Fecal microbial transplantation (FMT) is the process of transferring the microbial populations from the intestine of a healthy individual into that of a patient with the aim to treat a medical condition. World-leading scientist Professor Jens Walter was among an international team of researchers that discovered that the beneficial effects of  FMT in patients with obesity and metabolic syndrome can be improved by the supplementation of dietary fiber. The results from this work, published in the prestigious journal Nature Medicine, serve as a basis for the development of novel microbial therapeutic strategies aimed at combatting the growing worldwide epidemic of obesity. Prof Walter is based in University College Cork where he is a Principal Investigator at APC Microbiome Ireland SFI Research Centre and Professor at the School of Microbiology, Department of Medicine. The work was carried out in collaboration with the University of Alberta in Canada under the leadership of Prof Karen L Madsen.

Prof Paul Ross, Director of APC Microbiome Ireland SFI Centre says “APC Microbiome Ireland carries out ground breaking research in the area of the gut microbiome to help create solution to improve human health and quality of life. FMT is proving to be a highly effective therapy and Prof Walter’s work in this area is of great significance. This work will benefit researchers and clinicians all over the world find more successful ways to treat patients with obesity, metabolic syndrome and other conditions.”

Positive outcomes:

• From baseline to six weeks, participants receiving FMT and low-fermentable fiber demonstrated significant improvements in insulin sensitivity.
• Observed significant reductions in blood pressure for all patients receiving either FMT or low-fermentable fiber interventions.
• The paper is published in the high impact journal Nature Medicine.

“This study proves that a single-dose oral FMT combined with daily low-fermentable fiber supplementation can alleviate insulin sensitivity in patients with severe obesity and metabolic syndrome,” said Professor Walter, who was listed as one of the world’s most influential scientists in the global 2020 Highly Cited Researchers List. “This is the first human study to combine FMT with dietary fiber supplementation to improve human metabolic health. FMTs are not explored for a large variety of medical conditions. Our study provides a proof-of-concept that the effects of this promising therapeutic approach can be enhanced with dietary modulations, something that has not explored before.”

Obesity and metabolic syndrome are two of the greatest health epidemics of the twenty-first century. Current medical strategies are regarded to have limited efficacy, poor tolerance, and high cost. Continued lack of progress in curbing this epidemic has drawn growing interest into new approaches such as FMT which target the gut microbiome.

The gut microbiome is the community of microbes, bacteria, fungi and viruses, which colonise our digestive tracts. It is central to human health and the prevention of chronic diseases. Understanding the role of the gut microbiome in chronic diseases is of profound scientific interest and clinical significance. FMT from lean donors to patients with obesity has been associated with metabolic benefits but results from previous studies have been inconsistent. In this study the outcomes included an improvement in insulin sensitivity, blood pressure and heart rate. A reduction in BMI, hip and waist circumference were also observed and the participants reported better quality of life.

It is important to note the clinical use of FMT in conditions other than Clostridioides difficile infection is currently explorative and not yet an established and approved medical practice. The benefit-to risk ratio is not yet clear. Earlier this year, the journal Allergy published a review by Prof Walter and Dr Tom Marrs from King’s College (London, UK) that presented the arguments for and against the use of FMT. They also identified research gaps and recommended how these may be addressed in future studies. Clearly, FMT therapy should only be taken under appropriate medical direction and supervision.