High-fiber diet key to prevent gut infection even in lean people: Study

Obese mice followed two high-fat (60% and 45% fat), low-fiber diets. All of the animals developed AIEC expansion in the colon. The mice on the 60% fat diet had a higher body mass than those eating the 45% fat chow, but there was no significant difference in the amount of AIEC (AIEC burden) in their systems. "These data suggested that an aspect of diet composition rather than the magnitude of host obesity was sufficient to promote intestinal AIEC expansion," the researchers wrote.

The research team fed lean mice a high-fat diet on a short-term basis before significant obesity occurred to explore the effect of diet on AIEC burden. After the animals were exposed to AIEC, the lean mice eating the high-fat diet had more AIEC expansion than the controls (lean mice on a normal diet). These results "indicate that diet can regulate AIEC infectious burden independent of changes in body mass leading to obesity," the researchers wrote. Finally, the research team found that mice on a low-fat, low-fiber diet had higher AIEC burden than those eating a normal diet, suggesting that dietary fat was not the key ingredient, but "ingestion of lower dietary fiber is sufficient to promote expansion of AIEC throughout the gut."

One takeaway from this study is that people who are leaner may have similar risks of gut infection if they don't eat enough fiber. "Our data show that dietary fiber is a standalone factor," the researchers wrote.