Deficiência de micronutrientes e crescimento linear: revisão sistemática de estudos observacionais / Micronutrient deficiencies and linear growth: a systematic review of observational studies

O objetivo do artigo é avaliar a associação das deficiências de ferro, vitamina A e zinco com o déficit de crescimento linear. Revisão sistemática nas bases de dados eletrônicas PubMed, LILACS e SciELO. Foram selecionados artigos publicados entre janeiro de 1995 e março de 2010, considerando os descritores: (growth OR nutritional status) AND (child, preschool OR infant) AND (zinc AND iron AND vitamin A) OR (zinc AND iron) OR (zinc AND vitamin A) OR (iron AND vitamin A). Foram revisados 14 estudos de delineamento observacional. Dos estudos tipo coorte (dois), um indicou associação estatística entre o estado nutricional de ferro e o déficit de estatura; o outro apontou associação estatística entre as concentrações de ferritina sérica e o ganho de estatura. Dez estudos transversais investigaram a associação estatística entre as deficiências de micronutrientes e o déficit de estatura, resultando três deles na associação para o ferro, dois para a vitamina A e nenhum para o zinco. O esclarecimento sobre a associação entre o déficit de estatura e as deficiências de ferro, vitamina A e zinco dificulta-se por fatores de caráter biológico e relacionados à magnitude das deficiências, o que sugere a importância da padronização metodológica dos estudos.

This article seeks to evaluate the association of iron, vitamin A and zinc deficiencies with linear growth retardation. A systematic review of electronic databases in PubMed, LILACS and SciELO was conducted. Scientific papers published between January 1995 and March 2010 were selected, inserting the key words: (growth OR nutritional status) AND (child, preschool OR infant) AND (zinc AND iron AND vitamin A) OR (zinc AND iron) OR (zinc AND vitamin A) OR (iron AND vitamin A). Fourteen observational design studies were reviewed. In the cohort studies (two), one indicated a statistical association between iron levels and stunting; and the other revealed a statistical association between serum ferritin concentrations and an increase in height. Ten cross-sectional studies investigated the statistical association between micronutrient deficiencies and stunting, three of which resulted in an association with iron, two with vitamin A and none with zinc. Elucidation of the association between stunting and iron, vitamin A and zinc deficiencies involves difficulties of a biological nature and also related to the magnitude of these deficiencies, indicating the importance of a methodological standardization of the studies.

Crescimento e deficiências de micronutrientes: perfil das crianças assistidas no núcleo de creches do governo da Paraíba, Brasil / Growth and micronutrient deficiencies: profile of children attendied at the day care center for the government of Paraiba, Brazil

O objetivo deste artigo é avaliar o perfil de crescimento das crianças assistidas no Núcleo de Creches do Governo da Paraíba e a contribuição relativa das deficiências de vitamina A, ferro e zinco. Estudo transversal em 240 crianças pré-escolares. Foram consideradas as categorias de diagnóstico nutricional: déficit ponderal, déficit de estatura e sobrepeso. As concentrações séricas de retinol, zinco e de hemoglobina foram determinadas para avaliar a deficiência de vitamina A (< 0,70 µmol/L), deficiência de zinco (< 65 Μmol/L) e anemia (< 110 g/L), respectivamente. A prevalência de déficit de estatura foi de 5,8%, a de sobrepeso de 3,8%, e a de déficit de peso de 0,4%. A média de Escore-Z para o índice P/E foi menor e estatisticamente significante quando a mãe da criança foi diagnosticada com baixa estatura ou com baixo peso e nas crianças de 12-36 meses de idade. Para o índice E/I, a média de Escore-Z foi menor e estatisticamente significante quando a criança nasceu com baixo peso e quando a mãe da criança apresentou baixa estatura. Crianças de 12-36 meses e sem o beneficio do Programa Bolsa Família tiveram média de hemoglobina menor. Verificou-se ausência de associação significante entre as deficiências de vitamina A, ferro e zinco e os índices antropométricos estudados.

This article seeks to evaluate the growth of children attending public day care centers of the Government of the State of Paraiba and the relative significance of vitamin A, iron and zinc deficiencies. It involved a cross-sectional study of 240 preschool children. The following categories of nutritional status were considered: underweight (W/H < -2 z-scores), stunting (H/A < -2 z-scores) and overweight (W/H > +2 z-scores). Serum concentrations of retinol, zinc and hemoglobin were established to assess vitamin A deficiency (< 0.70 mmol/L), zinc deficiency (< 65 mmol/L) and anemia (< 110 g/L), respectively. The prevalence of stunting was 5.8%, that of overweight 3.8%, and that of underweight 0.4%. W/H z-scores were lower and statistically significant in children aged 12-36 months. An association was also found between W/H z-scores and maternal height. This association was also observed regarding body mass index. H/A z-scores were lower and statistically significant in low birth weight children. Lower hemoglobin concentrations were detected in children aged 12-36 months who were not receiving the financial support of the Bolsa Familia (Family Allowance) program. There was no significant association between vitamin A, iron and zinc deficiencies and the anthropometric indices studied.

Influence of dietary vitamin A deficiency on rat digestive & absorptive functions during diabetes mellitus.

Intestinal absorption of glucose and activities of amylases of intestinal and pancreatic origin were measured in animals vitamin A deficient, diabetic and combined state of vitamin A deficiency with diabetes. The vitamin A deficient diet caused a significant reduction in intestinal digestive and absorptive functions. On the other hand the digestive and absorptive functions were increased in the diabetic state. The combination of diabetes with vitamin A deficient diet caused a decrease in the digestive and absorptive functions along with blood glucose level in comparison to diabetic state alone. These findings suggest that the inhibition of digestive and absorptive functions observed in the combined state of vitamin A deficiency and diabetes may be due to the presence of vitamin A deficient diet.

Influence of combined deficiency of fat and vitamin A on benzo(a)pyrene-induced lung carcinogenesis in rats.

The present study shows the effect of combined dietary deprivation of fat and vitamin A on benzo(a)pyrene (BaP) induced lung carcinogenesis in male Wistar rats. Lung tumors were induced by intratracheal instillation of BaP-Fe2O3 in normal saline. The tumor incidence and tumor burden in control animals were 82% and 2.28 respectively. Fat deficiency decreased the tumor incidence to 57% and tumor burden to 1.66. On the other hand, in vitamin A deficiency these were 83% and 4.02 respectively. Fat deprivation in the diet of animals fed with vitamin A deficient diet decreased the tumor incidence and tumor burden to 69.6% and 2.7 respectively. The results suggest a protective role of low intake of fat in vitamin A deficiency for BaP-induced lung tumorigenesis in rats.

Effect of vitamin A deficiency on rat intestinal digestive & absorptive functions.

The effect of vitamin A deficiency on the intestinal absorption of nutrients and the activities of brush border enzymes were studied in albino rats. Intestinal uptakes of D-glucose, L-methionine, L-tryptophan and L-histidine were significantly greater in vitamin A-deficient animals than in controls. The specific activities of total adenosine triphosphatase (ATPase), ouabain-sensitive ATPase, maltase and sucrase in the intestinal mucosa of vitamin A-deprived rats were 121, 124, 131 and 134 per cent respectively, of the corresponding values in control animals. The DNA content of the small intestine in vitamin A-deficient rats was 36.5 per cent lower than in control rats. The stimulation in digestive and absorptive capacity appears to be an adaptive change in vitamin A-deficiency which decreases the intestinal cell population.