healthHealth and Medicine

Weight Loss Surgery May Alter Gut Microbes To Help Keep Fighting Obesity


Jonathan O'Callaghan

Senior Staff Writer

1730 Weight Loss Surgery May Alter Gut Microbes To Help Keep Fighting Obesity
Gastric band surgery may have some hidden benefits. corbac40/Shutterstock

Weight loss surgery, or bariatric surgery, may not just help you shed the pounds in the short-term – it may actually affect your body’s collection of microbes and help stave off obesity in the long-term.

That’s according to research that investigated the effects of weight loss surgery after almost a decade. The team from the University of Gothenburg in Sweden studied 14 women who had undergone two forms of surgery nine years previously, Roux-en-Y gastric bypass and vertical banded gastroplasty. Both were found to alter the body’s microbiome.


In the research, published in the journal Cell Metabolism, microbes from the stool samples of women who underwent these surgeries were transplanted into specially bred “germ-free” mice that were devoid of any gut bacteria. Microbes from a separate group of obese women who had not undergone bariatric surgery were also transplanted into similar mice via the same method.

It was found that those mice given the microbes from the women who had surgery gained less weight than the other mice. While both gained weight following the transplant, the mice given the post-surgery microbes from Roux-en-Y and vertical banded gastroplasty patients gained 43% and 26% less fat respectively than the control group. This may have been due to the slimmer mice burning fewer carbohydrates and more fat than the control group, but the exact microbes at play are not yet known.

"Our findings are important in light of the growing epidemic of obesity and associated diseases," said Fredrik Bäckhed of the University of Gothenburg, who led the research, in a statement. "Since surgery always confers a risk, it is critical to identify non-surgical strategies. One potential strategy would be to devise novel probiotics based on our findings that can be supplied to obese individuals."

The findings suggest that the success of bariatric surgery – which includes reducing the size of a stomach with a gastric band or removing part of the stomach – may in part be due to this lesser-known microbiome effect, rather than just the surgery itself. This means that, in future, it might be easier and more beneficial to treat obesity by transplanting these weight-loss-associated microbes, rather than performing the complicated, expensive and occasionally risky procedures.


The problem now will be to work out which of the 1,000 types of microbes in our intestines are actually responsible for this apparent effect. If that can be narrowed down, it could have huge implications for treating obesity in future.


healthHealth and Medicine
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  • microbiome