Gastric bypass surgery is the commonest form of bariatric surgery. It is a procedure aimed at curing obesity by short circuiting the small intestine. There are around 113,000 bariatric operations in America every year. The physical change to the patients gut, with this kind of surgery, is only part of the story. Because the bacterial balance within the patient is also changed significantly.
A new study in mice, published in â€˜Science Translational Medicineâ€™, raises an interesting avenue of investigation to use bacteria rather than surgery to help the obese.
The conclusion of the study is this:
Â “It may not be that we will have a magic pill that will work for everyone who’s slightly overweight. But if we can, at a minimum, provide some alternative to gastric bypass surgery that produces similar effects, it would be a major advance. We need to learn a good deal more about the mechanisms by which a microbial population changed by gastric bypass exert its effects, and then we need to learn if we can produce these effects – either the microbial changes or the associated metabolic changes — without surgery. The ability to achieve even some of these effects without surgery would give us an entirely new way to treat the critical problem of obesity, one that could help patients unable or unwilling to have surgery.”
When alternate microbes were implanted into sterile mice, and the mice did not have bariatric surgery, those creatures lost significant body mass rapidly. The lead researcher describes the experimental outcomes thus:
Â “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.”
In the research, gastric bypass surgery was done on a number obese mice too. They were monitored not just for body mass changes but also for metabolic changes and bacterial levels and make-up in their guts. Control group comparisons were made with groups of mice that were also obese and thatÂ had â€˜placeboâ€™ surgery, and another group that had placebo surgery but were also on a strict calorie regime.
The experiment showed the mice that had the surgery reduced their body mass by 30% and had a changed bacterial makeup in their faeces. The control group mice without the diet, regained their lost weight in just 3 weeks. The conclusion is clear that it is the surgery that changes the bacterial status of the gut. In an extension to the experiment, normal weight, sterile animals were given bacteria from the three experimental groups. The animals who had bacteria from the mice that had gastric bypass were the only ones to lose weight and body mass. Even though they were not on a calorie controlled special diet.
The good news is that gastric bypass surgery doesnâ€™t just tackle obesity in one way. It is not yet known how the bacterial changes work or even come about, but it definitely boosts the physical shrinking of the stomach.