Abstract
Small intestinal lactase activity in the healthy adult is either the same as in early infancy or may drop to very low levels. The incidence varies with the ethnic qroup studied but very little information is available as to the age lactase decreases. We selected 150 specimens with normal histologic appearance out of 1047 mucosal biopsies. They were derived from a heterogenous white ethnic group with failure to thrive, healthy siblings and parents, ranging in age from 6 weeks to 50 years. Mucosal lactase activity and sucrase/lactase ratios in these 150 subjects were plotted against their age. In the first 3 years of life lactase activity averaged 32.1±10.1 Mmoles/αP/min. and sucrase/lactase ratio was 1.7 ± 0.5. There was no significant difference in mean or S.D.from year to year in the first three years. After the age of 5, two separate groups emerged. One group with low lactase activity and the other with the same mean value as in the first three years. The group with low lactase included children and adults with clinical lactose intolerance and some (8) upon testing, had a flat lactose tolerance test. They consumed relatively small amounts of milk. The other qroup with high lactase activity consumed an average of one ouart of milk a day, and some (3) on testing, had a normal lactose tolerance test. This study implies that healthy Caucasian children up to age of 5 can safely consume milk without fear of lactose intolerance.
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Lebenthal, E., Antonowicz, I. & Shwachnan, H. CRITICAL AGE OF LACTASE DEFICIENCY IN CAUCASIANS. Pediatr Res 8, 383 (1974). https://doi.org/10.1203/00006450-197404000-00257
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DOI: https://doi.org/10.1203/00006450-197404000-00257