Low Vitamin A Paves Road to Iron Deficiency 32623

Low Vitamin A Paves Road to Iron Deficiency

DAVIS, Calif.--According to a study published in the January issue ofThe Journal of Nutrition (135:27-32, 2005) (www.nutrition.org)low maternal levels of vitamin A may leave breastfed offspring at risk for irondeficiency. University of California researchers hypothesized low vitamin Aintake during lactation elicits differential effects on mammary gland and liveriron transport and storage proteins, thus affecting the iron concentration inmilk, but not maternal iron status.

A positive correlation between maternal iron status and iron levels in milkwere observed in lactating women supplemented with both vitamin A and iron, butnot with iron alone. The scientists fed rats either a control diet or a marginalvitamin A diet--containing one-tenth of the vitamin A given in the controldiet--through mid-lactation. Effects on plasma, milk, liver and mammary glandiron and vitamin A concentrations, and divalent metal transporter-1 (DMT1),ferroportin (FPN), ferritin, and transferrin receptor (TfR) expression weredetermined. The rats fed the vitamin A diet were not vitamin A or iron deficientat the onset of the study.

Milk and liver vitamin A and iron levels, as well as mammary gland ironconcentrations were lower, liver TfR expression was higher, and mammary glandTfR expression was lower in rats fed the vitamin A diet compared with rats fedthe control diet. Liver Ft was unaffected, yet mammary gland ferritin was lowerin the vitamin A fed rats compared with those on the control diet. Liver andmammary gland DMT1 and FPN protein levels were lower in the vitamin A ratscompared with the control.

The researchers concluded the mammary gland and the liver respond differentlyto marginal vitamin A intake during lactation, causing iron levels in milk tobecome significantly decreased due to effects on mammary gland irontransporters, thereby putting the nursing offspring at risk for iron deficiency.