SAN DIEGO — Fewer beneficial and more harmful intestinal bacteria appear to exist in African-American men at elevated risk for developing type 2 diabetes, according to a veterans’ study.

The research was presented at the ENDO 2015 meeting in San Diego.1

“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 study author Irina Ciubotaru, MD, PhD, of the University of Illinois at Chicago.

Elena Barengolts, MD, professor of medicine in the UIC College of Medicine and chief of endocrinology at the Jesse Brown VAMC was principal investigator for the study, which 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,” Barengolts noted.

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 DIVA study, which has 173 total participants, is trying to determine if vitamin D supplementation can prevent diabetes in men with risk factors for developing the disease.

For the study, 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 (non-pre-diabetic); 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. Those who stayed pre-diabetic, however, had fewer beneficial bacteria and more harmful bacteria. In addition, the group whose levels improved had more abundant Akkermansia — healthy bacteria — than the group that maintained normal blood sugar control throughout the year, the study pointed out.

Although the study found connections between composition of the gut microbiota and blood sugar control, Barengolts said further research is needed to confirm the findings and evaluate whether certain intestinal bacteria cause type 2 diabetes.

“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,” she added, “we may be able to prevent the development of diabetes.”

1Ciubotaru I, et. al. (2015 March) Significant differences in fecal microbioata are associated with various states of glucose tolerance in African-American male veterans. Presented at ENDO 2015. San Diego, CA.