Revista Brasileira de Ginecologia e Obstetrícia (Aug 2012)
Níveis de alfa-tocoferol no soro e colostro de lactantes e associação com variáveis maternas Alpha-tocopherol level in serum and colostrum of breastfeeding women and association with maternal variables
Abstract
OBJETIVOS: Diagnosticar bioquimicamente o estado nutricional de vitamina E de lactantes por meio da análise do alfa-tocoferol no soro e no colostro, verificar sua associação com variáveis maternas e determinar a prevalência de deficiência de vitamina E nessas mulheres. MÉTODOS: Participaram do estudo 103 puérperas que foram classificadas quanto às seguintes variáveis maternas: idade, estado nutricional pré-gestacional, ganho de peso gestacional, paridade e tipo de parto. Amostras de soro e colostro foram coletadas em jejum no pós-parto imediato e o alfa-tocoferol foi analisado por cromatografia líquida de alta eficiência (CLAE). Para definir o estado nutricional de vitamina E, foi adotado ponto de corte sérico (697,7 μg/dL). A análise estatística foi realizada com o uso do teste t de Student para amostras independentes e correlação de Pearson. As diferenças foram consideradas significativas quando pPURPOSE: To determine the nutritional status of vitamin E in breastfeeding women through the analysis of alpha-tocopherol concentration in serum and colostrum, to analyze its relation with maternal variables and to determine the prevalence of vitamin E deficiency in these women. METHODS: The study included 103 mothers who were classified according to maternal variables: age, nutritional status before pregnancy, gestational weight gain, parity and mode of delivery. Colostrum and serum samples were collected under fasting conditions in the immediate postpartum period. Alpha-tocopherol was analyzed by high performance liquid chromatography (HPLC). A serum cutoff of 697.7 μg/dL was adopted to define the nutritional status of vitamin E. Statistical analysis was performed with the Student's t test for independent samples and Pearson's correlation. Differences were significant when p<0.05. RESULTS: The average concentration of alpha-tocopherol was 1.125±551.0 μg/dL in colostrum and 1,138.6±346.0 μg/dL in serum, indicating adequate biochemical nutritional status. However, when analyzing the mothers individually, a 16% rate of subclinical vitamin E deficiency was detected. Women undergoing cesarean delivery had significantly higher alpha-tocopherol levels in colostrum (1.280±591 μg/dL) compared with those undergoing normal delivery (961.7±370 μg/dL) (p<0.05). It was found that mothers who were overweight before pregnancy had higher vitamin concentration in colostrum (1,331.5±548 μg/dL) when compared to underweight women (982.1±374 μg/dL) or women of normal weight (992.3±346 μg/dL) (p<0.05). However, the other variables were not associated with alpha-tocopherol in colostrum. Moreover, no variable showed association with vitamin E levels in maternal serum and no correlation was demonstrated between the alpha-tocopherol levels in serum and in milk. CONCLUSIONS: Despite the diagnosis of satisfactory nutritional status, breastfeeding women showed significant risk of subclinical vitamin E deficiency. We suggest that the concentration of alpha-tocopherol in colostrum be associated with type of delivery and pre-gestational nutritional status of women.
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