[Vitamin A deficiency in Brazil: an overview]

Prolonged vitamin A deficiency may cause a severe disorder, hypovitaminosis A, that in turn may result in xerophthalmia and blindness. Although preventable, hypovitaminosis A is still a public health problem in many developing countries. This article presents an overview of the information available about vitamin A deficiency in the world and especially in Brazil. The piece also discusses the social impact of hypovitaminosis A, which is an important determinant of morbidity and mortality among children, and the relevance of prevention in the fight against this disorder. Although some studies have been done in Brazil, the information concerning vitamin A deficiency is not sufficient to determine the magnitude and severity of hypovitaminosis A on a national level, especially due to the small size of the samples studied and to the dearth of clinical and biochemical studies, which often present contradictory results. Nevertheless, it is clear that the intake of vitamin A is below recommended levels among the poor and that most children do not consume the amount recommended by the World Health Organization. In part, this could be remedied by educating people on foods that are rich in vitamin A and by correcting their attitudes toward certain dietary taboos. As part of this effort, schools play a major role in the prevention of vitamin A deficiency, among both students and the broader community.

[Pre-cooked corn flour intake and its contribution of iron and vitamin A in low income preschoolers]

The objective of this study was to determine whether the addition of iron and vitamin A (VA) to corn flour, supplied through a national enrichment program since 1993, allows preschoolers to achieve an adequate intake of these nutrients. Data from the assessment of 196 children (4-6 year old) from Valencia, Venezuela is presented, including socio-demographic, anthropometric, anemia, VA deficiency (by conjunctival impression cytology (CIC) and serum retinol), and food intake. 92% of the children lived in poverty. 12% were below the norm for weight-for-height. 13% had anemia, 9% had VA deficiency according to CIC, and 0.5% according to serum retinol (< 0.70 mumol/L), 30% were at risk of VA deficiency (0.70-1.05 mmol/L). 17%, 37%, and 5% of the sample had an insufficient intake (< 80% of RDA) of energy, iron, and VA, respectively. When excluding from the analysis the amount of iron and VA from corn flour enrichment, an additional 38% and 10% of the sample showed deficient intakes of each nutrient, respectively. According to the weight-for-height indicator, iron intake was significantly lower in undernourished children (p < 0.05) than in those normal or above the norm; this was not so for VA. It is concluded that iron enrichment contributes to the improvement of the intake of this nutrient but is not enough to provide an adequate amount of it; and that the addition of VA does not seem to have an important effect on the diet of this age group.

Use of under-five mortality rate as an indicator for vitamin A deficiency in a population

Vitamin A deficiency (VAD) is an important problem in many developing countries. If population data are unavailable or outdated for common indicators of VAD, a surrogate indicator may suggest whether a problem is likely and full-scale assessment is necessary. The Global Vitamin A Initiative report suggests that the under-five mortality rate (U5MR) might serve that purpose; a U5MR >70 indicates that VAD of public health importance is likely. Should the U5MR be used as a surrogate indicator? If so, is 70 the appropriate cutoff? U5MR data were collected for countries where the United Nations Children's Fund supports programs, along with unpublished vitamin A survey data from the World Health Organization. U5MR distribution was compared in countries with and without VAD. Sensitivity and specificity using U5MR cutoffs of 70 and 50 were calculated and compared with the presence of VAD as proven by a survey. Countries with a U5MR >40 have a VAD problem, about 70% of countries with a U5MR between 20 and 50 have VAD, and about 25% of countries with a rate <20 still have VAD. With a cutoff of 50, the U5MR relates well to the existence of a VAD problem in regions where malnutrition problems are most prominent. Decreasing the cutoff from 70 to 50 increased the sensitivity of the criterion and included nine additional deficient countries. A cutoff of 40 would increase sensitivity but would include countries with localized rather than nationwide problems. It is proposed that a country with a U5MR >50 likely has a VAD problem that requires immediate or continuing action. These actions include proper, formal assessment of the vitamin A status of the population, vitamin A capsule distribution and other program actions. Countries with a U5MR between 20 and 50 should assume they have a VAD public health problem until surveys prove otherwise.

Vitamin A during pregnancy

Vitamin A is an essential micronutrient throughout life. In areas of developing countries where vitamin A deficiency is endemic, an estimated 40% of the children are likely to be sub clinically deficient of the vitamin. Yet, the traditional view that preschool age children represent the main population at risk of vitamin A deficiency has been replaced by the growing awareness that sub clinical and even clinical vitamin A deficiency also occurs in women of reproductive age and infants less than 6 month of age. During the period of early foetal development the supply of vitamin A must be carefully managed to ensure that the developing foetus is exposed to neither too little not too much vitamin A because either condition can have teratogenic consequences. Towards the end of gestation, adequate maternal vitamin A status and dietary intakes are important to maximize the vitamin A transferred to the foetus in preparation for parturition and lactation. A review of the current knowledge and prospects for future research is presented.

