The findings form part of the EU-funded MetaHIT project that last year reported the discovery of three distinct types of gut bacteria in people. The new data, produced by researchers in Europe and China sheds new light on future research and disease assessment for diabetes by revealing that people with the condition have higher levels of certain pathogenic bacteria.
The novel meta-genomic study reveals a large association between the landscape of the human gut microbiota and type 2 diabetes – suggesting that the make-up of our gut microflora could have a large impact on the development of the condition.
“We have identified that patients with type 2 diabetes in fact have an imbalance in their gut bacteria,” said Professor Oluf Borbye Pedersen, of the University of Copenhagen – a senior research on the project.
“In other words they appear to have an excess of harmful or bad bacterial types and on the other hand they suffer from a lack of health promoting good bacterial types.”
Led by Professor Karsten Kristiansen from the University of Copenhagen and Professor Jun Wang from the Beijing Genomics Institute (BGI), China, the research team suggests that their work lays an ‘important foundation’ for comprehensively understanding the genetic characteristics of gut bacteria and their relationship to type 2 diabetes.
"The European and Chinese working on the MetaHIT project were able to make important new discoveries about the relationship between intestinal bacteria and health,” explained Kristiansen. “The new discovery indicates a possible connection between type 2 diabetes and the intestinal bacteria in Chinese people."
However Kristiansen stressed that it is important to point out that the discovery currently only demonstrates a correlation between gut bacteria profiles and the condition: “The big question now is whether the changes in gut bacteria can affect the development of type 2 diabetes or whether the changes simply reflect that the person is suffering from type 2 diabetes," she said.
“The 1,000 dollar question here is what is the cause and what is the consequence,” said Pedersen. “To be honest, we don’t know.”
In the new study, scientists examined the intestinal bacteria of 345 people from China, of which 171 had type 2 diabetes. The team managed to identify clear biological indicators that someday could be used in methods that provide faster and earlier diagnosis of type 2 diabetes, and may even lead to modifications and treatments.
The research demonstrated that people with type 2 diabetes have a more hostile bacterial environment in their intestines, which can increase resistance to different medicines.
A future study is now planned to examine whether intestinal bacteria is already abnormal in people that are deemed to be at risk of developing diabetes, in addition to animal research that will test if the bacterial changes are the root cause of diabetes.
"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," said Pedersen.
Published online ahead of print, doi: 10.1038/nature11450
“A metagenome-wide association study of gut microbiota in type 2 diabetes”
Authors: Junjie Qin, Yingrui Li, Zhiming Cai, Shenghui Li, Jianfeng Zhu, Fan Zhang, et al