The diversity of the three pounds of Intestinal bacteria that humans carry in their belly may explain why some of us are more likely to be obese than others, according to a recent study in Nature.
Danish researchers found for the first time that gut bacteria in 169 obese people was up to 40% less diverse than that in a group of 123 non-obese people. That discovery should change the way the way obesity and overweight, one of the most serious health problems of the 21stcentury, is treated.
Loss of microbial gene richness, or diversity, among intestinal bacteria was associated with several kinds of metabolic disorders and other health risks. For example, researchers found that those with poor diversity (low bacterial richness) not only had more body fat, they:
- were less healthy.
- were more resistant to insulin.
- were more likely to have high cholesterol and triglyceride levels.
- had increased levels of markers of inflammation.
- had increased levels of white blood cells.
It’s interesting to note that in the Danish study, people with low gut bacteria diversity—irrespective of their weight—were more prone to developing obesity-associated chronic diseases, such as diabetes, heart disease, and cancer. This increase risk is most likely due to the increase in insulin resistance and inflammation. In contrast, higher microbial gene diversity, or “high” bacterial richness, was linked with low inflammation and improved insulin sensitivity.
Boosting Gut Bacteria Diversity
Having poor intestinal bacteria diversity is not permanent. It can be improved with diet. For instance, eating fruits and vegetables that are high in fiber and polyphenolic compounds fosters increased bacterial richness and metabolic improvements.
After following a high-fiber, low-calorie diet, the people in the Danish study who had low diversity increased the richness of their gut bacteria. This was associated with a reduction in body fat and a decrease in their levels of cholesterol and inflammation markers, such as C-reactive protein.
Stopping The Obesity Epidemic
Too often people assume that obesity and overweight are caused by eating too much high-calorie food, especially food high in fat and sugar. True diet and exercise are critical, but this new research adds to the growing evidence that being overweight is not just a matter of calories in/calories out. Gut bacteria living at the interface between food and the intestine are critical players in weight gain, too.
With 35% of the world adult population aged over 20 being overweight and 11% being obese, I think it’s time to consider effective ways to alter the composition of the trillions of bacteria in the gut. After all, we now have proof that low gut bacteria richness fosters susceptibility not only to obesity but also to diabetes and cardiovascular disease.
Le Chatelier, E., Nielsen, T., Qin, J., Prifti, E., Hildebrand, F., Falony, G., et al. (2013). Richness of human gut microbiome correlates with metabolic markers. Nature, 500(7464), 541–546. doi:doi:10.1038/nature12506