The obesity epidemic continues unabated in spite of many decades of treatment efforts.
Attention is turning to the microbiome whose composition may contribute to obesity. Earlier research showed that certain microbes control fat storage. In a groundbreaking experiment by Peter Turnbaugh and colleagues at Washington University in Missouri, obesogenic microbes transferred into germ-free mice found those animals went on to be fatter than those with the lean microbes. The researchers stated that the obese microbiome has an increased capacity to harvest energy from the diet.
In addition, studies in mice have shown that the intestinal microbiota can contribute to obesity via the anorexigenic gut hormone glucagon-like peptide 1 (GLP1) and bile acids which affect lipid metabolism.
Could this work in humans?
Let’s take a look at one recent study. Jessica R. Allegretti of Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts and colleagues performed a randomized, placebo-controlled, pilot study of the effects of fecal microbiota transplantation (FMT) in obese, metabolically uncompromised patients.
Effects of Fecal Microbiota Transplantation With Oral Capsules in Obese Patients appeared in Clinical Gastroenterology and Hepatology in July of 2019.
The double-blind study
22 obese patients without a diagnosis of diabetes, nonalcoholic fatty liver or metabolic syndrome were assigned randomly to one of two groups. One group received fecal microbiota transplantation (FMT) by capsules taken from a single lean donor. The second group received placebo capsules.
Stool and serum samples were collected from patients at baseline and at numerous later weeks and analyzed.
- Safety: no differences in adverse events between patients who received FMT vs placebo
- No increase in the area under the curve of glucagon-like peptide 1(GLP1) in either group.
- FMT group had sustained shifts in microbiomes associated with obesity toward those of the donor.
- No changes in mean BMI at week 12 in either group
In a placebo-controlled pilot study, we found that FMT capsules (derived from a lean donor) were safe but did not reduce BMI in obese metabolically uncompromised patients. The FMT capsules were well tolerated and led to sustained changes in the intestinal microbiome and bile acid profiles that were similar to those of the lean donor.Jessica R. Allegretti, Zain Kassam, Benjamin H. Mullish, Austin Chiang, Madeline Carrellas, Jonathan Hurtado, Julian R. Marchesi, Julie A.K. McDonald, Alexandros Pechlivanis, Grace F. Barker, Jesus Miguens Blanco, Isabel Garcia-Perez, Wing Fei Wong, Ylaine Gerardin, Michael Silverstein, Kevin Kennedy, Christopher Thompson,
Effects of Fecal Microbiota Transplantation With Oral Capsules in Obese Patients,
Clinical Gastroenterology and Hepatology,
This study established safety and FMT as a biomarker change agent. Whether this translates into meaningful weight loss has yet to be determined.