How fat absorption is directed by specific bacteria in the small intestine
An exciting new study has examined how bacteria in the small intestine help digest and absorb high-fat foods. The novel research suggests that in the future we could potentially combat obesity by inhibiting the abundance of certain bacteria that promote fat absorption.
The team of researchers from the University of Chicago set out to understand what role gut bacteria played in the digestion and absorption of fats. The study focused on the small intestine, a vastly understudied region of microbiome according to senior author Eugene B. Chang.
"Few people have focused on the microbiome of the small intestine, but this is where most vitamins and other micronutrients are digested and absorbed," explains Chang.
The study began by examining germ-free mice, with no intestinal bacteria. These mice with no gut bacteria were fed high-fat diets yet they did not gain weight. Instead they were found to be excreting the fats in their stool. A second type of mouse model was then studied. Called "specific pathogen free (SPF)," these mice were healthy but bred to harbor a large variety of regular, non-disease causing gut bacteria.
The SPF mice did gain weight on a high-fat diet and the researchers identified certain strains of bacteria increasing in the small intestine, seemingly attracted by the high-fat foods. Bacteria from the Clostridiaceae and Peptostreptococcaceae families became abundant in the small intestine while other microbes, including members of the Bifidobacteriacaea and Bacteriodacaea families, notably decreased.
"Certain dietary pressures, such as calorie-dense foods, attract specific bacterial strains into the small intestine," says Chang, "These microbes are then able to allow the host to digest this high-fat diet and absorb fats. That can even impact extra-intestinal organs such as the pancreas."
This is one of the first studies to elucidate how bacteria in the small intestine can directly regulate the absorption of fats. It is still early stages for the research and so far it has only been established in mouse models, but it does suggest small intestine bacteria could play a very important role in the development of obesity.
"Our results suggest that maybe we could use pre- or probiotics or even develop post-biotics (bacterial-derived compounds or metabolites) to enhance nutrient uptake for people with malabsorption disorders, such as Crohn's disease, or we could test novel ways to decrease obesity," notes lead author of the study Kristina Martinez-Guryn.
The study was published in the journal Cell Host & Microbe.