Bile Composition of Adult Baboons Is Influenced by Breast Versus Formula Feeding

Abstract

SummaryWe tested the hypothesis that infant cholesterol intake and breast‐ versus formula‐feeding influence the bile cholesterol saturation index and bile acid conjugate composition in adult baboons at 7–8 years of age. We also measured the influence of the postweaning intake of dietary cholesterol and fat (saturated and unsaturated) on the effects of the infant diets. The 80 baboons were derived from six sires and 80 dams and randomly assigned at birth to breast‐feeding or to one of three formulas containing about 2, 30, or 60 mg cholesterol/dl. After weaning at 16 weeks of age the animals were assigned to one of four adult diets, which contained 0.01 or 1.0 mg/kcal of cholesterol containing 40% of calories from saturated or unsaturated fat. The bile cholesterol saturation index was significantly higher at 7–8 years of age in baboons breastfed as infants compared with those fed formula (87.0% versus 72.8%, p < 0.004). The cholesterol saturation index was not significantly different among the three formula groups. Among baboons who were breast‐fed and subsequently fed saturated fat as adults, the glycine/ taurine (G/T) ratios of the bile acid conjugates were about three times those of baboons fed unsaturated fat (1.53 versus 0.47); whereas among formula‐fed animals the type of fat did not influence the G/T ratio (interaction, p = 0.022). Adult baboons fed the three formulas in infancy had an inverse relationship of the G/T ratio to the level of formula cholesterol (p < 0.05), We conclude that breastfeeding and formula feeding in infancy differentially affect biliary lipid composition and its response to dietary cholesterol and fat in adulthood. These deferred effects of infant diet on bile lipid composition may influence gallstone formation and intestinal cholesterol and bile acid metabolism.