For several years now, researchers have been building on a series of studies that have displayed links between non-invasive, deep Transcranial Magnetic Stimulation (dTMS) and reduced food cravings. Now, for the first time, research has shown that dTMS can fundamentally alter the composition of gut microbiota, resulting in both weight loss and general improvements in other metabolic and hormonal factors.

Transcranial Magnetic Stimulation has shown promise in recent years for a variety of applications, from boosting memory function to treating migraines. The technique involves firing magnetic pulses into particular regions of the brain to alter the activity of certain neurons. The process is currently approved for use in the United States to treat major depression.

Following on from studies that showed how an imbalance in gut bacteria altered the brain signals for appetite, a team at the IRCCS Policlinico San Donato and University of Milan set out to examine how dTMS could effect the composition of a subject's gut microbiota.

The study involved 14 subjects split into two groups. One group received 15 dTMS sessions over five weeks, targeting the insula and prefrontal cortex, while the other group was the control, receiving a sham simulation.

As well as analyzing the subjects' gut microbiota through stool samples both before and after the trial, the team measured blood levels of insulin, pituitary gland hormones, glucose and a neurotransmitter called norepinephrine, which is known to affect microbiota composition.

The research team noted significant differences between the dTMS subjects and the control group after five weeks, with the dTMS subjects losing more than three percent of their total body weight and more than four percent of their fat.

Most interestingly, the stool samples showed that the dTMS subjects had greatly altered gut microbiota composition, including higher levels of several beneficial bacteria associated with anti-inflammatory properties and a general improvement in certain hormonal parameters. The control group receiving the sham stimulations were noted as having no clinically relevant changes in any of these areas.

"These changes suggest a beneficial effect of dTMS on both weight loss and change in microbiota composition," says Professor Livio Luzi, head of the research. "Our research shows the innovative ability of dTMS in exerting anti-obesity effects through alteration of the gut-brain axis."

The "gut-brain axis" is hot area of research at the moment, with scientists discovering the degree of interaction between brain function and gut bacteria to be significantly more complex and comprehensive than previously known. This is the first time researchers have shown that the gut microbiota can be altered through magnetic brain stimulation and it paves the way for fascinating new therapeutic interventions to battle obesity in the future.

The research will be presented on Sunday April 9th at ENDO 2017, the Endocrine Society's 99th annual meeting.