Enterotypes can explain efficiency of uptake of nutrients and medicines
Every person’s intestinal system falls into one of three clearly distinguishable types of gut microbiota, comparable to blood types. These types are not related to race, native country or diet, according to a new metagenomics study by an international consortium of scientists (MetaHIT
) including Jeroen Raes, of VIB and Vrije Universiteit Brussel. Metagenomics is the study of the genetic material of complete ecosystems, in this case the human gut. Nature is publishing the results.
“The three gut types can explain why the uptake of medicines and nutrients varies from person to person,” says bioinformatician Jeroen Raes of the VIB and Vrije Universiteit Brussel, one of the two lead researchers in the study. “This knowledge could form the basis of personalized therapies. Treatments and doses could be determined on the basis of the gut type of the patient.”
Improved knowledge of the gut types could also lead to other medical applications, such as the early diagnosis of intestinal cancer, Crohn’s disease and the adverse effects of obesity.
Three types of gut microbiota
The types of gut microbiota (called enterotypes) can be classified into three large, clearly distinguishable groups: Bacteroides, Prevotella and Ruminococcus. They are named for the bacteria that dominate the intestines of the respective groups. It is still unclear whether people can change from one group to another during their lives.
Bacteria form strong ecosystem in the gut
Scientists do not yet have a conclusive explanation for the existence of the types of gut microbiota, but all the evidence indicates that only a limited number of stable biotic communities are possible in our intestines. In this way they are comparable to other ecosystems in nature, such as forests, tundra, tropical jungles, savannas and others. Ecosystems have a tendency to evolve towards a stable equilibrium, with certain species that become dominant and others that occupy niches. This also appears to apply to our intestines.
Relationship with BMI
The study shows a connection between human characteristics and gut microbiota. For instance, correlations were found between the Body Mass Index (BMI) and the strains of bacteria in the gut. The more efficiently the bacteria can extract energy from the food, the greater the chance that the person has a high BMI (and therefore struggles with obesity). The researchers found that the presence of certain bacterial genes could serve as diagnostic and/or predictive markers for obesity. This finding is currently undergoing further testing in a clinical study in a group of over 100 individuals. This involves examining the DNA of the complete gut microbiome of those.
Differences in vitamin production
It is notable that the vitamin production between the different groups varies strongly. People that belong to the Bacteroides group have more gut bacteria that produce vitamins C, B2, B5 and H. The Prevotella group showed higher numbers of B1 and folic acid-producing flora.
Crucial role of gut microbiota
An estimated 100,000 billion individual bacteria live in our intestines. They form our gut microbiota. These bacteria play a crucial role in protecting our health. They help to covert food into energy and protect us against attacks by pathogens. In exchange for these benefits, our bodies provide the bacteria with habitat and nutrition.
Metagenomics as a study method
In the past, the study of gut microflora was very difficult. The problem was that most gut bacteria cannot be cultivated in a lab and only survive in the intestines. A different approach is now used. Instead of cultivating the bacteria, the genetic information (DNA) of all the bacteria is studied together (metagenomics). This generates a vast amount of data that is analyzed using powerful computers.
Enterotypes of the human gut microbiome, Manimozhiyan Arumugam, Jeroen Raes, et al, Nature, doi:10.1038/nature09944
This research was conducted by Jeroen Raes of the VIB Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel VIB and Manimozhiyan Arumugam of the European Molecular Biology Laboratory.
The research is being done as part of the MetaHIT (METAgenomics of the Human Intestinal Tract www.metahit.eu
) collaboration, a scientific project that aims to understand the effect of gut bacteria on our health. It is a collaboration of European and Chinese research institutions and industrial and pharmaceutical companies. MetaHIT receives support from the European Commission within the Seventh Framework Programme. This research was led by Peer Bork (EMBL) and Dusko Ehrlich (INRA).
The enterotypes paper attracted quite some media coverage. Below you find a selection of articles and interviews about this research: