Metabolic & Cardiometabolic
ileal nutrient delivery increases GLP-1 secretion
📅 Last reviewed: 2026-08-11 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Human trials (RCT / n-of-1)
How the studies fall
What the evidence shows
The 'ileal brake'. Directly tested in humans by infusing nutrient into the terminal ileum through a catheter or ileostomy, which is about as clean a test of the mechanism as is ethically available. Consistent and sizeable: even 30 cm of ileum exposed to glucose produces substantial GLP-1 release, and the response tracks active glucose absorption.
The evidence (4)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Wen J, et al. 1995 · The American journal of physiology | animal | supports | moderate | Canine ileal/colonic perfusion with nutrient raised plasma PYY and GLP-1 and delayed duodenal migrating motor complexes, establishing the peptide basis of the ileal brake. Dog. |
| van Avesaat M, et al. 2015 · International journal of obesity (2005) | RCT | supports | moderate | Randomized single-blind crossover, n=13, naso-ileal catheter. Ileal infusion of lipid, casein and sucrose activated the ileal brake with macronutrient-specific effects on GI peptide release and food intake. |
| van Avesaat M, et al. 2017 · International journal of obesity (2005) | RCT | supports | moderate | Double-blind randomized placebo-controlled crossover, n=14, naso-ileal catheter. Protein infused into duodenum vs jejunum vs ileum showed a location-specific gradient in GLP-1/PYY/CCK release and food-intake feedback, with the distal site most active. |
| Zhang X, et al. 2022 · Metabolism: clinical and experimental | RCT | supports | high | Double-blind randomized crossover, n=10 with loop ileostomy. 30 g glucose infused into 30 cm of terminal ileum produced substantial increases in plasma GLP-1 vs saline, with only minimal changes in glucose/insulin/C-peptide and no change in ghrelin, GIP or glucagon. GLP-1 response strongly related to active glucose absorption (serum 3-OMG). NCT05030376. |
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