication (IEC) , including social marketing and specific vitamin Aoriented nutrition education, may or may not accompany each of the above interventions.
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From page 116... ...
An extensive review of the effectiveness of strategies used to deliver nutrition educational what the nutrition science content waif 217 well-designed and carefully evaluated experiences in the United States concluded that nutrition education "works" when behavior change is the objective and the intervention is designed to achieve that goal, not just to transfer knowledge or change attitudes (Contento et al., 1996~. Market research methodology used in the private sector to achieve consumer behavior modification social behavior marketing or social mobilization is now being applied in international settings in the public sector to achieve the socially desirable, health-linked behavioral goal of improved nutritional status(Parlato, etal., 1992; Seidel, 1996~.
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From page 117... ...
are highly seasonal. Among locally available vegetables, ivy gourd (a variety of vitamin Arich DGLV)
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From page 118... ...
also showed an increased consumption of vitamin A-rich foods, including ivy gourd and fat/oil among vulnerable groups, with the exception of infants. A decreased prevalence of ocular signs of VAD (night blindness)
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From page 119... ...
. Critical elements, thought to be indispensable for replicability and sustainability for the continuation of gains beyond the project's life, were built into the program (only revisiting the project area, however, will determine if successful intervention components have been replicated in other projects and desired activities and behaviors sustained)
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From page 120... ...
Based on the lessons learned in pilot projects, Indon jesia has scaled up its social marketing strategies targeted both toward improved VAC coverage and increased consumption of vitamin A-rich foods (Straw and Green, 1996~. Internally supported national, provincial, and community mass media strategies are being implemented to broaden audience coverage.
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From page 121... ...
Applications in Brazil, India, Mauritania, and Nepal are added to some of the projects noted above. Vitamin A intervention programs carried out in this contextual diversity almost universally showed that applying a social marketing methodology in the development of nutrition education messages and other communication strategies can quite rapidly (in 18-24 months)
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From page 122... ...
An adequate water supply, however, can be a major constraint to initiating horticulture activities, render them highly seasonal, or restrict them to limited geographic areas (Brownrigg, 1985~. Until recently, few gardening projects were evaluated for biological effectiveness; of those few, changes in nutritional status were rarely demonstrated.
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From page 123... ...
In recent years, two large gardening projects have been undertaken, one sponsored through NGOs with the overall assistance of Helen Keller International (HKI) , and one project under the sponsorship of Worldview International Foundation (WIF)
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From page 124... ...
· The community participated at all levels and in all aspects of the project. · Health and nutrition education was designed for relevance to the local context and disseminated by trained local change-agents.
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From page 125... ...
It is an important demonstration that health benefits accrue from successful gardening projects that are associated with increased micronutrient-rich food consumption. Skeptics have only had information from poorly evaluated gardening projects or from controlled DGLV-feeding projects (e.g., de Pee et al., 1995)
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From page 126... ...
· A focus on women in all aspects of garden management and training in product use, including nutrition training, enhances empowerment and decisionmaking that maximize household food security and child-health benefits. · A simple information-gathering system is needed for systematic community monitoring to resolve, in a timely manner, the ongoing and evolving problems that otherwise could constrain progress and limit gardening success.
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From page 127... ...
or buriti (a traditional, beta-carotene-dense local crop in the Amazon region; see Mariath et al., 1989) to carbohydrate-rich paps and gruels can top off breast milk's vitamin A contribution toward meeting vitamin A needs in late infancy.
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From page 128... ...
Social marketing methodology to facilitate acceptance is needed to introduce nontraditional varieties with unfamiliar characteristics. Genetic engineering to enhance provitamin A activity of staple food varieties is worthy of support as a potential sustainable solution to the VAD problem among low-income populations.
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From page 129... ...
Absorption from fat-poor, postweaning diets of deprived children, however, may limit the capacity for the carotenoids from some plant sources to fully meet vitamin A needs (Jayarajan et al., 1980~. Questions were recently raised by a well-designed, controlled study of lactating Indonesian women as to whether carotenoids from DGLVs are sufficiently bioavailable to improve vitamin A status (de Pee et al., 1995~.
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From page 130... ...
