Nonlipid formula components and fat absorption in the low-birth-weight newborn.

The relationship between nonlipid formula components and fat absorption in newborns is largely uninvestigated. Two formulas of identical fat blend but different protein quality and acid-base properties were fed to two groups of babies from birth and during 3-5 d balance periods in the third week of life. Babies receiving a formula of higher acidity containing predominantly curd protein absorbed a significantly lower percentage of their fat and nitrogen intake than babies receiving a curd-and-whey protein formula (fat absorptions of 73 +/- 11.0 and 85 +/- 8.0%, means +/- SD, p less than 0.04; N absorptions of 90 +/- 3.0 and 93 +/- 1.0%, p less than 0.03, respectively). The feces of the curd-formula babies contained a smaller proportion of long-chain, saturated fatty acids and a larger proportion of shorter-chain and unsaturated fatty acids. Fatty acid type and triglyceride structure are not the only factors influencing fat absorption in newborns. Other formula components may need modification to achieve maximum fat absorption.