Effect of iron supplementation on physical performance in children and adolescents: systematic review of randomized controlled trials.

OBJECTIVE: To evaluate the effect of iron supplementation on physical performance in children (0-18 years) through systematic review of randomised controlled trials (RCTs). DATA SOURCES: Electronic databases, personal files, handsearch of reviews, bibliographies of books, abstracts and proceedings of international conferences. REVIEW METHODS: RCTs with interventions that included oral or parenteral iron supplementation, fortified formula milk, or cereals were evaluated. The physical performance outcomes studied were heart rate, treadmill endurance times, blood lactate, and oxygen consumption. RESULTS: A total of three studies were included, in all of which iron was supplemented in the form of oral medicinal iron. At 5, 6 and 7 miles per hour running speeds, the pooled weighted mean (95% Cl) difference (WMD) in the heart rate (per minute) between the iron and the placebo, following exercise was -7.3 (-19.6, 4.9; p = 0.241), -6.6 (- 19.9, 6.6; p = 0.327), and -8.0 (-19.7, 3.7; p = 0.182), respectively. After excluding the study with nonanemic subjects, the corresponding figures were -13.1 (-23.2, -3.1; p= 0.01), -14.2 (-22.3, -6.1; p = 0.001) and -12.7 (-23.5, 1.9; p = 0.021), respectively. Oxygen consumption, estimated in two studies, showed no significant difference between the treatment groups. Blood lactate levels were estimated in one study only at two different doses of iron, and were significantly lower (p < 0.05) in iron supplemented group in comparison to placebo both before (7.71 and 7.55 mg/dL versus 8.43 mg/dL) and after (14.36 and 14.35 mg/dL versus 16.48 mg/dL) exercise. Treadmill endurance time was significantly better in iron supplemented group when compared with placebo in one study. CONCLUSIONS: Iron supplementation may have a positive effect on the physical performance of children, as evaluated through the post exercise heart rate in anemic subjects, blood lactate levels and treadmill endurance time. In view of the limited data availability, this finding cannot be considered conclusive.

Undernutrition among Honduran children 12-71 months old

In 1996, the Ministry of Health of Honduras conducted a national micronutrient survey that included anthropometric measurements to determine the nutrition status of children 12-71 months old. Among the 1.744 children who participated, 38 percent of them were stunted, including 14 percent who were severely stunted; 24 percent were underweight, of which 4 percent were severely underweight; and 1 percent were wasted, of which 0,1 percent were severely wasted. The country can be divided into three groupings based on the level of stunting and underweight: 1) lowest prevalence: Tegucigalpa, San Pedro Sula, and medium cities; 2) medium prevalence: other urban areas, the rural north, and the rural south; and 3) highest prevalence: the rural west. Using logistic regression analysis, the important determinants of stunting were found to be: mother/caretaker's and father's schooling, source of water, the dominion (geographic location and strata) in which the child lived, and the "possession score" for ownership of such items as a radio, television, refrigerator, stereo system, and electric iron. The predictors for underweight were micronutrient status, diarrhea, maternal/caretaker's schooling, type of toilet, and possession score. Historical data indicate that the national prevalence of chronic undernutrition has changed little over the last 10 years despite the number of national food and nutrition plans implemented and the significant improvements in health services. It is possible that these positive interventions have been offset by the slow progress in economic development. Future nutrition interventions should take into account household-level perceived needs and priorities in order to set realistic nutrition targets

The role provitamin A carotenoids in the prevention and control of vitamin A deficiency

