Then and now…

In the early 1900’s, scientists discovered that each person belongs to one of four blood types. Now they have discovered a new way to classify people – by bacteria! In the future, when you walk into a hospital, you may be asked your blood type, allergies, and gut type.

Blood type, meet bug type

All human beings are host to thousands of different species of microbes. A group of scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, report that there are three distinct ecosystems in the human gut – 3 different gut types. And it may not stop there. Some scientists suggest there may be as many as 7 general digestive categories.

“It’s an important advance,” according to Rob Knight, a biologist at the University of Colorado. “It’s the first indication that human gut ecosystems may fall into distinct types.”

Why is gut type so important?

Different digestive types probably determine why different people respond to diet, nutritional supplements and drugs differently!  

We all have bacteria in our gut that help digest food, produce essential amino acids, break down toxins, produce vitamins and form a barrier against invaders. However, the composition of that microbial community – the relative numbers of different kinds of bacteria – varies from person to person.

These studies showed different regions of the digestive system are home to different combinations of bacteria species. From one person to another, scientists found tremendous variations. Many of the bacteria species that lived in one person’s mouth, for example, were missing from another’s. However, from the variations, a pattern emerged. “We found that the combination of microbes in the human intestine isn’t random,” states Peer Bork, who led the study at EMBL.

Bork and his colleagues found that human test subjects could be divided into three groups, based on which species of bacteria occurred in high numbers in their gut. Each person could be said to have one of three gut types, or enterotypes.

The discovery of the blood types A, B, AB and O had a major effect on how doctors practice medicine. They could limit the chance that a patient’s body would reject a blood transfusion by making sure the donated blood was of a matching type.

Whatever the cause of the different enterotypes, these gut types may also effect how doctors practice medicine and on our overall health. Gut microbes aid in food digestion and synthesize vitamins, using enzymes our own cells cannot make. So, our awareness of gut types could have profound effects.

The discovery of enterotypes could someday lead to a vast array of new medical applications – these are down the road. However, “Some things are pretty obvious already,” says Dr. Bork. Doctors might be able to tailor diets or drug prescriptions to suit enterotypes. For example, Dr. Bork and his colleagues found that each of the digestive types makes a unique balance of enzymes.

• A Gut type 1 – produces more enzymes for making vitamin B7 (biotin) and had high levels of bacteria called Bacteroides.

• A Gut type 2 – produces more enzymes for vitamin B1 (thiamine). Bacteroides were relatively rare, while the genus Prevotella was unusually common.

A study, published in Nature, also uncovered microbial genetic markers that could one day be used to help diagnose and predict outcomes for diseases like colorectal cancer. Information about a person’s gut type could help inform treatment.

“The fact that there are bacterial genes associated with traits like age and weight indicates that there may also be markers for traits like obesity or diseases like colorectal cancer,” Bork says, “which could have implications for diagnosis and prognosis.”

If this proves to be the case, when diagnosing or assessing the likelihood of a patient contracting a particular disease, doctors could look for clues not only in the patient’s body but also in the bacteria that live in it. After diagnosis, treatment could be adapted to the patient’s gut type to ensure the best results.

Or, Bork speculates, doctors might be able to use enterotypes to find alternatives to antibiotics, which are becoming increasingly ineffective. Instead of trying to wipe out disease-causing bacteria that have disrupted the ecological balance of the gut, they could try to provide reinforcements for the good bacteria. “You’d try to restore the type you had before.”

What does this research mean for us?

We plan to keep on top of this developing research. The awareness of gut types may lead to more highly tuned use of nutritional supplements. We look forward to sharing what we learn in the pursuit of optimal health.

(Excerpts for the above story are from materials provided by the European Molecular Biology Laboratory, via EurekAlert!, a service of AAAS.  Note: Materials may be abbreviated for length. For further information, please contact the source cited above.)

References:

Arumugam, Raes, Pelletier, Paslier, et. al., Enterotypes of the human gut microbiome. Nature, Volume: 473, Pages: 174–180, Date published: 12 May 2011,  DOI: doi:10.1038/nature09944

Ruth E. Ley, Daniel A. Peterson and Jeffrey I. Gordon,  Ecological and Evolutionary Forces Shaping Microbial Diversity in the Human Intestine, Center for Genome Sciences, Washington University School of Medicine, St. Louis, MO 63108, USA.