Mass supplementation of vitamin A linked to National Immunization Day

OBJECTIVE

Main objectives were to assess the feasibility of linking vitamin A delivery with National Immunization Days (NIDs) and to see the impact on xerophthalmia.

METHODS

An Intervention study of mass distribution of vitamin A solution was undertaken to control widespread xerophthalmia prevalent in children living in about 26 slums of Chandigarh in the year 2000. Two rounds of mass distribution of Vitamin A solution covering 27642 and 31762 children in 1-5 years of age in first and second rounds, respectively, were undertaken. The findings of second round and post evaluation after intervention are presented here. An additional team of two persons per pulse polio immunization (PPI) centre delivered age specific doses of vitamin A solution through 98 centres and operational problems were recorded. PPI staff provided the supervision and PPI tally sheets were used.

RESULTS

The programme achieved a vitamin A coverage rate of 99% in first round and 88% in second round. Only two parents refused vitamin A solution. No side effect or cases of toxicity due to vitamin A were reported by health institutions in the area or in a stratified random sample of 101 children. There was a significant decline (13.4%) in xerophthalmia after two rounds of mass distribution (P < .001). The strategy to deliver vitamin A was successfully integrated into NID's and appeared to achieve a significant decline in xerophthalmia.

CONCLUSION

Linking of vitamin A distribution with PPI could be a basis for launching similar initiatives in other areas of India and other countries where xerophthalmia is a public health problem.

Xerophthalmia among hospitalized Iraqi children

To determine the impact of sanctions on the nutritional status of Iraqi children aged < 6 years, a random sample of 700 patients (age range: 0-6 years) from the Saddam Paediatric Hospital, Diyala Province, Iraq were examined ophthalmologically for evidence of xerophthalmia. Data on the history of infection, feeding and night blindness were also collected. The prevalence of xerophthalmia was 29%, mostly among children aged 1-3 years. Xerophthalmia was significantly inversely associated with breastfeeding and highly associated with common childhood infections such as measles, diarrhoea and respiratory tract infection. Xerophthalmia is a common problem among sick Iraqi children. Efforts to identify, evaluate and monitor vitamin A deficiency and to advocate and plan its eradication should be implemented.

Prevalence of micronutrient malnutrition worldwide

Recent estimates indicate that globally over two billion people are at risk for vitamin A, iodine, and/or iron deficiency, in spite of recent efforts in the prevention and control of these deficiencies. The prevalence is especially high in Southeast Asia and sub-Saharan Africa, and pregnant women and young children are at greatest risk. Other micronutrient deficiencies of public health concern include zinc, folate, and the B vitamins. However, there is limited data on the actual prevalence of these deficiencies. Finally, in many settings, more than one micronutrient deficiency exists, suggesting the need for simple approaches that evaluate and address multiple micronutrient malnutrition.

Control of micronutrient deficiencies in India: obstacles and strategies

Micronutrient deficiencies of vitamin A, iron, and iodine continue to be of public health significance in India. The government of India initiated national programs to prevent, control and combat these deficiencies and their serious consequences. The interventions involved (1) distribution of iodized salt in the endemic areas, (2) administration of semiannual massive dose of vitamin A to young children, and (3) distribution of iron-folic acid tablets to the vulnerable groups. Evaluations revealed that the biologic impact of these interventions was unsatisfactory. Inadequate allocation of funds (10% of the actual needs) necessary to cover the enormous number of beneficiaries was one of the important obstacles. Consequently, the allocation of supplies to different provinces was far short of the requirements (10-30%). As a result of poor orientation, the functionaries were not adhering to the guidelines, leading to woefully inadequate (1-20%) and irregular coverage. There was no proper monitoring or supervision to make midcourse corrections to improve the functioning. The community was not informed of the purpose and details of each intervention. Hence, it did not utilize the resources completely and remained passive recipients. The community was not aware of the dietary approaches to prevent micronutrient disorders owing to absence of nutrition education. With the adoption of National Nutrition Policy by the government of India, a concerted and focused approach should be adopted. The future strategies should include a mix of short-term supplementation and food-based strategy encompassing food fortification and home gardening. Innovative approaches in information, education, and communication (such as social marketing strategy) for making the interventions sustainable should be adopted.

Can supplements help meet the micronutrient needs of the developing world?

