Increased glucagon-like peptide-1 (GLP-1) in type II diabetics: results of a high-fiber plant-based diet

Elizabeth Bailey Wakefield, The College of Wooster

Abstract

One highly effective and simple treatment for type II diabetes is dietary change; especially change to a high fiber, plant-based vegan diet. A recent observation regarding type II diabetics who have undergone a form of gastric bypass surgery, found that about four months post-surgery, 85% of the patients were no longer diabetic. Following surgery, glucagon-like peptide-1 (GLP-1), a hormone released by the latter third of the intestine, had been found to be markedly increased after a meal in gastric bypass patients. This significant increase in GLP-1 was due to the surgical rearrangement of the intestines, leading food to be emptied directly from the stomach into this latter part of the small intestine. It has been hypothesized that elevated levels of GLP-1 are responsible for the clinical resolution of diabetes in gastric bypass patients. The purpose of this study was to investigate whether a rise in GLP-1 could explain the marked improvement in glucose control seen in diabetic patients that switch to a high-fiber plant-based diet. This was investigated through the comparison of GLP-1 concentration in blood serum samples over a time course from two different meals in type II diabetic subjects. Four participants completed the study, and the results suggest that a high-fiber plant-based meal induces GLP-1 secretion faster (peaks at 1 hour) compared to the lesser amount of GLP-1 secreted after a calorie-matched low-fiber meal. With repetition of GLP-1 concentration measurements and an increase in sample size, GLP-1 could be a possible mechanistic explanation for increased glucose control in type II diabetics due to increased fiber intake from a plant-based diet.