Probiotics backed for weight loss benefits: Meta-analysis

Weighted mean difference calculations in a meta-analysis of 15 studies of probiotic supplementation showed larger reductions in body weight, body mass index (BMI) and fat percentage in the intervention group compared with placebo, found the researchers writing in Obesity Reviews.

“Our meta-analysis showed that short-term (≤12 weeks) probiotic supplementation reduced body weight, BMI and fat percentage, but the effect sizes were small​,” wrote first author Dr. Heidi Borgeraas from the Morbid Obesity Centre, Vestfold Hospital Trust, Tønsberg, Norway.

Additionally, there was no significant effect of probiotic supplementation on fat mass.  

Two previous reviews had drawn similar conclusions on body weight and BMI. However, in one of these, intervention groups in many of the included studies received prebiotics as well as probiotics.  Additionally, neither review considered the effect in overweight or obese subjects, population types which might benefit the most from weight loss.

Probiotic genera/ species​

The trials included in the review all had interventions of between 3-12 weeks. All except three studies used Lactobacillus. ​Subgroup analysis did not show differing effect sizes between these three and those using Lactobacillus. ​ No further subgroup analysis of dosage effect was performed, as the daily supplemented dose did not show large variations between studies.

A large number of the studies included multiple genera and species of probiotic. The researchers thus noted a lack of specificity of the effects of individual genera and species on the endpoints. 

The researchers suggested that “the risk of bias within included studies was low, but, importantly, a number of trials were not registered and/or lacked a priori sample size calculation and were thus regarded as having unclear or high risk of reporting and other biases.”​

For this reason, they recommended that “further long-term studies are required to examine the effects of probiotic supplementation on various measures on body weight.”​

Source: Obesity Reviews​
Published online, doi: 10.1111/obr.12626​​
“Effects of probiotics on body weight, body mass index, fat mass and fat percentage in subjects with overweight or obesity: a systematic review and meta-analysis of randomized controlled trials”​
 Authors: H. Borgeraas, L. K. Johnson, J. Skattebu, J. K. Hertel, J. Hjelmesæth