Twelve weeks of supplementation with the probiotic strain at a daily dose of 20 billion CFU led to significant reductions in body fat mass and percent body fat of 0.6 kg and 0.7%, respectively, reported the scientists in Bioscience of Microbiota, Food and Health.
“The composition of the gut microbiota differs between lean and obese subjects and is recognized as a therapeutic target of obesity,” the wrote. “These results suggest that B. breve B-3 is a promising probiotic strain for body fat reductions in healthy pre-obese individuals.
“To the best of our knowledge, B. breve B-3 is the only bifidobacterial strain to have induced significant reductions in body fat in a randomized controlled trial without lifestyle changes, such as calorie restrictions, or any combination with other pre/probiotics.”
Gut microbiota and obesity
The link between the gut microbiota and obesity was first reported in 2006 by Jeffrey Gordon and his group at Washington University in St. Louis, who found that microbial populations in the gut are different between obese and lean people, and that when the obese people lost weight their microflora reverted back to that observed in a lean person. This suggested that obesity has a microbial component (Nature, Vol. 444, pp. 1022-1023, 1027-1031).
A 2013 paper in Science (Vol. 341, Issue 6150), also led by Prof Gordon, found that transplanting gut bacteria from obese humans into germ-free mice leads to greater weight gain and fat accumulation than mice that were given bacteria from the guts of lean humans.
The findings showed that weight and fat gain is influenced by communities of microbes in the gut and their effect on the physical and metabolic traits of the host, leading to metabolic changes in the rodents that are associated with obesity in humans.
For the new study, scientists from Morinaga and the National Hospital Organization Kyoto Medical Center recruited 80 pre-obese but otherwise healthy Japanese adults to participate in their randomized, double-blind, placebo-controlled trial. Half of the participants were randomly assigned to receive B. breve B-3 capsules and the other half to placebo for 12 weeks.
Results showed that visceral fat area significantly increased after both four and eight weeks in the placebo group, but no significant changes were observed in the probiotic group. In addition, percent body fat and body fat mass significantly decreased in the B-3 group at eight and 12 weeks, compared to placebo.
The decreases in both percent body fat and body fat mass were similar to those reported by a meta-analysis of 15 randomized controlled trials published in Obesity Reviews (2018, Vol. 19, No. 2, pp. 219-232). The meta-analysis, which included studies using a range of different probiotic strains, found average reductions in body weight and fat percentage of 0.6 kg and 0.6%, respectively.
In addition, the Morinaga scientists reported no differences between the groups for blood markers. However, slight decreases in triglyceride levels and increases in HDL cholesterol levels were observed for the probiotic group, compared to baseline.
Importantly, no adverse effects were recorded for participants in the B. breve B-3 group.
Commenting on the potential mechanism(s) of action, the researchers note that B. breve B-3 may induce fatty acid oxidation, boost energy expenditure, and increase bile acid synthesis.
“Therefore, a strain of B. breve B-3 is safe for a healthy population and may be useful for preventing body fat accumulation and related metabolic disorders in pre-obese individuals,” they concluded.
Source: Bioscience of Microbiota, Food and Health
2018, Volume 37, Number 3, Pages 67-75. doi: 10.12938/bmfh.18-001
“Effects of Bifidobacterium breve B-3 on body fat reductions in pre-obese adults: a randomized, double-blind, placebo-controlled trial”
Authors: J. Minami et al.