Probiotics May Improve Weight Loss After Gastric Bypass Surgery

Laurie Barclay, MD

July 16, 2009

July 16, 2009 — Probiotics may improve weight loss and other outcomes after Roux-en-Y gastric bypass (RNYGB) surgery, according to the results of a prospective, randomized trial reported in the July issue of the Journal of Gastrointestinal Surgery.

"Surprisingly, the probiotic group attained a significantly greater percent of excess weight loss than that of [the] control group," senior author John M. Morton, MD, from the Surgery Center for Outcomes Research and Evaluation at Stanford University School of Medicine in California, said in a news release.

"Part of the obesity puzzle may be due to the kind of bacteria you have in your intestine," Dr. Morton said. "Bacterial overgrowth can be bad in that it changes your motility, how you empty.... I thought, 'Well, if we give these patients probiotics, then maybe we can improve these symptoms.' "

In this study, 44 patients undergoing RNYGB in 2006 or 2007 were assigned to either the control group or the probiotic group, in which postoperative patients were given 2.4 billion colonies of Lactobacillus daily. Both groups received standard bariatric care, nutritional counseling, and weight-loss study support groups and were permitted to consume yogurt.

Before surgery and at 3 and 6 months postoperatively, the investigators measured H2 levels indicative of bacterial overgrowth, gastrointestinal-related quality of life, serologies, and weight loss. Analysis was by chi-square test for categorical variables and by t-test for continuous variables, with P < .05 for significance.

In the probiotic group, bacterial overgrowth at 6 months was statistically significantly reduced (preoperative to postoperative change of sum H2 parts per million: probiotic group, −32.13; control group, 0.80). Compared with the control group, the probiotic group had significantly greater percent excess weight loss at 6 weeks (control group, 25.5%; probiotic group, 29.9%) and 3 months (38.55% vs 47.68%). At 6 months, the difference between groups still favored the probiotic group but was no longer statistically significant (60.78% vs 67.15%).

Postoperative vitamin B12 levels were significantly higher in the probiotic group than in the control group (1214 pg/mL vs 811 pg/mL at 3 months), and gastrointestinal-related quality of life significantly improved in both groups.

Limitations of this study include lack of placebo control, older age and more diabetes in the probiotic group, and insufficient power to detect a statistically significant difference in weight loss (which was seen nevertheless at 6 weeks and at 3 months).

"In this novel study, probiotic administration improves bacterial overgrowth, vitamin B12 availability, and weight loss after RNYGB," the study authors write. "These data may provide further evidence that altering the [gastrointestinal] microbiota can influence weight loss."

This study received no external support. The authors have disclosed no relevant financial relationships.

J Gastrointest Surg. 2009;13:1198–1204.


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