The true mark of vitamin A status is total body stores. Marginally deficient Indonesian women, therefore, may have efficiently converted DGLV carotenoids and incrementally increased their total body stores, while showing only nonsignificant increments in serum and breast milk.
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From page 131... ...
Additional research in VAD-endemic areas is clearly warranted to refine our understanding of the factors associated with carotenoid bioavailability from local food sources. Precise quantitative methodologies that measure tissue stores- stable isotope dilution techniques, for example may be needed to verify bioavailability and changed vitamin A status in some of the studies.
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From page 132... ...
During this period, VAD reappeared because other VAD control interventions had not received national attention. The fortification program was reestablished around 1990, in part because of heightened global and national political and private sector awareness and sensitivity-to the consequences of the deficiency problem.
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From page 133... ...
A technical solution exists and needs to be applied: upgrading machinery to ensure uniformity in bulk-mixing of the premix containing vitamin A Indonesian Experience with Fortified Monosodium Glutamate: A National Failure Context.
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From page 134... ...
Evaluation of biological effectiveness on a national scale is riot anticipated, because this is only one of a series of national interventions to control VAD. Inferences for potential nationalimpact are made from the controlled field trial.
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From page 135... ...
Lessons learned from past failures, however, should guide national decisions to undertake fortification programs. In developing countries with rudimentary food industries, careful analysis should precede any decision to use limited public resources for fortification as opposed to other potential interventions in an "either/or" choice for VAD control.
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From page 136... ...
Lessons learned from the inappropriate use of unfortified skimmed milk to feed severely malnourished children, which precipitated xerophthalmia, were well-documented many years ago in Brazil (do Vale Pereira et al., 1966~. Additional anecdotal reports of similar experiences elsewhere stimulated WHO and the World Food Programme (FAO, 1977)
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From page 137... ...
Among infants between the ages of 9 and 12 months in India, supplement distribution is encouraged during measles immunization (India, Ministry Health and Family Welfare, 1995) , and every 6 months thereafter through feedin, and/or growth monitoring programs.
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From page 138... ...
Bangladesh has suffered from a high prevalence of xerophthalmia in preschool children, in spite of biannual distribution of high-dose supplements since 1973 (Cohen et al., 1987; Underwood, 1 990b)
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From page 139... ...
These new distribution approaches are reported to have substantially increased supplement coverage in Bangladesh (Karim et al., 1996~. Follow-up surveys will be needed to substantiate sustained high coverage and to demonstrate biological effectiveness in nationwide efforts to reduce the prevalence of VAD, a goal not achieved in over two decades of supplement distribution using other strategies.
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From page 140... ...
High-dose supplement distribution should be controlled and monitored, usually through the health infrastructure, to reduce risks of misuse (for example, to pregnant women) and multiple dosing (incidentlinked disease targeting, for example)
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From page 141... ...
PHC, including, breast-feeding promotion, immunization, growth monitoring, oral rehydration, family spacing, hygiene education, and environmental sanitation can be entry points for direct and indirect VAD control (Habte, 1987~. Disease-control programs, however, can only contribute to VAD control; increased vitamin A intake is also necessary.
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From page 142... ...
, and nutritional status generally (Mate, 1992) , argues strongly for concurrent deworming and improved vitamin A intake interventions to maximize immediate and sustained VAD control.
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From page 143... ...
COMPLEMENTARITY OF INTERVENTIONS Phasing in Vitamin A Interventions Mere VAD remains a public health problem, a mix of interventions is usually needed to meet both the acute need to treat and control health-related, and often irreversible, consequences and to sustain VAD control through affordable means (Gillespie and Mason, 1994~. In the short run, especially where xerophthalmia or severe subclinical deficiency is documented, vitamin A supplements will be part of any control strategy and may be distributed universally in time-limited distribution programs such as those discussed above.
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From page 144... ...
The examples of field experience reviewed above represent strong, arguments for formulating an overall national control strategy in which interventions overlap, each receiving the degree of emphasis appropriate for the community context and the severity of the VAD problem and a comparable share of the resources available for VAD control. The aim should be to replace universal high-dose supplement use retaining such supplements to deal with high-risk and recalcitrant situations within a time frame ranging from 2 to 5 years at a minimum; for most countries with xerophthalmia, a more realistic estimate would be up to 15-20 years (the cases in Indonesia and Tanzania, described earlier)
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From page 145... ...
