Gut Bacteria May Be Key to Gastric Bypass' Effects

Gastric bypass surgery may help people lose weight by 

changing the make-up of bacteria living in the intestines, 

suggests a new study conducted in mice.

Scientists  discovered that performing gastric bypass surgery 

on mice altered the composition of the bacterial colony living 

in the animals' guts. Even when they did not perform the 

surgery, and just transferred the new bacterial colony into the 

intestines of mice, those mice lost weight.

Simply by colonizing mice with the altered microbial 

community, the mice were able to maintain a lower body fat, 

and lose weight -- about 20 percent as much as they would if 

they underwent surgery,said the researchers.

The study suggests that the specific effects of gastric bypass 

on the microbiota contribute to its ability to cause weight 

loss, and that finding ways to manipulate microbial 

populations to mimic those effects could become a valuable 

new tool to address obesity.

Another expert agreed that the gut is intricately tied to weight 

loss.

The gut is a key player in metabolism, and this makes it even 

more than ever an ideal target for interventions for treating 

metabolic diseases and obesity.

It may someday be possible to use medication or changes in 

diet to help people lose weight by changing the make-up of 

germs in the intestine. 

For many years, researchers thought they(bacteria) were a 

contaminant because we get them from the environment as 

we eat. But, scientists now understand that the bacteria play 

a role in the way the body processes food. We eat for us, 

but we also eat for them [bacteria].

Scientists have suspected that gastric bypass procedures, 

which funnel food away from the stomach, change the 

make-up of bacteria in the gut.

 The bypass, by shortening the digestive tract, may actually 

change "the chemistry of the intestinal environment where 

these bugs live."

Scientists note that research with animals often fails to 

provide similar results in humans.

 -- the transfer of germs from one mouse to another -- will be 

a challenge in humans, said a researcher.

"The transfers were done to germ-free animals, but humans 

are not germ-free, and it will be difficult to take a pill and get 

germs to the right location [in the digestive system],said a 

researcher.