Abstract 650 Poster Session II, Sunday, 5/2 (poster 160)

There is little information regarding intestinal blood loss and cow milk feeding in older infants. In this study we determined what percentage of normal infants aged 10 to 12 months respond to cow milk with intestinal blood loss and exactly how much blood they lose. We also determined iron nutritional status. Twenty-eight infants (17 males and 11 females) were enrolled before 9 months of age. They were fed a milk-based formula for 4 wks as baseline, followed by cow milk for 3 months. Spot stools were collected at baseline, every other day during the first 2 wk of cow milk feeding and every 2 wks subsequently. In addition, 96-hr stool collections were performed at baseline and after 2, 4, 8, 12 wks of cow milk feeding. Fecal Hb was measured by the HemoQuant method. "Responders" were defined as infants who had 2 or more spot stools with hemoglobin (Hb) concentration greater than the baseline mean ± 2 SD value. Four capillary blood samples were obtained for determinations of ferritin and Hb. The baseline fecal Hb concentration in spot stools averaged 1234 µg/g dry stool (SD 628), which was almost twofold higher than observed previously in 5-month-old infants ( Ziegler et al., J Pediatr 1990;116:11-18). Seven infants (25%) were responders. During the first month of cow milk feeding, fecal Hb concentrations increased to 1703 ± 1249 µg/g. Although the increase was statistically significant (p= 0.012), it was much smaller than that in 5-month-old infants. Furthermore, it was not sustained during the subsequent 2 months. Compared to baseline (11.5 mg/d), 96-hr stool collections showed no significant increase in fecal Hb excretion during the entire cow milk feeding period (14.2, 11.9, 12.5, and 17.9 mg/d after 2, 4, 8, and 12 wks of cow milk feeding, respectively). The highest fecal Hb excretion was 37.5 mg/d, equivalent to an iron loss of 0.13 mg/d. Fecal Hb excretion in responders was not significantly different from that in nonresponders. The iron nutritional status of infants was satisfactory and did not change significantly during cow milk feeding. Thus, the study shows that at 10 to 12 months of age cow milk feeding no longer provokes significant intestinal blood loss.

(Supported by MCHB-MCJ-190808)