Limiting weight regain with personalized fecal capsules

31 Aug 2020 --- Ingesting frozen microbiome capsules derived from consumers’ own feces may help sustain weight loss and glycemic control. A team of international researchers preserved the personal microbiome from fecal transplants after six months of weight loss and then transplanted the microbiome back via the fecal capsules. This process is called autologous fecal microbiota transplantation (aFMT) and resulted in test participants losing 8.3 kg on average after six months, comparable to the placebo group.

With consumer interest in the microbiome on the rise, this research provides a novel avenue of helping consumers on a diet prevent gaining back weight lost after four to six months of dieting, also known as the “regain phase,” as well as people who find their weight loss plateauing after a certain point.

“The ability to influence health through manipulation of our gut microbial communities is an area of intense research in recent years, with metabolism being a central field that is clearly influenced by the microbiome. The importance of the microbiome is becoming known to the general population and people are eager to improve their health through this novel approach,” lead author Dr. Iris Shai tells NutritionInsight.

“The concept of an ‘ideal gut microbial community’ is definitely an example of ‘personalized’ or ‘individualized’ medicine and each individual might need a slightly different composition to enjoy the maximal benefits. Thus, the concept of using the individuals’ own microbiome after optimization is potentially ideal. Furthermore, it is a lot safer to use participants’ own stool rather than transferring biological samples from person to person,” adds other lead author, Dr. Ilan Youngster.

In terms of this undertaking’s commercial viability, the researchers anticipate regulation of using a complex biological material as a therapeutic as challenging. Still, they are currently in the process of standardizing the optimization and delivery of the microbiome.

The green-Mediterranean diet was the only intervention to induce a significant change in microbiome composition during the weight loss phase.“The compliance with administration of repeated doses of fecal capsules was excellent with over 95 percent of patients completing the treatment protocol. The fact that people were offered their own fecal microbiome definitely made the process easier to accept,” Dr. Youngster adds. 

Eating fecal matter to lose weight?
In their 14-month study published in the journal Gastroenterology, the research team recruited 90 abdominally obese or dyslipidemic participants from Israel with an average age of 52. They were randomly assigned to one of three groups adhering to healthy dietary guidelines, the Mediterranean diet and a “green-Mediterranean diet.” 

The latter two groups consumed 28 g of walnuts daily. The green-Mediterranean dieters further drank three to four cups of green tea per day and a duckweed green shake made with 100 g of daily Mankai strain. All groups also received free gym memberships and instructions to engage in moderate-intensity physical activity.

After six months, the test subjects provided a fecal sample processed into aFMT through frozen, opaque and odorless capsules. The participants were then randomly assigned to the groups that either received 100 capsules containing their own fecal microbiota or a placebo, which they ingested for 14 months.

The primary outcome was regained lost weight over the expected regain phase. The green-Mediterranean diet was the only intervention to induce a significant change in microbiome composition during the weight loss phase. This prompted preservation of weight loss-associated specific bacteria and microbial metabolic pathways following the aFMT. 

Only 17 percent of green-Mediterranean diet group who had aFMT saw weight gain, compared to 50 percent of the green-Mediterranean diet group who had the placebo. This is the most drastic difference of the three diet groups. High-polyphenols, green plant-based or Mankai diet better optimizes the microbiome for an aFMT procedure, the study states.

“We are still looking into the mechanism of action. However, we believe that the direct influence of beneficial microbes as well as indirect influences through bacterial metabolites are potential reasons for the effect,” Dr. Shai indicates.

Potential benefits of aFMT
The next steps following these study results involve identifying the exact mechanisms by which beneficial bacteria can improve our metabolism, explain the authors. “Furthermore, we are working on identifying the ideal way to optimize the microbiome to be used as a substrate for future aFMT.”

“The transfer of fecal microbes from a healthy donor to a patient has been proven beneficial in several indications, the most successful being a disease called Clostridioides difficile infection. However, our group has been looking into other potential benefits of fecal microbiome transplantation, including the prospect of using your own fecal microbes to simplify the procedure,” Dr. Youngster concludes.

By Anni Schleicher