Chapter 4 - Host, Genetic, and Environmental Influences on the Gut Microbiota

Abstract

A combination of factors, including aspects of host physiology, genetics, and environment, contribute to the gut microbiome variations observed from person to person. Stool consistency or transit time has emerged as an intrinsic (host) factor that influences gut microbiota composition. Further, evidence shows some heritable taxa exist, with some microbiome-gene associations evident in association studies. The environmental factors that account for the most variance in gut microbiota composition are diet and medications, with medications explaining the largest total variance in composition between individuals. Interactions between drugs and gut microbiota are complex; studies show the gut microbiota composition of healthy adults appears largely resilient to perturbation by a course of antibiotics, but community composition may fail to recover in some individuals. Additional factors that influence gut microbiota composition are an individual’s geographic location, living environment (i.e., farm and pet exposure), household members, outdoor environment, physical exercise/fitness, psychological stress, sleep, smoking, and even drinking water.