The largest and most ethnically and geographically comprehensive investigation to date of the gut microbiome of people with type 2 diabetes (T2D), prediabetes, and healthy glucose status has found that specific viruses and genetic variants within bacteria correspond with changes in gut microbiome function and T2D risk. Results of the study — which represents a collaboration across Brigham and Women’s Hospital, the Broad Institute of MIT and Harvard, and Harvard T.H. Chan School of Public Health — are published in Nature Medicine.

"The microbiome is highly variable across different geographic locations and racial and ethnic groups. If you only study a small, homogeneous population, you will probably miss something," said co-corresponding author Daniel (Dong) Wang, an assistant professor of medicine at Brigham and Women's Hospital and of nutrition at Harvard Chan School, and an associate member of Broad's Infectious Disease and Microbiome Program (IDMP). "Our study is by far the largest and most diverse study of its kind."

"The gut microbiome's relationship to complex, chronic, heterogeneous diseases like T2D is quite subtle," said co-corresponding author Curtis Huttenhower, a professor of biostatistics and immunology and infectious Diseases at Harvard Chan School and also an associate member of Broad's IDMP. "Much like studies of large human populations have been crucial for understanding human genetic variation, large and diverse populations are necessary — and increasingly feasible — for detailed microbiome variation studies as well."

T2D affects approximately 537 million people worldwide. In T2D, the body gradually loses its ability to regulate blood sugar effectively. Research over the last decade has linked changes in the gut microbiome — the collection of bacteria, fungi, and viruses that inhabit our intestines — to the development of T2D. However, prior studies of the gut microbiome and its role in T2D have been too small and varied in study design to draw significant conclusions. 

Source: https://www.broadinstitute.org/news/gut-microbiome-changes-fuel-increased-risk-type-2-diabetes