Lack of Effect of Lactose Digestion Status on Baseline Fecal Microflora

Abstract

BACKGROUND: The genetics of intestinal lactase divide the world’s population into two phenotypes: the ability (a dominant trait) or inability (a recessive trait) to digest lactose. A prebiotic effect of lactose may impact the colonic flora of these phenotypes differently.OBJECTIVE: To detect and evaluate the effects of lactose on subjects divided according to their ability to digest lactose.METHODS: A total of 57 healthy maldigesters (n=30) and digesters (n=27) completed diet questionnaires, genetic and breath hydrogen testing, and quantitative stool analysis for species of bacteria. Log₁₀ transformation of bacterial counts was compared with lactose intake in both groups using multiple regression analysis.RESULTS: There was a significant relationship between genetic and breath hydrogen tests. Daily lactose intake was marginally lower in lactose maldigesters (median [interquartile range] 12.2 g [31 g] versus 15 g [29.6 g], respectively). There was no relationship between lactose intake and breath hydrogen tests in either group. There were no differences in bacterial counts between the two groups, nor was there a relationship between bacterial counts and lactose intake in either group.CONCLUSION: The differential bacterial effects of lactose were not quantitatively detected in stool samples taken in the present study.