Interaction of iron and folate during reproduction.

Biochemical evidence collected from both clinical and non-institutionalized populations indicate that iron and folate deficiencies frequently occur simultaneously. Supplementation trials of iron-deficient patients with either iron or iron and folate has helped to illustrate that a complex interrelationship exists between these two nutrients. Controlled animal trials in which dietary iron and folate content has been systematically manipulated reveal that iron deficiency can cause altered folate utilization. The impact of iron deficiency on folate metabolism is most dramatic during the reproductive and neonatal stages of the life cycle. Rat pups and piglets nursed by dams fed iron-depleted diets exhibit signs of altered folate utilization. Depressed milk folate secretion is an early manifestation of iron deficiency in the rat dam and is a prime factor responsible for folate depletion in their nursing pups. Impaired milk folate secretion during iron deficiency is not due to a decrease in the amount of folate supplied to the mammary gland; rather, the defect causing this reduction is specific to the mammary gland.