(1994) reported on the costs and effectiveness of three vitamin A interventions in Guatemala: sugar fortification, capsule distribution, and gardening plus nutrition education.
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From page 146... ...
TABLE 4-6 Intervention Strategies Applicable for Prevention and Control of Iodine, Iron, and Vitamin A Deficiencies Iodine Iron Vitamin A Strategy Deficiency Deficiency Deficiency Food-based strategies Supplementationa Public health measures IEC Iodized irrigation/ drinking water? Fortification Iodized oil ++ ~ ~ +++++ Natural foods Quantitative Qualitative Fortification Iron tablets/syrup +++b Natural foods Quantitative Qualitative Fortification High-/low-dose preparations ++ aSupplements are often necessary as a time-limited measure where the problem is severe.
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From page 147... ...
Capsule distribution is a proven, timelimited, cost-effective intervention if coupled with programs that have effective service delivery to target groups and there is a consistent and adequate supply. Promotion of increased consumption and/or production of food is a viable option in most contexts where water supply is not critically short, but requires application of a social marketing methodology to overcome socioeconomic and cultural barriers to behavior changes where benefits are not always obvious.
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From page 148... ...
It is in these areas that local NGOs can make major contributions. Policy and program strategies can be set nationally, but implementation flexibility is needed to take advantage of local situations, particularly in foodbased interventions that require behavior change.
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From page 149... ...
to be of public health significance in 15 of 23 provinces. Intervention strategies were planned that included nutrition education, distribution of high-dose vitamin A supplements, food fortification, and other public health disease-control measures.
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From page 150... ...
These programs are likely to maintain national vitamin A adequacy because natural food sources are available to vulnerable populations but underutilized, and the food-processing industry is rapidly gaining, and their processed products reaching, an expanding consumer market. Success in overcoming subclinical deficiency wild require added emphasis on public health diseasecontrol interventions and poverty alleviation among hard-to-reach, high-risk households.
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From page 151... ...
Fortification, not immediately feasible as a national control program, was given exploratory emphasis for possible future inclusion in the mixture of national interventions. During the intervention phase that followed, a National Vitamin A Consultative Group (NVACG)
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From page 152... ...
Adequate vitamin A status can be achieved through food-based strategies that provide naturally occurring preformed or provitamin-A food sources and fortified food products, or vitamin A supplements. These programs often work well under controlled conditions but are less effective and sustainable when scaled up to regional or national levels.
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From page 153... ...
Bangladesh: Helen Keller International, Bangladesh. Dhaka, Bangladesh.
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From page 154... ...
1996. The effectiveness of nutrition education and implications for nutrition education policy, programs and research: a review of research.
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From page 155... ...
1995. Lack of improvement in vitamin A status with increased consumption of dark-green leafy vegetables.
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From page 156... ...
1993. An Evaluation of the Impact of Home Gardening on the Consumption of Vitamin A and Iron among Preschool Children.
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From page 157... ...
1991. Effects of deworming, dietary fat, and carotenoid rich diets Ott vitamin A status of preschool children infected with Ascaris lumbricoides in West Sumatra Province, Indonesia.
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From page 158... ...
1980. Effect of dietary fat on absorption of -carotene from green leafy vegetables in children.
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From page 159... ...
1988b. Vitamin A-fortified monosodium glutamate and health, growth, and survival of children: a controlled field trial.
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From page 160... ...
1992. Can infants and young children eat enough green leafy vegetables from a single traditional meal to meet their daily vitamin A requirements?
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From page 161... ...
1992. Participatory action for nutrition education: social marketing vitamin A-rich foods in Thailand.
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From page 162... ...
Proceedings of Ending Hidden Hunger (A policy conference on micronutrient malnutrition) , Montreal, Quebec, October 10-12, 1991, p.
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From page 163... ...
1992. Report of a Consultancy Mission to NOVIB-Sponsored Home Gardening Projects in Bangladesh.
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From page 164... ...
ACC/SCN State-of-the-Art Series, Nutrition Policy Discussion Paper No. 2, Administrative Committee on Coordination-Subcommittee on Nutrition of the United Nations, Geneva.
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From page 165... ...
1994. Improvement of night blindness situation in children through simple nutrition education intervention with the parents.
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