Avaliação da suplementação materna com palmitato de retinila sobre os níveis de retinol e alfa-tocoferol no leite humano

Abstract

Vitamins A and E are lipophilic nutrients that act in many important biological processes, such as immunity, reproduction, growth, and development. These vitamins are essential during the initial phase of life and should be properly transferred from mother to child during pregnancy and lactation. Maternal supplementation with vitamin A is one of the strategies for controlling its deficiency in the mother-child dyad, but studies with animals showed that supplementation with high doses of vitamin A reduces the levels of alpha-tocopherol (vitamin E) in the mother’s serum and milk. Hence, the objective of this study was to assess the influence of maternal supplementation with vitamin A on the concentration of retinol and alpha-tocopherol in colostrum and mature milk. Healthy puerperal women with term deliveries were randomly distributed into a control group (n=44) and a supplemented group (n=44). Blood and colostrum samples were collected immediately after delivery, and mature blood samples were collected 30 days later. The supplemented group received 200,000 IU of retinyl palmitate immediately after the first colostrum collection. The retinol and alpha-tocopherol levels in the biological samples were determined by high-performance liquid chromatography (HPLC). Serum vitamin A levels below 20 µg/dL and serum vitamin E levels below 516 µg/dL indicated deficiency. The retinol and alpha-tocopherol levels in the maternal serum were considered adequate at 46.4 ± 15.9 µg/ dL and 1,023.6 ± 380.4 µg/ dL, respectively. The colostrum retinol levels of the supplemented group increased significantly 24 hours after the intervention (p<0.001). However, the retinol levels in the mature milk of both groups did not differ (p>0.05). Moreover, after maternal supplementation with vitamin A, colostrum alpha-tocopherol level decreased by 16.4%, a significant reduction (p<0.05). However, vitamin A supplementation did not affect the alpha-tocopherol level of mature milk (p>0.05). In conclusion, maternal supplementation with high doses of vitamin A increased the colostrum level of this nutrient but reduced the bioavailability of alpha-tocopherol, which may harm the newborn’s health since newborns have limited vitamin E reserves.