Supplementation has many potential advantages over fortification and dietary approaches for improving micronutrient intake. Pregnant and lactating women and infants are most likely to benefit from supplementation. Recent experience with vitamin A supplementation in young children has proved to be remarkably successful. Demonstrated efficacy of vitamin A supplements for improved child survival in many settings and a technical consensus on how to implement interventions were major factors in achieving this success. Bilateral and UN agencies worked together so that in 1999 80 % of children under 5 years of age in the least-developed countries received a vitamin A capsule in the last 6 months. At least one million child lives saved were associated with the increase in coverage in the last 2 years of the 1990s. Experience with Fe-folate supplements has not been as successful. Whilst a technical consensus has been reached on how to implement programmes to control Fe deficiency, the lack of convincing evidence of efficacy of Fe-folate supplements in terms of maternal and child survival outcomes has undoubtedly contributed to the limited pursuit of effective action. A new multiple micronutrient supplement for use amongst women of reproductive age in developing countries has been formulated. UNICEF is employing the supplement in programmes aimed at helping to prevent low birth weight. The new supplement is likely to be more efficacious than Fe-folate supplements for both maternal and child survival and development outcomes. Successful completion of rigorous efficacy trials will be critical for creating the political support needed to achieve universal coverage.

Sugar as a potential vehicle for vitamin A fortification: experience from Kamuli district in Uganda

BACKGROUND

Despite measures put in place by the Uganda Government ten years ago to combat Vitamin A deficiency, the number of children suffering from this deficiency remains high.

OBJECTIVE

To determine whether sugar may be used as a vehicle for vitamin A fortification.

DESIGN

Cross-sectional descriptive study.

SETTING

Kamuli district in Uganda.

PATIENTS

One thousand one hundred and four children, and one thousand one hundred and two mothers or care-takers participated in the study. Sugar consumption patterns for the two age groups were determined. The methods of sugar storage in households were also determined. The children were aged 12 to 36 months, and mothers/caretakers 16 to 45 years.

RESULTS

The overall proportion of households where sugar was consumed in the last seven days was 89.2% for children, and 88.3% for mothers/caretakers. Sugar was stored in covered tins in 67% of the households, and in covered baskets in 28% of households.

CONCLUSION

Sugar is a potential vehicle for fortification with vitamin A for Kamuli district. Storage of sugar in covered tins and baskets means that the stability of the vitamin A in the fortified sugar might not be affected by exposure to light.

Effect of vitamin A administered at Expanded Program on Immunization contacts on antibody response to oral polio vaccine

OBJECTIVE

Vitamin A supplementation to mothers in the postpartum period and to their infants at routine immunization contacts is being considered to reduce vitamin A deficiency in infancy. This study was conducted to determine the impact of maternal and infant vitamin A supplementation on antibody response to oral polio vaccine (OPV).

DESIGN

Randomized, double blind, placebo-controlled trial.

INTERVENTIONS

Mothers in the intervention group received 60 mg retinol equivalent (RE) vitamin A 3-4 weeks after delivery and their infants 7.5 mg RE with each OPV dose at 6, 10 and 14 weeks of age. The control group mothers and their infants received a placebo at each of these contacts.

MAIN OUTCOMES

Geometric mean (GM) titer of neutralizing antibodies and proportion of children with protective titer to the three polioviruses at 26 weeks of age.

RESULTS

Vitamin A supplementation increased the proportion of infants with protective antibody titer against poliovirus type 1 (relative risk (RR) 1.15, 95% confidence interval (CI) 1.03-1.28) and the GM antibody titer (ratio of GM 1.55, 95% CI 1.03-2.31) following immunization. The proportion of infants with protective antibody titer against poliovirus type 2 (RR 0.99, 95% CI 0.94-1.05) or type 3 (RR 1.05, 95% CI 0.96-1.15) was not significantly different in vitamin A and placebo groups. The GM antibody titer for poliovirus type 2 (ratio of GM 0.99, 95% CI 0.64-1.54) or poliovirus type 3 (ratio of GM 1.10, 95% CI 0.69-1.75) also did not differ across groups.

CONCLUSIONS

Vitamin A given to the mothers in the postpartum period and their infants with OPV did not interfere with the antibody response to any of the three polioviruses and enhanced the response to poliovirus type 1.

Improving iron, zinc and vitamin A nutrition through plant biotechnology

Recent understanding of plant metabolism has made it possible to increase the iron, zinc and beta-carotene (provitamin A) content in staple foods by both conventional plant breeding and genetic engineering. Improving the micronutrient composition of plant foods may become a sustainable strategy to combat deficiencies in human populations, replacing or complementing other strategies such as food fortification or nutrient supplementation.

