Obesity can be caused by alterations to gut microflora.
In humans, obese people have a lower proportion of bacteroidetes and higher proportion of firmicutes in the intestine. Upon restriction of calories, the proportion of firmicutes decreased, and bacteroidetes increased.

This is only founded on correlated statistics, thus it may be related to obesity.

In mice, it is observed that conventionally reared mice have a higher fat concentration to gnotobiotic mice. Transplantation of microbial community from conventional mice into gnotobiotic mice increases fat content. This establishes a cause and effect relationship.

The Firmicutes:bacteroidetes ratio stands true in mice. Inoculation of GF mice with obese mouse microflora results in greater fat content than inoculation with conventional mouse microflora.

Hypothesis: the bacterial community in obese individuals may be more efficient in utilizing otherwise indigestible polysaccharides.

This is not definitive, as studies among humans have been small and more research is to be done.

	Created by Austin Davies about 8 years ago

Lecture 12 - medical micro

Impact of symbiosis on health and disease