Wild Primate Gut Microbiota Protect Against Obesity

Abstract

The gastrointestinal tract hosts trillions of bacteria that play major roles in metabolism, immune system development, and pathogen resistance. Although there is increasing evidence that low dietary fiber in Westernized societies is associated with dramatic loss of natural human gut microbiome diversity, the role of this loss in obesity and inflammation is not well understood. Non-human primates (NHPs) can be used as model systems for studying the effects of diet and lifestyle disruption on the human gut microbiome. Captive primates are typically exposed to low-fiber diets and tend to have human-associated microbiota in place of their native microbiota. In order to explore interactions between the gut microbiota and dietary fiber, we transplanted captive and wild primate gut microbiota into germ-free mice and then exposed them to either a high- or low-fiber diet. We found that the group receiving low-fiber diet and captive primate microbiota became obese and had high levels of circulating inflammatory cytokines, while mice receiving high-fiber diet and wild primate microbiota remained healthy. Mice with the wild primate microbiota and low-fiber diet acquired intermediate levels of obesity, demonstrating an interaction between dietary fiber and the microbiota. These results show that the modern human gut microbiome interacts with low-fiber diets to cause inflammation and obesity, and suggest a possible clinical role for manipulation of the microbiota in the treatment of obesity.