Comparison of gas composition and production by feces of breast-fed infants vs. formula-fed infants

Abstract

Colic commonly is thought to be a manifestation of excessive intestinal gas, and this gas commonly is attributed to the infant's diet. A recent study indicated that breast-fed infants experienced less colic than did formula-fed infants. The aim of this study was to determine if the volume or composition of gas produced by the feces of breast-fed infants differs from that of formula-fed infants. To this end, 18 healthy infants were divided into three groups according to their diets (beginning at birth): I) breast milk (n = 10); 2) milk-based formula (n = 3) and; 3) soy-based formula (n =5). Fresh fecal samples, collected at 4, 8 and 12 weeks of age, were anaerobically incubated for four hours at 37°C in a sealed container, and the production of bacterial gases (H2S, CH3SH, CO2, H2, and CH4) was measured. Data for the one month measurement are shown in the Table. The most striking finding was that feces from breast-fed infants produced much less H2S and CH3SH than did feces from formula-fed infants. The extremely noxious odor of these two gases probably accounts for the well known difference in odor of breast versus formula-fed infants. In addition, the sulfur-containing gases are highly toxic and irritating to mucosal membranes. While speculative, it seems possible that the mucosal enzyme systems that detoxifies these compounds in adults are not fully developed in infants. Inadequate detoxification might result in colonic irritation and symptoms of colic.