title: Probiotics improve outcomes after Roux-en-Y gastric bypass surgery: a prospective randomized trial.
abstract: BACKGROUND
  Roux-en-Y gastric bypass (RNYGB) surgery offers an effective and enduring treatment for morbid obesity. Gastric bypass may alter gastrointestinal (GI) flora possibly resulting in bacterial overgrowth and dysmotility. Our hypothesis was that daily use of probiotics would improve GI outcomes after RNYGB.
  
  
  METHODS
  Forty-four patients undergoing RNYGB were randomized to either a probiotic or control group; 2.4 billion colonies of Lactobacillus were administered daily postoperatively to the probiotic group. The outcomes of H(2) levels indicative of bacterial overgrowth, GI-related quality of life (GIQoL), serologies, and weight loss were measured preoperatively and at 3 and 6 months postoperatively. Categorical variables were analyzed by chi(2) test and continuous variables were analyzed by t test with a p < 0.05 for significance.
  
  
  RESULTS
  At 6 months, a statistically significant reduction in bacterial overgrowth was achieved in the probiotic group with a preoperative to postoperative change of sum H(2) part per million (probiotics = -32.13, controls = 0.80). Surprisingly, the probiotic group attained significantly greater percent excess weight loss than that of control group at 6 weeks (controls = 25.5%, probiotic = 29.9%) and 3 months (38.55%, 47.68%). This trend also continued but was not significant at 6 months (60.78%, 67.15%). The probiotic group had significantly higher postoperative vitamin B12 levels than the control group. Both probiotic and control groups significantly improved their GIQoL.
  
  
  CONCLUSIONS
  In this novel study, probiotic administration improves bacterial overgrowth, vitamin B12 availability, and weight loss after RNYGB. These data may provide further evidence that altering the GI microbiota can influence weight loss.
authors.affiliation: Department of Surgery, Surgery Center for Outcomes Research and Evaluation, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Gavitt A
authors.initials: GA
authors.lastname: Woodard
authors.forename: Betsy
authors.initials: B
authors.lastname: Encarnacion
authors.forename: John R
authors.initials: JR
authors.lastname: Downey
authors.forename: Joseph
authors.initials: J
authors.lastname: Peraza
authors.forename: Karen
authors.initials: K
authors.lastname: Chong
authors.forename: Tina
authors.initials: T
authors.lastname: Hernandez-Boussard
authors.forename: John M
authors.initials: JM
authors.lastname: Morton
mesh_terms: D000328:Adult; D015992:Body Mass Index; D016001:Confidence Intervals; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000175:diagnosis / Q000188:drug therapy* / Q000601:surgery*; D017060:Patient Satisfaction; D011182:Postoperative Care / Q000379:methods; D011183:Postoperative Complications / Q000517:prevention & control; D011336:Probability; D019936:Probiotics / Q000627:therapeutic use*; D011446:Prospective Studies; D012016:Reference Values; D018570:Risk Assessment; D016896:Treatment Outcome; D015431:Weight Loss