Related Experiment Video
Updated: Jan 22, 2026

A Gut-on-a-Chip Model to Study the Gut Microbiome-Nervous System Axis
Published on: July 28, 2023
Changes in Gut Microbiome after Bariatric Surgery Versus Medical Weight Loss in a Pilot Randomized Trial
Clare J Lee1, Liliana Florea2,3, Cynthia L Sears4,5
1Divisions of Endocrinology, Diabetes & Metabolism, The Johns Hopkins University, 1830 E. Monument St, Baltimore, MD, 21287, USA. clee158@jhmi.edu.
Background:
Gut microbiota likely impact obesity and metabolic diseases. We evaluated the changes in gut microbiota after surgical versus medical weight loss in adults with diabetes and obesity.
Methods:
We performed 16S rRNA amplicon sequencing to identify the gut microbial composition at baseline and at 10% weight loss in adults with diabetes who were randomized to medical weight loss (MWL, n = 4), adjustable gastric banding (AGB, n = 4), or Roux-en-Y gastric bypass (RYGB, n = 4).
Results:
All participants were female, 75% reported black race with mean age of 51 years. At similar weight loss amount and glycemic improvement, the RYGB group had the most number of bacterial species (10 increased, 1 decreased) that significantly changed (p < 0.05) in relative abundance. Alpha-diversity at follow-up was significantly lower in AGB group compared to MWL and RYGB (observed species for AGB vs. MWL, p = 0.0093; AGB vs. RYGB, p = 0.0093). The relative abundance of Faecalibacterium prausnitzii increased in 3 participants after RYGB, 1 after AGB, and 1 after MWL.
Conclusions:
At similar weight loss and glycemic improvement, the greatest alteration in gut microbiota occurred after RYGB with an increase in the potentially beneficial bacterium, F. prausnitzii. Gut microbial diversity tended to decrease after AGB and increase after RYGB and MWL. Future studies are needed to determine the impact and durability of gut microbial changes over time and their role in long-term metabolic improvement after bariatric surgery in adults with type 2 diabetes.
Clinical Trial Registration:
NCTDK089557- ClinicalTrials.gov.
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