Effect of improved vitamin A status on response to iron supplementation in Pakistani infants

Abstract

We report an apparently protective effect of vitamin A in infants who received iron supplements (15 mg/d) for 3 mo. Those receiving iron showed increases in hemoglobin (8 g/L), ferritin (3.7 μg/L), and the acute-phase protein α1-antichymotrypsin (ACT: 0.06 g/L). In both the placebo and iron- supplemented groups there were increases in plasma retinol, lutein, α- tocopherol, immunoglobulin A, and immunoglobulin G. The improvement in vitamin A status could only have been from a seasonal increase in dietary sources of vitamin A, eg, breast milk and early weaning foods, and there were no obvious effects on iron utilization (hemoglobin concentrations). However, in the infants receiving iron, those whose retinol concentrations increased also showed reductions in ACT, ferritin, immunoglobulin A, and immunoglobulin M. Vitamin A is well known for its antiinfective properties and we suggest that these observations illustrate the importance of even small increases in dietary vitamin A or differences in vitamin A status in reducing the potentially toxic effects of iron supplements in persons in developing countries. These conclusions should now be confirmed with an intervention study to show that the benefits of vitamin A on iron status are due to reduced levels of infection.