A Mayo Clinic researcher, and collaborators, have shown that an individual's diet and genomic makeup interact to determine which microbes exist and how they act in the host intestine. The study was modeled in germ-free knockout mice to mimic a genetic condition that affects 1 in 5 humans and increases the risk for digestive diseases. You can read the full findings in the Proceedings of the National Academy of Sciences.
"Our data show that factors in the differences in a host's genetic makeup — in this case genes that affect carbohydrates in the gut — interact with the type of food eaten. That combination determines the composition and function of resident microbes," says Purna Kashyap, M.B.B.S., a Mayo Clinic gastroenterologist and first author of the study. He also collaborates in the Microbiome Program of the Mayo Clinic Center for Individualized Medicine.
Around 20% of humans lack the gene that encodes proteins for processing fucose, a sugar in the intestinal mucus. Many bacteria are adept at utilizing carbohydrates such as fucose, which are abundant in the gut. Confronted with diets that have little or no complex plant sugars, these bacteria are forced to change their function, especially in hosts that lack fucose. This was seen with the altered metabolic gene expression of one of the key microbes in the gut — Bacteroides thetaiotaomicron. Changes in microbial function may, in turn, foster a "digestive landscape" that can promote inflammatory conditions such as Crohn's disease.
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