Intestinal blood loss during cow milk feeding in older infants - Quantitative measurements

Objective: To determine the response, in terms of fecal hemoglobin excretio n and clinical symptoms, of normal 9 1/2-month-old infants to being fed cow milk. Design: Longitudinal (before-after) trial in which each infant: was fed for mula for 1 month (baseline) followed by 3 months during which cow milk was fed. Setting: Healthy infants living in Iowa City, Iowa, a town with a populatio n of about 60 000. Main Outcome Measures: Hemoglobin concentration ill spot stools, 96-hour qu antitative fecal hemoglobin excretion, stool characteristics, feeding-relat ed behaviors, and iron nutritional status. Results: Fecal hemoglobin concentration during formula feeding (baseline) w as higher than previously observed in younger infants, Nine of 31 infants r esponded to cow milk feeding with increased fecal hemoglobin concentration. Fecal hemoglobin concentration (mean +/- SD) of the 9 responders rose from 1395 +/- 856 mu g/g of dry stool (baseline) to 2711 +/- 1732 mu g/g of dry stool (P = .01). The response rate (29%) was similar to that in younger in fants, but the intensity of the response was much less. Quantitative hemogl obin excretion was in general agreement with estimates based on spot stool hemoglobin concentrations. Cow milk feeding was not associated with recogni zable changes in stool characteristics, nor were there clinical signs relat ed to fecal blood loss. Iron status was similar, except that after 3 months of cow milk feeding responders showed lower (P = .047) ferritin concentrat ions than nonresponders. Conclusions: Cow milk-induced blood loss is present in 9 1/2-month-old infa nts but is of such low intensity that its clinical significance seems quest ionable. Nevertheless, infants without cow milk-induced blood loss were in better iron nutritional status than infants who showed blood loss.