Rich in fat, sugar, and animal protein, the quintessential modern Western diet is often deficient in plant-derived fibers and thought to disrupt the delicate balance of human gut microbes. To explore the effects of diet on gut microbiomes, researchers sequenced DNA extracted from fecal samples from two primate species—red-shanked douc and mantled howling monkey—that were raised in zoos, sanctuaries, and nature, representing captive, semicaptive, and wild settings, respectively.

Despite being raised on vastly divergent diets in zoos as far-flung as Southeast Asia and the United States, captive primates, unlike wild-reared individuals, displayed similar gut microbiome compositions to modern humans, including a predominance of Prevotella and Bacteroidesspecies.

Sanctuary-reared primates that were fed a plant-based diet that included some of the plants available to wild-reared primates displayed middling levels of microbiome diversity and disruption, compared with zoo-reared primates of the same species.

Further, microbiome disruption was significantly associated with changes in dietary fiber content, but not with factors such as geographic location and antibiotic use, suggesting that diet largely influences microbiome composition in captive primates.

According to the authors, the findings underscore the link between fiber-rich diets and gut microbiome diversity.

http://www.pnas.org/content/early/2016/08/24/1521835113