Gut Microbes Increase Absorption of Dietary Fats

A family of gut microbes have great role in processing fat and fat metabolism.

A new study by from the University of North Carolina school of Medicines underscore the complex relationship between microbes, diet and host physiology.

The vast community of microbes residing in the digestive tract help in increasing the absorption of dietary fats. This processin turn makes the host organism to extract 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," said senior study author John Rawls, PhD, associate professor in the Department of Cell and Molecular Physiology at UNC.

Prior to this there were studies done that revealed the microbe's aid in breakdown of complex carbohydrates. But this is the first study that highlights the role of microbes in dietary fat metabolism.

The result of this finding was carried in the Sept. 13, 2012 issue of the journal Cell Host & Microbe.

To prove their finding the researchers used a zebrafish that are optically transparent when they are young. They fed the fish with fatty acids tagged with fluorescent dye. On doing this the researchers were able to clearly observe the absorption and transport of fats in the presence and absence of gut microbes.

According to the researchers Firmicutes group of bacteria are responsible in increasing fat absorption. Excess of Firmicutes in the gut was influenced by diet: fish fed normally had more Firmicutes bacteria compared to fish that were denied food for several days. Other studies have linked a higher relative abundance of Firmicutes in the gut with obesity in humans.

"Our findings indicate that the gut microbiota can increase the host's ability to harvest calories from the diet by stimulating fat absorption," said the study's lead researcher, Ivana Semova, PhD, who was a graduate student at UNC at the time the study was conducted. "Another implication is that diet history could impact fat absorption by changing the abundance of certain microbes, such as Firmicutes, that promote fat absorption."

"Although the study involved only fish, not humans, it offers insights that could help inform new approaches to treating obesity and other disorders." For example, said Rawls, "If we can understand how specific gut bacteria are able to stimulate absorption of dietary fat, we may be able to use that information to develop new ways to reduce fat absorption in the context of obesity and associated metabolic diseases, and to enhance fat absorption in the context of malnutrition."