How does bypass surgery cure diabetes?

October 20, 2013

John DiTraglia MD

Contributing Columnist

Weight loss can improve Type 2 diabetes. Bypass surgery for weight loss can also cure diabetes but the diabetes is cured before you lose weight. So how does that work?

Part of the answer to this is revealed in a report by investigators from Boston Children’s Hospital. (1) - in rats anyway.

They found that glucose was taken up by the intestines as they began expressing a glucose transporter protein after gastric bypass in these rats. This is apparently part of a process of intestinal expansion that happens after this surgery. This increased glucose uptake by the intestines in turn leads to more normal blood glucose.

Surgery has been found to improve Type 2 diabetes even more than an equivalent weight loss by dieting. Furthermore can weight loss by dieting cause intestinal hypertrophy, that is increased size and weight? It might make sense that that would happen in reaction to weight loss, as your body tries fight back. Or are there two entirely different mechanisms. Answering that question sounds like a good job for one of my students.

Maybe someday we can find a way to cause this intestinal metabolic change without such drastic surgery.

1. Saeidi N et al. Reprogramming of intestinal glucose metabolism and glycemic control in rats after gastric bypass. Science 3013;341:406-10.