Western Diet Harms Gut Flora
FIRENZE, Italy—Typical Western diets of sugary, fatty foods may promote the risk of asthma, allergies and other inflammatory diseases by affecting the way gut bacteria functions, according to a new study from the University of Florence (Proc Natl Acad Sci USA. 2010 Aug 2).
Researchers, led by Carlotta De Filippoa, compared the fecal bacteria of 15 European children (EU) to that of 14 children from a rural African village of Burkina Faso (BF), where the diet, high in fiber content, is similar to that of early human settlements at the time of the birth of agriculture.
They found significant differences in gut bacteria between the two groups. BF children showed a significant enrichment in Bacteroidetes and depletion in Firmicutes (P<0.001). Bacteroidetes and are plant-digesting genes,
The gut of the BF children contained an abundance of bacteria from the genus Prevotella and Xylanibacter, which are known to contain a set of bacterial genes that digest plant cellulose. They found Firmicutes was completely lacking in the EU children. Other studies have shown the intestinal flora of obese humans and mice have a lower percentage of Bacteroidetes and relatively more bacteria from the Firmicutes family.
In addition, they found significantly more short-chain fatty acids (SCFAs) (P<0.001) in BF than in EU children. Studies have shown SCFAs to be associated with lower levels of allergies and inflammation.
Also, the harmful bacteria Enterobacteriaceae (Shigella and Escherichia) were significantly underrepresented in BF than in EU children (P<0.05). These bacteria are associated with food-borne illnesses and diarrhea.
With this data, they hypothesized gut microbiota coevolved with the polysaccharide-rich diet of BF individuals, allowing them to maximize energy intake from fibers, while also protecting them from inflammations and noninfectious colonic diseases. They concluded by noting the importance of maintaining the microbial diversity from ancient rural communities worldwide to help reduce inflammation and disease.