Unhealthy Gut Bacteria Contribute to Diabetes Risk in African American Men

March 06, 2015

Unhealthy Gut Bacteria Contribute to Diabetes Risk in African American Men

     African American men at elevated risk for developing type 2 diabetes have fewer beneficial bacteria in their intestines and more harmful intestinal bacteria according to research presented by Dr. Irina Ciubotaru, an Endocrinologist at the University of Illinois at Chicago, at the ENDO 2015 meeting in San Diego.

"The 'signature' of the gut microbiota -- the relative abundance of various bacteria and other microbes in the digestive system -- could be another useful tool in assessing a person's risk for developing diabetes," said Dr Ciubotaru and her colleagues, including Dr. Elena Barengolts, professor of medicine in the UIC College of Medicine and chief of endocrinology at the Jesse Brown VA Medical Center. The team of collaborators found that a specific microbiota is associated with stable, normal blood glucose levels, while a different profile is associated with glucose levels that indicate pre-diabetes.
"The study provides additional reasons for physicians to recommend foods, such as prebiotics, which improve the growth and activity of helpful gut bacteria," said Dr Barengolts.

The gut microbiota helps digest food; fights infections; and plays an important role in keeping the immune system healthy. It is influenced by genetics, but more so by diet, stress and other environmental factors. Previous research has implicated an unhealthy or unbalanced microbiota as a contributing factor to metabolic disorders, including obesity and diabetes. The species that make up an individual's gut microbiota, as well as their abundance, can be identified by stool sample analysis.

The researchers determined the gut microbiotas of 116 African-American male veterans, age 45 to 75, participating in the D Vitamin Intervention in VA, or DIVA study. The aim of the DIVA study, which has 173 total participants and is funded by the Department of Veterans Affairs, is to determine if vitamin D supplementation can prevent diabetes in men with risk factors for developing the disease.

Participants were divided into four groups based on changes in their blood sugar levels as determined at the start and end of the one-year study. The groups included men whose glucose levels remained normal; those with stable levels indicative of pre-diabetes; those whose levels indicated a worsening of glucose control; and those whose levels improved. All the men provided stool samples for analysis of their gut microbiota.

Men whose blood sugar levels stayed normal over the year had more gut bacteria that are considered beneficial for metabolic health, whereas those who stayed pre-diabetic had fewer beneficial bacteria and more harmful bacteria. In addition, the group whose levels improved had more abundant and specific species of healthy bacteria--than the group that maintained normal blood sugar control throughout the year. The study suggests that differences in the gut microbiota already exist in pre-diabetes, Dr Barengolts said.

Based on other research her group has conducted and studies in animals, she speculated that the foods we eat affect our diabetes risk through our gut microbiota. If the mix of organisms in the intestinal tract is indeed responsible for the development of type 2 diabetes, she said, it may be possible to lower one's risk by changing the gut bacteria.

"If we can identify those with microbiota signatures indicative of pre-diabetes, and intervene with dietary changes or other interventions that we know boost populations of beneficial gut bacteria, we may be able to prevent the development of diabetes," said Dr Ciubotaru. The report is based on material provided by University of Illinois at Chicago.