Impact of Lactobacillus GG on weight loss in post-bariatric surgery patients: a randomized, double-blind clinical trial

Introduction and Objectives: There is increasing evidence suggesting the impact of human gut microbiota on digestion and metabolism. It is hypothesized that the microbiome in obese subjects is more efficient than that in lean subjects in absorbing energy from food, thus predisposing to weight gain. A transformation in gut microbiota has been demonstrated in patients who have undergone bariatric surgery which has been positively associated with post-surgical weight loss. However, there is lack of studies investigating the impact of probiotics on weight loss in post-bariatric surgery patients. The objectives of our study were to investigate the impact of a probiotic, Lactobacillus GG (LGG), on weight loss and quality of life in patients who have undergone bariatric surgery. Methods: The study was registered with ClinicalTrials.gov NCT01870544. Subjects were randomized to receive either LGG or placebo capsules. Percent total weight loss at their post-operative visits was calculated and differences between the two groups were tested using a t-test with unequal variances. The effect of LGG on Gastrointestinal Quality of Life Index (GIQLI) scores was estimated using a mixed model repeated measures model. Results: The mean rate of change in percent total weight loss at the ‘30-day’ post-operative visit for the placebo and treatment groups was 0.098 and 0.079 (p = 0.41), respectively, whereas that at the ‘90-day’ post-operative visit was 0.148 and 0.126 (p = 0.18), respectively. The difference in GIQLI scores on ’30-day’ and ’90-day’ visits were 0.5 (-7.1, 8.0), p=0.91 and 3.7 (-4.9, 12.3), p=0.42, respectively. LGG was recovered from the stools of 3 out of 5 subjects in the treatment group.. Conclusion: We did not appreciate a significant difference in the mean rate of weight loss or GIQLI scores between the groups who received LGG versus placebo. This study demonstrated survival of lactobacillus during transit through the gastrointestinal tract.