Gut microbiomes and the modern diet

Diets poor in plant-based fibres may be associated with imbalance and reduced diversity of human gut microbiomes, a study has suggested.

Rich in fat, sugar and animal protein, the quintessential modern Western diet is often deficient in plant-derived fibres. To explore the effects of diet on gut microbiomes, Dan Knights and colleagues from the University of Minnesota sequenced DNA extracted from faecal samples from two primate species — red-shanked douc and mantled howling monkey — that were raised in zoos, sanctuaries and nature, representing captive, semi-captive 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 Bacteroides species.

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

Microbiome disruption was significantly associated with changes in dietary fibre content but not with factors such as geographic location and antibiotic usage, suggesting that diet largely influences microbiome composition in captive primates. According to the authors, the findings underscore the link between fibre-rich diets and gut microbiome diversity.

The research has been published in PNAS.