IMPAIRMENT OF INTESTINAL HYDROLYSIS OF LACTOSE IN NEWBORN INFANTS

Abstract

A total of 122 oral lactose, glucose, glucose-galactose, and intravenous galactose tolerance tests were performed on 38 premature infants age 0-44 days and on 11 term infants age 0-3 days with the following conclusions: 1. Median fasting blood glucose levels were lower in premature infants than in term infants; values in premature infants rose steadily from 36 mg/100 ml in infants less than 3 days of age to 70 mg/100 ml in infants over 15 days of age. 2. Following orally administered lactose, 30- and 60-minute increments in blood glucose values were significantly less in premature and term infants younger than 3 days than in older infants. This was not true following oral administration of glucose. 3. In premature infants 0-3 days of age, 30- and 60-minute increments were significantly less following lactose than after either glucose or glucose-galactose. After 2 weeks of age, lactose tolerance tests were similar to glucose tolerance tests. 4. Intravenous galactose tolerance tests showed competent conversion of galactose to glucose in all age groups. 5. Significantly greater increments in blood glucose values were observed in premature and term infants less than 3 days of age when lactase was introduced into the duodenum prior to lactose administration. From the present study, it appears that hydrolysis of lactose in the intestine of the newborn infant is relatively impaired during the first few days of life. Further studies with quantitative assays of lactase activity in the intestinal epithelial cells will be necessary to determine whether an absolute insufficiency of lactase exists at birth.