Population-level variation in gut bifidobacterial composition and association with geography, age, ethnicity, and staple food

Abstract

Bifidobacteria are key gut commensals that confer various health benefits and are commonly used as probiotics. However, little is known about the population-level variation in gut bifidobacterial composition and its affecting factors. Therefore, we analyzed Bifidobacterium species with amplicon sequencing of the groEL gene on fecal samples of 1674 healthy individuals, who belonged to eight ethnic groups and resided in 60 counties/cities of 28 provinces across China. We found that the composition of the bifidobacterial community was associated with geographical factors, demographic characteristics, staple food type, and urbanization. First, geography, which reflects a mixed effect of other variables, explained the largest variation in the bifidobacterial profile. Second, middle adolescence (age 14–17) and age 30 were two key change points in the bifidobacterial community development, and a bifidobacterial community resembling that of adults occurred in middle adolescence, which is much later than the maturation of the whole gut microbial community at approximately age 3. Third, each ethnicity showed a distinct bifidobacterial profile, and the remarkable amount of unknown Bifidobacterium species in the Tibetan gut suggested undiscovered biodiversity. Fourth, wheat as the main staple food promoted the flourish of B. adolescentis and B. longum. Fifth, alpha diversity of the bifidobacterial community decreased with urbanization. Collectively, our findings provide insight into the environmental and host factors that shape the human gut bifidobacterial community, which is fundamental for precision probiotics.

Cross-feeding of bifidobacteria promotes intestinal homeostasis: a lifelong perspective on the host health

“…B . adolescentis prefers (A)XOS to arabinose or xylose, and encodes a gene for endo-1,4-β-xylanase capable of growing on wheat AX 9 , 14 , 79 .…”

“…In adulthood, the relative abundance of bifidobacteria decreases to approximately 10%, however remains stable, whereas that in aging individuals accounts for approximately 5% of the total gut bacteria 6 . In infancy, Bifidobacterium breve , B. longum , and B. bifidum are commonly found in feces 7 , while in adulthood, B. adolescentis , B. longum , and B. pseudocatenulatum are the dominant species 8 , 9 . The relative abundance of B .…”