Probiotics and synbiotics have antiobesity effects Original paper

In this meta-analysis of randomized controlled trials, supplementation with probiotics or synbiotics reduced body weight and improved body composition in adults.

The effect of supplementation with probiotics or synbiotics on body weight, BMI, body fat percentage, fat mass, fat-free mass, lean body mass, waist circumference, and waist-hip ratio.

12,603 men and women (ages 18–82; average BMI of 19.1–38.8), including participants with overweight/obesity, cognitive disorders, metabolic disorders, or neurological disorders, as well as participants with no known health conditions.

A meta-analysis of 200 randomized controlled trials was performed. Most of the trials were conducted in Asia, followed by Europe, the United States, and Oceania. Of the 200 trials, 150 gave the participants probiotics and 50 gave synbiotics. The probiotics/synbiotics were administered as food (e.g., yogurt) or as a supplement. The intervention duration ranged from 2 to 56 weeks.

Supplementation with probiotics/synbiotics reduced body weight by 0.91 kg (2 lb; moderate certainty), BMI by 0.28 (low certainty), waist circumference by 1.1 cm (moderate certainty), fat mass by 0.92 kg (2 lb; high certainty), body fat percentage by 0.68% (moderate certainty), and waist-hip ratio by 0.01 (low certainty).

There was a negative linear relationship between trial duration and body weight, BMI, and fat mass, meaning that weight loss and fat loss seemed to increase the longer people were taking probiotics/synbiotics.