Posted on Apr 22, 2018, 8 p.m.
Small intestine bacteria are key for fat absorption. High fat diets promote growth of microbes which boost lipid digestion and absorption, over time these microbes presence can lead to over-nutrition and obesity, as published in the journal Cell Host and Microbe.
Research has mostly focussed on gut microbiome bacteria and large intestine, this study concentrated on microbes in the upper gastrointestinal tract, showing how calorie dense western diets induce micobe expansion promoting fat digestion and absorption.
Several prior studies show bacteria can multiply within 24-48 hours within the small bowel in response to eating high fat foods, these findings suggest these microbes facilitate secretion and production of digestive enzymes in the small bowel, breaking down dietary fat allowing rapid absorption of calorie dense foods; releasing bioactive compounds which stimulate absorptive cells in the intestine to package and transport fat for absorption. Continuous presence of these microbes leads to over-nutrition and obesity.
To determine if microbes were required for digestion and absorption of fats, and assess the role of microbes involved in digestion and uptake of fats researchers studied model mice which were bred harboring no intestinal bacterial, germ free, and mice that were specific pathogen free. Germ free animals even when fed high fat diets were unable to digest or absorb fatty foods, and did not gain weight, instead their stool had elevated lipid levels. When germ free animals were introduced to microbes which contribute to digestion of fat they readily gained the ability to absorb lipids. SPF mice did gain weight on the high fat diet which boosted abundance of microbes in the small intestine including Clostridiaceae which impacts fat absorption, and Peptostreptococcaceae. Bacteriodacaea and Bifidobacteriacaea were found in decreased levels which are associated with leaness.
The way we eat on daily basis has impact on the abundance and types of bacteria found within the gut, which directly play imortantroles to influence metabolism and propensity to gain weight. Researchers say that preliminary results suggest use of pre or probiotics to enhance nutrient uptake for patients with malabsorption disorders such as Crohn’s disease would be beneficial.
Materials provided by University of Chicago Medical Center.
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Kristina Martinez-Guryn, Nathaniel Hubert, Katya Frazier, Saskia Urlass, Mark W. Musch, Patricia Ojeda, Joseph F. Pierre, Jun Miyoshi, Timothy J. Sontag, Candace M. Cham, Catherine A. Reardon, Vanessa Leone, Eugene B. Chang. Small Intestine Microbiota Regulate Host Digestive and Absorptive Adaptive Responses to Dietary Lipids. Cell Host & Microbe, 2018; 23 (4): 458 DOI: 10.1016/j.chom.2018.03.011