El hecho de que el ß-caroteno es la fuente principal de la vitamina A en frutas y vegetales ha sido conocido por muchos años. Varios estudios han sido conducidos para evaluar la bioconversión del ß-caroteno en vitamina A en animales. Más recientemente, estudios de bioconversión con ß-caroteno marcado con isótopos estables han sido utilizados para evaluar la bioconversión en humanos. La eficiencia de la conversión de ß-caroteno en vitamina A aceptada es seis, sin embargo este valor puede variar dependiendo del status en vitamina A. Este articulo discute los estudios en humanos con suplementos de ß-caroteno puro o consumo de frutas y verduras, efectuados para averiguar si el ß-caroteno puede alterar el estado de vitamina A de poblaciones deficientes. La conclusión es que faltan datos de estudios bien diseñados para mostrar que, con la posible excepción del aceite de palma roja. Los alimentos ricos en ß-caroteno son tan efectivos como los suplementos de vitamina A en la eliminación de la deficiencia de vitamina A. Sin embargo, los datos muestran que alimentos ricos en carotenoides pueden ser importantes para la prevención de la deficiencia de vitamina A

Vitamin A deficiency and anemia among children 12-71 months old in Honduras

Vitamin A deficiency (VAD) and iron deficiency anemia (IDA) have been recognized as public health problems in Honduras for over 30 years. This paper, based on the 1996 National Micronutrient Survey on 1.678 children 12-71 months of age, presents the results for vitamin A status and anemia prevalence, as well as the level of vitamin A in sugar at the household level. The results showed that 14 per cent of the children were subclinically vitamin A deficient (plasma retinol < 20 ug/dL) and 32 per cent were at risk of VAD (plasma retinol 20-30 ug/dL). These data indicate that VAD is a moderate public health problem in Honduras. Logistic regression analysis showed that children 12-23 monts old living in areas other than the rural south of the country were at greatest risk of subclinical VAD. Infection, indicated by an elevated alpha-1-acid-glycoprotein level, increased the risk of subclinical VAD more than three-fold. Children from households that obtained water from a river, stream, or lake were at twice the risk of subclinical VAD compared with other children. That same doubled risk was found for children from a household with an outside toilet. VAD can be controlled by fortifying sugar. Retinol levels in sugar at the household level were about 50 per cent of those mandated by Honduran law. There appears to be significant leakage of unfortified sugar into the market. This is particularly true in the rural north, where 33 per cent of samples contained no retinol. Overall, 30 per cent of children were anemic (Hb < 11 g/dL). Logistic regression analysis showed that children whose fathers lived with them but who had not attended at least grade 4 of primary school were at 33 per cent greater risk of being anemic. Infection and being underweight increased the risk of being anemic by 51 per cent and 21 per cent, respectively. Many of the anemic children had not been given iron supplements, suggesting health care providers may not be aware that anemia is widespread among young children and/or know how to diagnose it

Nutrition of Honduran mothers/caretakers

In 1996, the Honduran Ministry of Health conducted a national micronutrient survey of children 12-71 months old, which also included an assessment of the nutrition status of their mothers/caretakers. The 1.126 mothers/caretakers who participated in the survey tended to be short and plump. About 15 per cent of them were at obstetric risk by virtue of their short stature and/or low body weight. About 9 per cent had chronic energy deficiency (CED), but 27 per cent were at least 20 per cent overweight. CED was associated with socioeconomic indicators of poverty. Risk factors for being at least 20 per cent overweight included being over 30 years old, not breast-feeding, having attended no higher than grade 4, 5, or 6 of primary school, coming from a wealthier household, and living in San Pedro Sula or medium-sized cities. Among the women surveyed, 26 per cent of nonpregnant and 32 per cent of pregnant mothers/caretakers were anemic. The likely principal cause of anemia was the low intake of bioavailable iron from food and, in some cases, excessive iron loss associated with intestinal parasites, especially hookworm. Only 50 per cent of the mothers/caretakers participating in this study had received iron during their las pregnancy, and just 13 per cent had received post-partum vitamin A. The results highlight the need to develop and implement an effective program to control iron deficiency anemia in women of reproductive age, including by fortifying such widely consumed foods as processed wheat and maize flour and by routinely administering iron supplements to high-risk groups. Postpartum vitamin A supplementation should be encouraged to protect both the mother and newborn infant against vitamin A deficiency