Association of Estimated Daily Lactose Consumption, Lactase Persistence Genotype (rs4988235), and Gut Microbiota in Healthy U.S. Adults

Abstract

Abstract Objectives Lactase persistence (LP) is a heritable trait in which lactose can be digested into adulthood. Lactase non-persisters (LNP) who consume lactose may experience microbial adaptations in response to the undigested lactose. The objective of this study was to determine the interaction between lactose consumption, LP genotype and gut microbiota in an observational cross-sectional study of healthy U.S. adults. Methods ASA24 dietary data and stool samples were collected from healthy U.S. adults genotyped for the lactase persistence SNP ID: rs4988235 (n = 280). Lactose was estimated by matching ASA24-reported foods to foods in the Nutrition Coordinating Center Food and Nutrient Database. The 16S rRNA V4/V5 region, amplified from bacterial DNA extracted from each frozen stool sample, was sequenced using Illumina MiSeq (300bp PE) and analyzed using Qiime 2 (v 2019.10). Bacterial sequence counts present at greater than 0.1% of the total data set were analyzed using DESeq2 and LEfSe. Taxa that were differentially abundant by both analyses at the family or genus level are reported here. Results On average 246 ng/uL (3.9 – 646.5ng/uL) DNA was obtained from each sample, yielding 21,470 sequences (10,122 – 56,837). LP genotypes were unevenly distributed by ethnicity and Clostridium (family Lachnospiraceae) was significantly enriched in Asian ethnicities. Therefore, only Caucasian and Hispanic participants were grouped as LP (AA or AG genotype) or LNP (GG genotype) for further analysis. The abundance of Roseburia and family Lachnospriaceae was higher in the upper (>12.4g), relative to lower (< 5.78g), tertile of lactose consumption in LNP adults, but not in LP. Conclusions Increased abundance of Roseburia, a microbe capable of utilizing lactose, in LNP individuals consuming >12.4 g lactose/day suggests that this genus may metabolize lactose in LNP adults. Funding Sources The California Dairy Research Foundation and the United States Department of Agriculture, Agricultural Research Service.