Intestinal lactase deficiency in an apparently normal Peruvian population.

The prevalence of milk and lactose intolerance and intestinal lactase deficiency was studied in 30 apparently healthy Peruvian individuals. At the same time, 20 milk-intolerant persons were included in the study. According to the results of lactose-tolerance tests and intestinal lactase assays, one-third of the 30 were considered normal and were used as controls. The other two-thirds were found to be abnormal and were referred to asasymptomatics; they tolerated well small amounts of milk consumed daily. Upon lactose load, they developed gastro-intestinal symptoms, and maximal rise of blood glucose was below normal limits. Enzymatic assay indicated that they were deficient in intestinal lactase.