In this study, researchers analyzed that eating the right dietary fibers may rebalance the gut microbiome and lead to reduced blood sugar and body weight, and may pave the way for a new nutritional approach to preventing and managing type 2 diabetes. The study was published in Gut.

A select "guild" of gut bacteria responsible for the benefits of high-fiber diets in type 2 diabetes has been identified in a study in which those patients on the high-fiber diet showed improved control of HbA1c. The specific bacteria thought to be useful produce short-chain fatty acids (SCFAs).

By manipulating the gut microbiota to manage type 2 diabetes and potentially other dysbiosis-related diseases write the authors led by Liping Zhao. A whole-grain diet failed to alter insulin sensitivity and the gut microbiome in healthy individuals at risk for development of metabolic syndrome. But the high-fiber diet did lead to lower body weight and less systemic low-grade inflammation.

Certain Fibers Could Become Part of the Treatment for Type 2 Diabetes

In their paper, Zhao and colleagues explain that gut microbes play a range of roles in response to food intake, and they suggest that chronic diseases, such as type 2 diabetes, may in part result from a deficiency in SCFA production from carbohydrate fermentation in the gut.

Prior clinical trials have shown that increased intake of nondigestible but fermentable carbohydrates (dietary fibers) helps alleviate type 2 diabetes, but treatment responses vary considerably. The authors note that improved understanding of how gut bacteria respond, both as individual species and via interactions with each other, may improve clinical outcomes of dietary interventions.

In this study, patients with type 2 diabetes were randomly assigned to either a control group, in which they received usual care comprising patient education and dietary recommendations (n = 16), or the high-fiber diet treatment group, in which they were prescribed a diet composed of whole grains, traditional Chinese medicinal foods, and prebiotics (n = 27).

The researchers characterized the dynamics of the gut microbiota and its effect on patients' glucose levels, including cataloging bacterial genes to see how the increased dietary fibers altered the overall composition of the gut microbiota. Specifically, they examined the genes involved in the production of glucose metabolites.

Of 141 strains of SCFA-producing gut bacteria identified, only 15 were promoted by consumption of the high-fiber diet, and these are the ones most likely to be involved in driving the health benefits seen. These 15 formed the so-called guild that boosts deficient SCFA production (mainly butyrate and acetate) from the gut ecosystem, say the researchers.

The author concludes the whole grain consumption has beneficial effects on blood markers of subclinical inflammation in adults at risk of developing metabolic syndrome, and higher intake of whole grains should be encouraged in those at risk of inflammation-related diseases.