Reduced rate of breath hydrogen excretion with lactose tolerance tests in young children using whole milk.

On 14 occasions, 1.75 g/kg of body weight of lactose was given in whole milk to preschool children who had significant malabsorption with aqueous lactose solution. The volume of hydrogen excreted in the breath was less after the milk meal. Moreover, the hydrogen response to the nonabsorbable disaccharide, lactulose, was greater with aqueous, solution than with a liquid meal but their difference disappeared when metoclopramide was given with the lactulose: meal. The slower hydrogen production is attributed to slower intestinal delivery of lactose in meals; this phenomenon may account for clinical lactose tolerance often seen in children with demonstrated lactose malabsorption.