It is a well known fact that diabetes essentially disappears after having the Roux-en-Y gastric bypass surgery (RNY). Very often, within a matter of days after having surgery, blood sugars are normalized in the average bariatric patient. Since the patient has only lost several pounds, weight loss cannot explain the normalization of the blood sugars. So what is? The fact is, nobody knows for certain but there are theories about this as well as clinical research.

One theory is that by changing the anatomy of the intestinal tract, certain hormone secreting cells in the gut are brought in closer proximity to the pancreas which amplifies their effect on the pancreas. Two hormones in particular, glucacon-like peptide (GLP1) and gastric inhibitory peptide (GIP), are hormones that are manufactured from special cells in the distal intestine, the ileum. GLP1 in particular stimulates the pancreatic beta cells to secrete insulin. As mentioned above, the RNY brings the GLP1 secreting cells much closer to the pancreas and these cells are stimulated to secrete the GLP1 hormone every time a meal is eaten. Therefore, after a RNY is performed, the pancreas receives much more stimulation from GLP1 with every meal so, if the patient still has some degree of pancreatic function left, it responds more vigorously to each meal.

The above explanation makes perfect sense, but things are never as simple as they seem. Based on a number of studies performed on rats, it appears another mechanism is more likely. Although it has not yet been identified, some studies suggest that there may another hormone which acts as an antagonist to GLP1. It is thought that this hormone is secreted by the proximal intestine, or duodenum. This is the part of the intestine that is actually bypassed in the RNY procedure. It is thought that if this hormone exists, its levels go down after a RNY is performed. Therefore the GLP1 hormone is allowed to exert its effect on the pancreas without any interference from this hormone, labeled an anti-incretin. Therefore, based on rat studies where various surgeries were performed on the gut, this theory appears to be more plausible.

It is obvious that much more research is needed in this area before we get a clear answer to this question. I find it exciting though, that we are making definite progress in our understanding of diabetes which will lead to more effective treatments in the future. Stay tuned!