470 EFFECT OF DIET AND LIGHT ON INTESTINAL LACTASE IN NEONATES

Abstract

Thirty newborns were divided into 3 groups of 10 each: Gp. A well, non-jaundiced, Gp. B jaundiced but not under phototherapy, Gp. C phototherapy for hyperbilirubinemia. Each infant was assigned randomly either cow's milk formula or a soy milk formula (lactose-free). Stools were observed daily for character, pH, and reducing substances. Lactose Tolerance Tests were done daily for 3 days - in Gp. C prior to, during and after phototherapy. Birth wts. ranged from 2120 to 3870 gm (mean 3280 gm) Only infants with physiologic jaundice were included. Group A infants had normal stools, normal LTT, as did infants in Group B. In Gp. C, infants on cow's milk feeding had abnormal LTT, lowered stool pH and 3-4+ reducing substances, loose dark stools. Those in Gp. C on soy milk feeding had equivocal LTT, stools normal in color, consistency, pH, and no reducing substances. We conclude that hyperbilirubinemia itself does not affect lactase activity in the small intestine, but that phototherapy does cause lactase deficiency, either directly by radiation, or by the presence of bilirubin photoproducts or isomers. The use of a soy milk formula, containing sucrose rather than lactose, does not alter lactase activity significantly, but does correct CHO digestion by substituting sucrose, whose intestinal enzyme is unaffected by phototherapy.