Effects of Probiotics Supplementation on Gastrointestinal Symptoms and SIBO after Roux-en-Y Gastric Bypass: a Prospective, Randomized, Double-Blind, Placebo-Controlled Trial

Obes Surg. 2021 Jan;31(1):143-150. doi: 10.1007/s11695-020-04900-x. Epub 2020 Aug 11.


Bariatric surgery may cause undesirable gastrointestinal symptoms due to anatomical, functional and intestinal microbiota changes.

Purpose: The aim of this study was to evaluate the effect of probiotic supplementation on gastrointestinal symptoms and small intestine bacterial overgrowth (SIBO) in patients after Roux-en-Y gastric bypass (RYGB).

Materials and methods: This is a prospective, randomized, double-blind, placebo-controlled trial. The patients were randomized into Control Group (CG) (n = 39) and Probiotic Group (PG) (n = 34). The PG received tablets containing Lactobacillus acidophilus and Bifidobaterium lactis (5 billion CFU/strain) for 90 days, and the CG received tablets with starch. Both the Gastric Symptom Rating Scale (GSRS) questionnaire and 3-day food record were answered before surgery (T0) and after 45 days (T1) and 90 days of surgery (T2). At T0 and T2, hydrogen breath test was used to verify the presence of SIBO.

Results: The prevalence of SIBO was similar among times, and the mean score of GSRS responses did not differ between groups at any time. However, PG patients reported less bloating compared to CG, more abdominal pain at T1 (which reduced at T2), more episodes of soft stools and nausea and less hunger pain after surgery, with no reports of urgent episodes to evacuate, even though they consumed more fat than the CG.

Conclusions: The supplementation of L. acidophilus and B. lactis is effective in reducing bloating, but without influencing the development of SIBO in the early postoperative period.

Keywords: Bariatric surgery; Gastrointestinal symptoms; Probiotics.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Double-Blind Method
  • Gastric Bypass* / adverse effects
  • Gastrointestinal Microbiome*
  • Humans
  • Obesity, Morbid* / surgery
  • Probiotics* / therapeutic use
  • Prospective Studies