Golden Rice: introducing the beta-carotene biosynthesis pathway into rice endosperm by genetic engineering to defeat vitamin A deficiency

To obtain a functioning provitamin A (beta-carotene) biosynthetic pathway in rice endosperm, we introduced in a single, combined transformation effort the cDNA coding for phytoene synthase (psy) and lycopene beta-cyclase (beta-lcy) both from Narcissus pseudonarcissus and both under the control of the endosperm-specific glutelin promoter together with a bacterial phytoene desaturase (crtI, from Erwinia uredovora under constitutive 35S promoter control). This combination covers the requirements for beta-carotene synthesis and, as hoped, yellow beta-carotene-bearing rice endosperm was obtained in the T(0)-generation. Additional experiments revealed that the presence of beta-lcy was not necessary, because psy and crtI alone were able to drive beta-carotene synthesis as well as the formation of further downstream xanthophylls. Plausible explanations for this finding are that these downstream enzymes are constitutively expressed in rice endosperm or are induced by the transformation, e.g., by enzymatically formed products. Results using N. pseudonarcissus as a model system led to the development of a hypothesis, our present working model, that trans-lycopene or a trans-lycopene derivative acts as an inductor in a kind of feedback mechanism stimulating endogenous carotenogenic genes. Various institutional arrangements for disseminating Golden Rice to research institutes in developing countries also are discussed.

Development and validation of a short food-frequency questionnaire for screening women of childbearing age for vitamin A status in northwestern Iran

A high percentage of women in their childbearing years suffer from subclinical vitamin A deficiency; 10% to 20% of pregnant women worldwide are vitamin A deficient. This study aimed to design and validate a short food-frequency questionnaire to serve as a simple screening tool for vitamin A status in women of childbearing age. The sample consisted of 187 healthy, nonpregnant, nonlactating women 15 to 49 years of age, from urban and rural areas of Marand district in East Azerbaijan. Dietary intake was evaluated by a face-to-face interview using a 24-hour dietary recall for two consecutive days and a 41-item qualitative food frequency questionnaire. Height, weight, and serum retinol were measured. Serum retinol values were less than 20 micrograms/dl for three subjects, while an additional 34 subjects (18%) had values between 21 and 30 micrograms/dl. Principal-component analysis performed on the food-frequency questionnaire identified five components that together defined 34.4% of the variance in estimated vitamin A intake and were used to derive a 20-item short food-frequency questionnaire. Internal consistency of the short instrument was acceptable (Cronbach's alpha = .59). Serum retinol was significantly correlated with total vitamin A intake and with intake of vitamin A from plant sources, as estimated by the short food-frequency questionnaire. Important sources of provitamin A in these women's diets included some not typical of other populations: nuts and green leaves of types used elsewhere in small quantities as herbs, but important in Iran because the amount and frequency of consumption are relatively high. We conclude that the questionnaire is relatively valid and potentially useful in identifying women at risk for vitamin A deficiency in this population.

Impact of vitamin A supplementation through different dosages of red palm oil and retinol palmitate on preschool children

Red palm oil (5 ml and 10 ml), ground nut oil fortified with 400 and 800 retinol equivalent retinol palmitate, and ground nut oil (5 and 10 ml), were administered to six groups of preschool children (four experimental and two control groups) in randomly assigned balwadis of Ramanathapuram District of Tamil Nadu for a period of 7 months, to monitor the difference in the efficacy of the mode of supplementation and the optimum dose for improving vitamin A status. Results show that red palm oil groups recorded more gain in retinol and beta-carotene levels compared to other dosage groups, and that administration of 10 ml did not offer any substantial improvement over the 5-ml daily dose.

Vitamin A deficiency in Nigeria

Childhood blindness is second only to cataract in magnitude of world blindness when the "blind years" is considered. The "blind years" is the number of years a person lives with blindness. Studies have shown that over 34%-69% of childhood blindness in Nigeria is caused by corneal opacity, which results mainly from an interplay of vitamin A deficiency, measles and harmful traditional eye practices. However, vitamin A deficiency which manifests in the eye as xerophthalmia is the dominant problem in these children. The purpose of this review is to stress the importance of xerophthalmia, which is of public health significance, as an important cause of childhood blindness in Nigeria. Studies involving surveys of xerophthalmia, childhood and nutritional blindness are reviewed with data extracted from a nationwide survey on prevalence of xerophthalmia. The likely explanation for vitamin A deficiency in Nigerian children is discussed with possible solutions and recommendations made to control this avoidable and devastating cause of blindness.

