Does the microbacteria in your gut play a role in obesity?

Obesity is a fairly recent disease that most people have been blaming on the food they eat and on the lack of physical activity.  Only recently have scientists thought about the role the Human Microbiome plays in weight.  Microbacteria colonies were studied in mice and they found that mice receiving microbiota from an obese mouse gained more weight in a two week period than mice receiving the lean microbes.  From gene sequencing of the microbiota, researchers found that there was an "enrichment in genes involved in energy extraction from food in the obese host's microbiome relative to that of the lean host's microbiome."
Fecal samples were taken from 154 participants at an initial point and then again two months later.  Researchers found that participants with a lower microbacterial diversity were obese.  From the mouse and human study researchers learned that the microbacteria associated with obesity were involved with carbohydrate and lipid metabolism.  Researchers have also begun to study the diversity of microbacteria in other parts of the body like saliva.  Since microbacteria live in saliva and play an initial role in the breakdown of food, they wanted to test if there was a difference there too.  They found that the bacteria, Selenomonas, was only found in overweight people.
The gut communicates with the endocrine system and tells it what to do.  The microbacteria also regulate the gut hormones directly.  A study done on patients after gastric bypass surgery showed that patients who were given probiotics lost weight faster than patients not given probiotics.  This supports the idea that "gut bacteria may be modulating gut hormones."  Since many different studies were done the next step in this research is to standardize it and to use the same approach.




http://www.medscape.com/viewarticle/714569