Influence of maternal selenium status on human milk selenium concentration and glutathione peroxidase activity

This study assessed whether relationships existed between maternal indices of selenium (Se) nutrition and milk content of Se and activity of glutathione peroxidase (GSH-Px). Samples of milk (n = 72) collected at 4, 8, 12, and 16 wk postpartum and blood from lactating (n = 10) and control (n = 8) women were analyzed. Plasma and erythrocyte Se concentrations and plasma GSH-Px activity were significantly lower in lactating than in control women. Maternal plasma Se concentration was positively correlated with plasma GSH-Px activity (r = 0.53, p less than 0.01) and with milk Se content (r = 0.61, p less than 0.01) and GSH-Px activity (r = 0.51, p less than 0.01). Stage of lactation did not influence either milk or blood values. Milk Se concentration was positively correlated with milk GSH-Px activity (r = 0.81, p less than 0.001). Results indicate that human milk Se content and GSH-Px activity are directly influenced by maternal Se nutrition.