Our gut bacteria may pull double duty as a fortune teller when it comes to type 2 diabetes, a new study published Wednesday in Genome Medicine suggests.

The study authors decided to expand beyond earlier research showing that the environment of bacteria in the gut — or microbiome — is fundamentally different in people with diabetes when compared to non-diabetics. They did so by analyzing the medical records and fecal samples of 20 identical healthy Korean twins aged 30 to 48. Though none of the twins were clinically diabetic, they each had varying levels of risk, and the same sort of changes seen in the microbiomes of diabetic patients were found in those twins who were pre-diabetic, even if they showed no detectable symptoms at the time. These findings signal the possibility of someday using our gut bacteria as an early warning system for diabetes.

"Previous studies of the microbiome in (type 2 diabetics) have examined extreme cases — individuals with established disease as compared to particularly healthy individuals — in order to identify imbalances in the gut microbiota linked to the disease. We set out to determine whether these microbial changes occur early on, in tandem with preclinical variation in typical (type 2 diabetic) biomarkers such as BMI," study author Curtis Huttenhower said in a statement. "It was also possible for us to take into account genetic contributions and temporal variation in the microbiome thanks to the participation of a group of twins who generously provided multiple samples over time."    

The participants were enrolled in South Korea’s Healthy Twin Study, which first began in 2005. For 16 of the twins, the fecal samples were given at least two different points in time, one at the start and another 12 to 44 months later — the remaining four gave only one sample.

Aside from changes to their gut bacteria, Huttenhower and his colleagues were also able to spot a particular quirk in their microbiomes. Though a pair of twins largely had the same species of bacteria, the specific strains differed between the two. "It suggests that twins are initially colonized by the same bugs in infancy — due perhaps to shared environment or genetics — and then retain those organisms long enough to begin to diverge through short-term evolution."explained Huttenhower."“If true, this can be studied directly in larger twin cohorts, and it would help us understand how the microbiome develops beyond diabetes alone in a wide variety of conditions."

As Huttenhower hints, though, it’s still far too early to declare anything definitive from their findings, especially given the small scale of the study.

While scientists are confident that imbalances in gut microbiota can be a factor in a variety of medical conditions like obesity, they’re largely in the dark as to the specifics. For instance, it might be the case certain changes are perfectly harmless and only coincide with the development of a chronic disease rather than help cause it. And even if we find the smoking gun that connects a particular alteration in the gut microbiome to a condition, we might be hard pressed to understand why.

Still, the researchers are optimistic their results are a step in the right direction toward accomplishing that very goal, and they hope larger twin studies will be able to adopt their methods.

Source: Huttenhower C, et al Genome Medicine. 2016.