STRUCTURAL POSITION AND AMOUNT OF PALMITIC ACID IN INFANT FORMULAS - EFFECTS ON FAT, FATTY-ACID, AND MINERAL BALANCE

The structure of the triglycerides (TG) in human milk (HM) differs fro m those of vegetable oils used in infant formulas. In HM, palmitic aci d is predominantly esterified to the center or beta-position of the TG , in vegetable oil, it is mainly at the external or alpha-positions. T hese differences in configuration affect intestinal fat absorption. Fa t and mineral balances were investigated in three groups of 9 healthy term infants aged 5 weeks. Infants were randomly assigned to receive o ne of the three study formulas from birth: (a) formula beta, resemblin g the structure of HM fat most closely (24% palmitic acid, 66% esterif ied to beta-position), (b) formula intermediate (24% palmitic acid, 39 % esterified to the beta-position), and (c) regular formula (20% palmi tic acid; 13% esterified to the beta-position). Fat absorption was hig hest in infants fed the beta formula (97.6 +/- 0.9%), intermediate in those fed with the intermediate formula (93.0 +/- 1.8%), and lowest in infants receiving the regular formula (90.4 +/- 4.6%). Fecal calcium excretion was significantly lower in the beta group than in the other two groups (43.3 +/- 18.1 vs. 59.9 +/- 15. 1 vs. 68.4 +/- 22.3 mg . kg (-1). day(-1) for beta, intermediate, and regular respectively). Dieta ry TG containing palmitic acid predominantly at the beta-position, as in HM, have significant beneficial effects on the intestinal absorptio n of fat and calcium in healthy term infants.