In two new studies on 28,000 individuals, researchers can show that genetic variants in 11 regions of the human genome have a clear influence on which bacteria are in the gut and what they do there. Only two genetic regions were previously known. Some of the new genetic variants can be linked to an increased risk of gluten intolerance, hemorrhoids, and CVD.
The gut microbiome has become a hot research area in recent years because of its significant role in health and disease. However, the extent to which genes determine which bacteria are present in the gut has been unclear. Until now, it has only been possible to link a few genetic variants to the composition of the gut microbiome with certainty.
Now, in two coordinated international studies, researchers have conducted the most comprehensive investigation to date of the link between the genome and the gut microbiome. The researchers analyzed genetic data and gut bacteria from over 28,000 individuals, appreciating that each individual carries hundreds of different bacteria species.
The analysis identified 11 genetic regions that affect both the bacteria present in the gut and the roles they play. Several of the genes are associated with fundamental processes in the gastrointestinal tract such as how nutrients are absorbed and how the body reacts to the bacteria.
“We have learned a lot about the role played by genetics in the gut microbiome. Several of the genetic connections that we found have to do with very specific biological mechanisms. These concern, for instance, which molecules are present on the surface of gut cells and are thereby available as food for bacteria. They also relate to the way in which the gut reacts to molecules produced by bacteria,” says Tove Fall, DVM, PhD, a professor of molecular epidemiology at Uppsala University, who is responsible for one of the studies.
The researchers also saw clear connections between some of the genetic variants and several diseases. The diseases investigated had been previously linked with the gut microbiome.
“We saw that some of these genetic variants were linked to the risk of gluten intolerance, hemorrhoids, and CVD. This suggests that changes in the composition of intestinal bacteria could provide a way to better understand how genetic risks affect health,” says Claes Ohlsson, MD, PhD, a professor at the University of Gothenburg, who coauthored the other study.
The biobanks that the researchers have built up are among the largest in the world for gut microbiome.
“Given that many aspects of our health are linked to the gut microbiome, we naturally want our research to contribute to better ways of preventing and treating diseases by paying attention to the interaction between genes, gut biology, and the microbiome,” Fall says.
— Source: Uppsala University