A sugary diet wrecks gut microbes — and their anti-obesity efforts.

A high-sugar diet unbalances the microbiome, so the body makes fewer of the gut immune cells that help to prevent metabolic disorders.​ An intricate relationship between diet, gut bacteria and immune cells helps to protect against obesity and other metabolic conditions, according to experiments in mice.​

Metabolic syndrome is a group of health conditions, such as high blood sugar levels, that collectively increase the risk of cardiovascular disease and diabetes. Yoshinaga Kawano at Columbia University in New York City and his colleagues found that in mice, certain gut bacteria help to prevent the disorders that make up metabolic syndrome by inducing a rise in levels of T helper 17 (TH17) cells. These immune cells, the authors found, reduce the gut’s absorption of lipids.​

A high-fat, high-sugar diet eliminated the helpful bacteria, but giving mice bacterial supplements prevented them from developing obesity and metabolic syndrome, even on the high-fat, high-sugar diet. A closer look at the ingredients in that diet revealed that its high sugar content fuelled the growth of Erysipelotrichaceae bacteria, which killed off the immune-regulating bacteria. Removing sugars from that diet prevented mice from developing obesity or metabolic syndrome, but only if the animals still had bacteria-induced TH17 cells.

Link to full article: ​​https://www.nature.com/articles/d41586-022-02775-9