Humans have just three types of gut bacteria populations
4 May 2011
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 study on human microbe genetics published in
The study was conducted by the European Metagenomics of the Human
Intestinal Tract (MetaHIT) Consortium. The consortium consists of 13
partners from academia and industry, from eight countries. It is
funded by the European Commission under the 7th FP programme. A
similar project in the US, the Human Microbiome Project, is
cataloguing the bacteria found in the nose, mouth, skin, gut, and
urinary and genital tracts.
The MetaHIT consortium published in March 2010 the first
comprehensive catalog of human intestinal bacterial genes, dubbed
our second genome. It was found that the gut bacteria encode 150
times as many genes as our own genome and that each individual
harbours some 170 bacterial species out of a total of about 1000
that are predominant in the gut. Most of these species are common to
many individuals, showing that we are all rather similar.
The current study has refined this view. A bioinformatic analysis at
the European Microbiology Lab (EMBL) showed that human populations
are split into three groups by the particular combinations of
bacterial species they harbor, independently of the geographic
origin, health status (obesity or inflammatory bowel disease) or
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
“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 Department of Molecular and Cellular
Interactions 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.”
The research used three different study populations. One included 39
individuals from three continents (Danish, French, Italians and
Spaniards from Europe; Japanese and Americans), another comprised 85
Danes and the last 154 Americans. The same three enterotypes were
observed with all.
In parallel, bacterial genes that can be used as biomarkers for
disease and age have also been found. This indicates that the
bacterial communities from our gut not only divide human populations
in large groups but can also signal the health status of an
Enterotypes will impact human biology, which will have to explain
their existence and the effects they have on humans. Enterotypes
will impact medicine and nutrition, by allowing the grouping of
individuals and determining their particular needs more efficiently.
Furthermore, gut microbial populations appear to contain novel and
promising biomarkers, which will impact detection and possibly
treatment of chronic diseases such as obesity and its complications
(metabolic syndrome, diabetes and cardiovascular pathologies).
The researchers foresee development of personalized and preventative
medicine and nutrition based on gut microbial populations, leading
to the overall improvement of human health and wellbeing.
1. Arumugam A, et al. Enterotypes of the human gut
microbiome. Nature (2011) doi:10.1038/nature09944.
2. Gut study divides people into three types. Nature. News.
3. The MetaHIT website: