Effect of iron-fortified formula on SIgA of gastrointestinal tract in early infancy.

Abstract

There is no information available about the effect of iron in formula on the development of gastrointestinal humoral immune response in early human infancy. We compared standard Enfamil to iron-fortified formula during the first 8 weeks of human life on the development of local gastrointestinal humoral immune response by measuring fecal secretory immunoglobulin A (SIgA). Thirty children were studied and classified according to feeding in two groups: plain Enfamil (n = 15) and Enfamil with iron (n = 15). Fecal specimens were analyzed at birth, 2 weeks, 4 weeks, and 8 weeks of age. Fecal SIgA was assayed by RID (radial-immune diffusion) during these four infantile periods in the two groups. Marked SIgA changes were detected in the group with iron-fortified formula versus non-iron-fortified formula. These changes appeared to have statistical significance in all the three infantile periods (2 weeks, 4 weeks, and 8 weeks). There were no observed clinical side effects with the use of iron-fortified formula as detected by appropriate questionnaire. The possible role of iron in earlier and enhanced development of immunologic competence and host defense is discussed. These data may suggest a beneficial effect of low-dose iron in formula during early infantile human life by the protective role of the earlier and enhanced production of SIgA in the gut.