Roux-en-Y gastric bypass (RYGB) achieves type 2 diabetes remission beyond caloric restriction through which mechanism that distinguishes it from purely restrictive procedures?
- A Enhanced GLP-1 and PYY secretion from the Roux limb with accelerated nutrient delivery to the distal gut ✓
- B Decreased ghrelin secretion from the excluded fundus
- C Increased insulin sensitivity mediated by reduction in visceral fat alone
- D Delayed gastric emptying and prolonged satiety from the small gastric pouch
Explanation
The 'hindgut hypothesis' explains RYGB's superior anti-diabetic effect beyond weight loss: rapid delivery of nutrients to the distal small intestine (Roux limb bypasses stomach and proximal bowel) causes exaggerated secretion of incretin hormones GLP-1 (glucagon-like peptide-1) and PYY from L-cells in the distal ileum. GLP-1 stimulates insulin secretion, suppresses glucagon, and improves beta-cell function in a glucose-dependent manner. This explains why T2DM remission often occurs within days of RYGB, before significant weight loss, and is not seen with purely restrictive procedures like sleeve gastrectomy to the same degree.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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Written and medically reviewed by the StethoPrep medical team.