Impact of targeted programs on health systems: a case study of the polio eradication initiative

The results of 2 large field studies on the impact of the polio eradication initiative on health systems and 3 supplementary reports were presented at a December 1999 meeting convened by the World Health Organization. All of these studies concluded that positive synergies exist between polio eradication and health systems but that these synergies have not been vigorously exploited. The eradication of polio has probably improved health systems worldwide by broadening distribution of vitamin A supplements, improving cooperation among enterovirus laboratories, and facilitating linkages between health workers and their communities. The results of these studies also show that eliminating polio did not cause a diminution of funding for immunization against other illnesses. Relatively little is known about the opportunity costs of polio eradication. Improved planning in disease eradication initiatives can minimize disruptions in the delivery of other services. Future initiatives should include indicators and baseline data for monitoring effects on health systems development.

Vitamin A and iron supplementation of Indonesian pregnant women benefits vitamin A status of their infants

Many Indonesian infants have an inadequate nutritional status, which may be due in part to inadequate maternal nutrition during pregnancy. This study was designed to investigate whether infant nutritional status could be improved by maternal vitamin A and Fe supplementation during gestation. Mothers of these infants from five villages had been randomly assigned on an individual basis, supervised and double-blind, to receive supplementation once weekly from approximately 18 weeks of pregnancy until delivery. Supplementation comprised 120 mg Fe and 500 microg folic acid with or without 4800 retinol equivalent vitamin A. Mothers of infants from four other villages who participated in the national Fe and folic acid supplementation programme were also recruited; intake of tablets was not supervised. Anthropometric and biochemical parameters of infants and their mothers were assessed approximately 4 months after delivery. Infants of mothers supplemented with vitamin A plus Fe had higher serum retinol concentrations than infants of mothers supplemented with Fe alone. However, the proportion of infants with serum retinol concentrations <0.70 micromol/l was >70 % in all groups. Maternal and infant serum retinol concentrations were correlated. Fe status, weight and length of infants were similar in all groups. Fe status of girls was better than that of boys, but boys were heavier and longer. We conclude that supplementation with vitamin A in conjunction with Fe supplementation of women during pregnancy benefits vitamin A status of their infants. However, considering the large proportion of infants with marginal serum retinol concentrations, it may still be necessary to increase their vitamin A intake.

Risk of inadequate intakes of vitamins A, B1, B6, C, E, folate, iron and calcium in the Spanish population aged 4 to 18

A meta-analysis of the most representative Spanish nutrition studies was carried out to identify inadequate intakes of vitamins, A, B1, B6, C, E, folate, iron, and calcium in children aged 4 to 18. Information on vegetable, fruit and fruit juice/beverage intake was also solicited. Data drawn from the selected studies yielded a total of 6540 children and adolescents in eight geographical areas. The sample was stratified by age (children: 4 to 14 years old and adolescents: 13-18 years old) and sex. Inadequate intakes (below two-thirds of the recommended values) were notable in children for vitamin E, vitamin C, and vitamin A and in girls, iron. In adolescents, low intakes were especially marked for vitamin E and vitamin A, and in girls, calcium, folate, and iron. Adolescents consumed more vegetables, fruit juice, and fruit drinks whereas children had higher fruit intakes. Regional differences in consumption were also detected. Strategies for improving nutrient intake in these vulnerable populations are discussed.

Relationship between plasma retinol and infectious diseases in the elderly. A case-control study

This study assessed the relationship between plasma retinol deficiency and infectious diseases. The plasma retinol, anthropometric (Body Mass Index, triceps skinfold thickness, mid-arm muscle circumference) and biological indices (proteins, albumin, transferrin, prealbumin, retinol binding protein) of protein-energy malnutrition of 63 patients with infectious diseases (ID) were compared to those of two control groups of similar age: 527 patients with other diseases (C1) and 92 healthy people (C2). Plasma retinol, albumin, transferrin and prealbumin were significantly lower in the ID group than in the C1 group. A lower body mass index was noted in men only. The ID and C1 groups had lower values for all indices (except for mid-arm muscle circumference). The ID group had lower albumin, transferrin, and prealbumin than the C1 group. The percentage of patients with plasma retinol below 300 microg/l was higher in the ID group (48.0% in men, 39% in women) than in the C1 group (25.0 and 21.5%); the odds ratio adjusted on age and sex equaled 2.46, 95% CI (1.39-4.37). It was lower than 2% in the C2 group. The results obtained with multiple regression analysis showed that, in the patients, the association between plasma retinol and infectious diseases remained significant when age, sex, anthropometric and biological indices were taken into account. Consequently, it is useful to check up the food intake habits of the elderly.