A new study suggests your gut bacteria could show whether you have type 2 diabetes. After analyzing some 60,000 bacterial markers in people with and without the disease, scientists in China and Europe conclude there is something recognizably different in the gut bacteria of people with type 2 diabetes.

They write about their findings in a paper published online in Nature on 26 September.

The study is a good example of how researchers, in this case from the University of Copenhagen in Denmark and the Beijing Genomics Institute (BGI) in China, are making huge progress in “metagenomics”, an exciting new field that looks for DNA patterns across colonies as opposed to within individual organisms.

It’s important to note that while the study indicates a number of ways gut bacteria in a person with type 2 diabetes are different from those of healthy people without the disease, it does not prove they actually cause disease: they could just be reflecting the fact the person has type 2 diabetes.

The Danish members of the team are now planning to answer this question:

“We are going to transplant gut bacteria from people that suffer from type 2 diabetes into mice and examine whether the mice then develop diabetes,” professor Oluf Borbye Pedersen from the University of Copenhagen and co-leader of the study, told the press.

Recent years have seen a rapid rise in the number of people diagnosed with type 2 diabetes, and scientists believe there are just as many undiagnosed people with the illness who don’t realize they have it.

We carry around 1.5 kg of bacteria in our intestines. These gut microbiota normally live in sensitive equilibrium with our bodies, helping us do vital things like ferment and digest food. If this equilibrium is upset, our health suffers.

Now, with this new study, scientists are suggesting it may be possible to see if a person has type 2 diabetes earlier and faster than current methods by looking for clear biological markers in their gut bacteria.

“We have demonstrated that people with type 2 diabetes have a high level of pathogens in their intestines,” says professor Jun Wang, another study co-leader who is also from the University of Copenhagen.

Wang and colleagues also discovered that people with type 2 diabetes have a more hostile bacterial environment in their gut, which can increase resistance to different medicines.

For their study they developed a particular protocol for using a “metagenome-wide association study (MGWAS)”, to sequence the DNA of gut bacteria in 345 people from China, 171 of whom had been diagnosed with type 2 diabetes.

In their paper they describe how they “identified and validated approximately 60,000 type-2-diabetes-associated markers” and also linked some together so they can be analyzed in taxonomic groups.

The analysis showed the participants with type 2 diabetes had more imbalances in their gut bacteria (“a moderate degree of gut microbial dysbiosis”), lower levels of a group of bacteria called “universal butyrate-producing bacteria”, and higher levels of “opportunistic pathogens”, plus other differences.

The team double-checked the findings in another 23 individuals and found the “gut microbial markers might be useful for classifying type 2 diabetes”.

Other similar studies of people with type 2 diabetes in Denmark have also found significant imbalances in the mix and behavior of their gut bacteria.

Written by Catharine Paddock PhD