Gut transit time and lactose malabsorption during phototherapy. I. A study using lactose-free human mature milk.

Sixty newborn infants with normal birth weight suffering from uncomplicated hyperbilirubinemia were studied. They were fed human mature milk from which lactose had been eliminated, whereafter either sucrose ("sucrose milk") or lactose ("lactose milk") was added. 30 infants received ordinary phototherapy and 30 intensive phototherapy (blue double light). 15 in each group had "sucrose milk" and 15 "lactose milk". There was no significant difference between the increase in blood glucose (delta BS) by lactose tolerance tests performed before phototherapy (LTT1) and by those performed during phototherapy (LTT11), neither in infants treated with ordinary nor with intensive phototherapy. All infants had normal delta BS-LTT11, except one receiving ordinary phototherapy. There was no significant difference in gut transit time between infants having "sucrose milk" and infants having "lactose milk", neither in those treated with ordinary nor with intensive phototherapy. Gut transit time was significantly shorter in infants treated with intensive phototherapy than in infants treated with ordinary phototherapy without there being any significant difference in delta BS-LTT11. The infant with flat LTT11 may have developed lactose malabsorption during the phototherapy. Thus, lactose malabsorption is not the usual cause of the reduced gut transit time during phototherapy and must be a rare complication in phototherapy.