Postnatal caffeine effects on copper, zinc, and iron concentrations in mammary gland, milk, and plasma of lactating dams and their offspring.

Beginning on the day of delivery and until the 15th or 22nd day of lactation, one group of dams received a 20% protein diet as a basal diet and one group received the basal diet supplemented with caffeine (4 mg/100 g body weight). A correlation between caffeine concentrations in the dams' plasma and milk was observed. In the caffeine group, levels of Fe and Cu in the dams' mammary glands at day 22 were decreased. Copper levels in the milk at day 15 and Fe and Zn levels in the milk at day 22 showed a significant decrease. Copper concentration in the plasma of 15-day-old pups showed a significant decrease also, but Zn and Fe concentration showed no difference between caffeine and noncaffeine control groups. The present study shows that the dams' consumption of a caffeine-containing diet influences trace elements of mammary glands, milk, and pups' plasma.