Some gut microbes help the body absorb more dietary fat, which means their host takes in more calories from the same amount of food.
“This study is the first to demonstrate that microbes can promote the absorption of dietary fats in the intestine and their subsequent metabolism in the body,” says senior study author John Rawls, associate professor in the department of cell and molecular physiology at University of North Carolina School of Medicine.
“The results underscore the complex relationship between microbes, diet, and host physiology.”
Previous studies showed gut microbes aid in the breakdown of complex carbohydrates, but their role in dietary fat metabolism remained a mystery, until now. The research is published in the September 13 issue of the journal Cell Host & Microbe.
The study was carried out in zebrafish, which are optically transparent when young. By feeding the fish fatty acids tagged with fluorescent dye, the researchers were able to directly observe the absorption and transport of fats in the presence or absence of gut microbes.