13 research outputs found

    Redistribution of vitamin A after iron supplementation in Indonesion infants

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    Background: Deficiencies of iron and vitamin A are prevalent worldwide. Single-micronutrient supplementation is widely used to combat these deficiencies. However, micronutrient deficiencies often occur concurrently, and there are many interactions between micronutrients. Objective: This study investigated interactions among 3 important micronutrients-iron, vitamin A, and zinc-when they are given as supplements. Design: In a randomized, double-blind, placebo-controlled supplementation trial, 387 Indonesian infants aged 4 mo were supplemented 5 d/wk for 6 mo with 10 mg Fe, 10 mg Zn, 2.4 mg beta-carotene, 10 mg each of Fe and Zn, 10 mg Zn + 2.4 mg beta-carotene, or placebo. Complete data on micronutrient status, including hemoglobin, ferritin, retinol, zinc, and the modified relative dose response (a measure of liver retinol stores), were available from 256 infants at the end of the study. Results: Iron-supplemented infants had significantly lower plasma retinol concentrations and a significantly higher prevalence of vitamin A deficiency, as defined by a plasma retinol concentration <0.70 μmol/L, than did the nonsupplemented infants. In contrast, the modified relative dose response of the iron-supplemented infants indicated greater liver stores of vitamin A. Iron supplementation improved iron status, and zinc supplementation improved zinc status, but β-carotene supplementation did not significantly improve vitamin A status. Conclusions: In this study, iron supplementation in infants with marginal vitamin A status led to lower plasma vitamin A concentrations and simultaneously to greater vitamin A liver stores. This implies a redistribution of retinol after iron supplementation, which might induce vitamin A deficiency. Therefore, iron supplementation in infants should be accompanied by measures to improve vitamin A status

    Níveis plasmáticos de vitamina A, carotenóides e proteína ligadora de retinol em crianças com infecções respiratórias agudas e doenças diarréicas Plasma levels of vitamin A, carotenoids and retinol binding protein in children with acute respiratory infections and diarrhoeal diseases

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    Planejou-se um estudo com o objetivo de se avaliar os níveis plasmáticos de vitamina A, carotenóides e proteína ligadora de retinol (RBP) em 311 crianças, de 7 meses a onze anos de idade, com história de infecções das vias aéreas superiores (IVAS), pneumonia e diarréia, residentes na área urbana da Cidade de São Paulo, Brasil, e atendidas no serviço de pediatria de um hospital-escola. As dosagens de vitamina A e carotenóides realizaram-se pelo método de Neeld-Pearson e o RBP pelo método de Mancini. Os níveis plasmáticos de vitamina A (µg/dl) e RBP (mg/dl) foram mais baixos (p<0,05) nos grupos diarréia e pneumonia (15,2 µg/dl e 1,7 µg/dl; 15,2 µg/dl; 2,6 mg/dl, respectivamente), quando comparados com os grupos IVAS e testemunha (19,0 µg/dl; 2,4µg/dl e 18,8µg/dl; 2,6mg/dl, respectivamente. Os níveis de carotenóides foram mais baixos nos três grupos de estudo em relação ao grupo testemunha (p<0,05). Os baixos níveis de vitamina A verificados nas crianças estudadas estão em concordância com outras pesquisas que encontraram diminuição dos níveis de vitamina A durante as infecções.<br>The present study was carried out in order to assess the plasma levels of vitamin A, carotenoids and retinol binding protein (RBP) of three-hundred and eleven children aged from seven months to eleven years, who had a history of upper respiratory infection (URI), pneumonia and diarrhoea. The children were resident in the urban area of the Municipality of S. Paulo, Brazil, and were seen at the pediatric service of the one school-hospital. The data show that plasma vitamin A (µg/dl) and RBP (mg/ dl) levels in the diarrhoea (15.2 µg/dl; 1.7 mg/dl) and pneumonia (15.2 µg/dl; 0.7 mg/dl) groups were lower (p<0.05) than those observed in the control (18.8 µg/dl; 2.6 mg/dl) and URI (19.0 µg/dl; 2.4 mg/dl) groups. The plasma carotenoid levels were lower in all groups than in the control group (p<0.05). These findings corroborate the results that show low levels of vitamin A in circulation during period of infection

    Lipid peroxidation and electrogenic ion transport in the jejunum of the vitamin E deficient rat.

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    Increased concentrations of reactive oxygen species in children with depleted antioxidant defences have been implicated in a cycle of malnutrition, malabsorption, and infection leading to protracted diarrhoea. A rat model of chronic vitamin E deficiency has been used to study the effects of antioxidant depletion on jejunal structure and function in vitro. Basal intestinal short circuit current (Isc), a measure of net electrogenic ion movement across the intestinal epithelium, was greater in chronically vitamin E deficient jejuna than controls, as was the electrogenic secretory response to aminophylline and Escherichia coli STa but not to bethanechol. The galactose stimulated current was also greater in vitamin E deficient jejuna. Indices of lipid peroxidation (concentrations of thiobarbituric acid reactive substances and malondialdehyde) were increased in the vitamin E deficient small bowel. Small intestinal brush border membranes from vitamin E deficient animals displayed changes in both static and dynamic components of membrane fluidity measured by steady state fluorescence polarography. The results of these studies support the hypothesis that oxidative stress in subjects with compromised antioxidant defences results in small intestinal hypersecretion, which could predispose to or perpetuate protracted diarrhoea
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