A clinical trial testing fecal transplants in severely obese subjects with metabolic syndrome has found the treatment to be only beneficial when accompanied by non-fermentable fiber supplements. The phase 2 trial saw improvements in insulin sensitivity six weeks after a single fecal transplant.
We know our gut bacteria influence our general health but the big challenge researchers are currently facing is finding a way to turn that knowledge into therapeutic treatments for disease. Perhaps the most straightforward method is simply taking fecal samples from a healthy person and administering them to an unhealthy person.
Known as fecal microbial transplantation (FMT), this method is pretty much what you would imagine. Stool from a donor is screened for dangerous bacterial organisms and then prepared into capsules that are taken orally (or sometimes mixed with saline and administered through the other end). The goal is to repopulate an unhealthy subject’s microbiome with good bacteria from a healthy subject.
“We know that the gut microbiome affects all of these processes – inflammation, metabolism, immune function,” explains Karen Madsen, from the University of Alberta and principal investigator on the new research. “The potential for improving human health through the microbiome is immense. We are only scratching the surface at the moment.”
Unfortunately, clinical trials testing FMT have so far deliver mixed results. Obesity, inflammatory bowel disease, alcoholism and even autism have all been targeted with FMT. And while there are promising indications of efficacy, nothing has really proven consistent enough to get over the line.
This new study looked at whether administering specific fiber supplements alongside the FMT could enhance therapeutic outcomes. Madsen hypothesized these supplements could be key to the success or failure of FMT.
“When you transplant beneficial microbes, you need to feed them to keep them around,” she notes. “If you give a new microbe and you don’t feed it, if you continue to eat a diet of processed foods and no fiber, then that microbe will likely die.”
Seventy participants were recruited for the trial, all with severe obesity and metabolic syndrome. The cohort was blindly and randomly split into four groups: FMT + high-fermentable fiber supplements, FMT + non-fermentable fiber supplements, and a placebo group for each of the fiber supplements. A single dose of FMT, comprising 20 capsules, was administered at the beginning of the trial and then fiber supplements were taken daily for the next six-weeks.
At the end of the trial only the FMT group taking the non-fermentable fiber supplements showed improvements in insulin sensitivity, the primary outcome being assessed. All other groups showed no change.
“Non-fermentable fiber can change gut motility – how fast things move through – as well as acting as a bulking and binding agent that can change levels of bile acids, which could help explain our results,” says Madsen.
Madsen optimistically speculates this FMT/fiber therapy could be clinically available in five years if further trials are successful. But perhaps the most immediate takeaway is the suggestion some kind of prebiotic supplementation could be a vital accompaniment to any treatment trying to alter one’s gut microbiome.
The new study was published in the journal Nature Medicine.
Source: University of Alberta