Relationship between the dietary intake, serum, and breast milk concentrations of vitamin A and vitamin E in a cohort of women over the course of lactation.

This study evaluated the nutritional status of lactating women with regard to vitamins A and E and the relationship between dietary intake and concentrations in serum and milk. A longitudinal study was conducted with 43 women at a hospital in northeastern Brazil. Blood and milk samples and food intake recalls were obtained at three moments during the breastfeeding period. Retinol and alpha-tocopherol were analysed by high-performance liquid chromatography. Dietary inadequacy was analysed according to the estimated average requirement, with intrapersonal variation adjusted by the multiple source method. Food intake was classified by quartiles of consumption. Serum retinol was 1.65 μmol/L, with 5% of low concentrations (<0.7 μmol/L) at the first collection. Serum alpha-tocopherol decreased from 30.18 to 25.49 μmol/L at the third collection (P = 0.008), with an increase in the percentage frequency of deficiency (<12 μmol/L). Both vitamins maintained stable concentrations in milk at the different collection times, and the overall dietary inadequacy of vitamins A and E was 58% and 100%, respectively. There was a correlation only between vitamin A intake and serum retinol (r = 0.403, P = 0.007), and higher retinol concentrations were found in women classified in the highest consumption quartile (P = 0.031). Over the course of lactation, there was a high degree of inadequacy in vitamin intake and a reduction in serum alpha-tocopherol, whereas its concentrations in milk remained unchanged. Dietary intake of vitamin A has been shown to influence serum retinol, which underscores the importance of adequate nutrition and monitoring of vitamin deficiency during lactation.