ABSTRACT
Twenty-eight Sioux and 29 Saluteaux Indians from a southern and an isolated northern Manitoban community were screened for lactose malabsorption; 55 were also screened for sucrose tolerance. Sixty percent of the subjects were lactose malabsorbers; the incidence increased with age. Lactase deficiency appeared, on the average, between 8 and 15 years of age. About 45% of the subjects were lactose intolerant. Malabsorbers who did not regularly drink milk had the highest symptom scores. The northern subjects consumed significantly more lactose and sucrose than the southern subjects. Two Sioux children were sucrose malabsorbers. It was hypothesized that the significantly greater sucrose consumption by the Saulteaux subjects were responsible for their markedly higher blood glucose curve following the sucrose tolerance tests. Dietary sucrose increases jejunal sucrase activity and the intestinal transport of glucose and fructose. Three of eight children less than 4 years were lactose malabsorbers; hence, medical personnel treating noninjective diarrhea in Indian children should examine for lactase deficiency. It was recommended that vitamin D fortified milk supplements to Indian school children be continued and that the milk be treated so as to reduce abdominal symptoms in the intolerant individuals.