Micronutrients and susceptibility to infection.

Iron deficiency and vitamin A deficiency are both reported to predispose to infection morbidity and to mortality. In both situations, however, the data are insufficient to draw firm conclusions, primarily owing to flaws in the design of the studies. To be sure, these are difficult studies to carry out, and the investigators whose reports have been reviewed should be praised rather than adversely criticized for their efforts. In the case of iron deficiency, there is a further complication in interpretation, that is the suggestion that iron deficiency states may be protective and that conditions of iron overload may predispose to infection. These concepts appear to pertain most convincingly to malaria and Yersinia infections, and to situations in which iron dextran is given parenterally to young children in the first few months of life. There are still two few data to suggest that oral iron is harmful and there is no reason at present that it should not be employed for the correction of iron deficiency anemia.