A study of mice found that dietary sugar alters the gut microbiome, setting off a chain of events that leads to metabolic disease, pre-diabetes, and weight gain. The findings suggest that diet matters, but an optimal microbiome is equally important for the prevention of metabolic syndrome, diabetes, and obesity.

 

Diet alters microbiome

A Western-style high-fat, high-sugar diet can lead to obesity, metabolic syndrome, and diabetes, but how the diet kickstarts unhealthy changes in the body is unknown.

 

The gut microbiome is indispensable for an animal's nutrition, so Ivalyo Ivanov, PhD, associate professor of microbiology & immunology at Columbia University Vagelos College of Physicians and Surgeons, and his colleagues investigated the initial effects of the Western-style diet on the microbiome of mice.

 

After four weeks on the diet, the animals showed characteristics of metabolic syndrome, such as weight gain, insulin resistance, and glucose intolerance. And their microbiomes had changed dramatically, with the amount of segmented filamentous bacteria -- common in the gut microbiota of rodents, fish, and chickens -- falling sharply and other bacteria increasing in abundance.

 

Microbiome changes alter Th17 cells

The reduction in filamentous bacteria, the researchers found, was critical to the animals' health through its effect on Th17 immune cells. The drop in filamentous bacteria reduced the number of Th17 cells in the gut, and further experiments revealed that it's the Th17 cells that are necessary to prevent metabolic disease, diabetes, and weight gain.