You may have heard that bariatric (weight loss) surgery “cures diabetes.” As a result, bariatric surgeries are being done on people at ever-lower weights. But do these surgeries really work, and if so, how? And are they safe?
In December, I attended a program at University of California, San Francisco, about bariatric surgery for diabetes. The speaker explained that these surgeries should properly be called “metabolic surgery,” because they do NOT work primarily by restricting intake or blocking absorption. They work by changing the way our intestines respond to food.
It turns out that the intestines are filled with glands that secrete all kinds of hormones and neurotransmitters. The intestinal glands are responsible for signaling insulin production, promoting storage of starch and fat, appetite control, and a whole lot of other things. The gut does a lot more than just absorb food into the blood. It orchestrates how our bodies use food.
Different parts of the intestine have different glands. So if you rearrange the intestines so that food is kept away from certain glands, and shunted toward other glands, it can change the way we handle carbs, proteins, and fats. One new “metabolic surgery” is called an “ileal transposition.” The surgeon takes a piece from the end of the small intestine (a part of the hindgut called the ileum), and sews it back in at the top of the intestine, right where food comes out of the stomach. Nothing is permanently removed or bypassed, but just moving the glands around causes big weight loss and better glucose control.
How does this work? Even the surgeons who are doing it don’t really understand. It may be that the hindgut produces more of an insulin-promoting hormone called GLP-1, the same one that is promoted by drugs like Byetta (exenatide).
Apparently moving glands that used to be at the end of the intestine, where all the food was already mixed and partially digested, up to the top, where they deal with all the refined foods right off the plate, leads to very different production of insulin and other vital hormones, like being on constant natural Byetta or Januvia. But there are undoubtedly other factors involved.
Note that these positive results were completely unexpected. Doctors thought they were just shortening the intestine or shrinking the stomach so people would eat less or absorb less. They didn’t realize they were screwing around with people’s hormones and body chemicals, but it turns out that may be a good thing. Or it may not.
Some critics argue that our intestines evolved over millions of years, and we have no idea why they are the way they are. If we just start chopping them up and moving them around, there are bound to be nasty long-term effects. But the surgeons would reply that the environment our intestines evolved for is very different from the environment we’re living in now. It may be that our evolved intestines are no longer well equipped for the changed food world, with all its sugars and refined foods.
Is It Good For You?
Many studies show that different kinds of metabolic surgery help control blood glucose. But that doesn’t necessarily make them a good idea. The side effects can be debilitating. They can make your life miserable. I spoke with one woman who had lost 130 pounds and developed near-normal blood glucose after a Roux-en-Y gastric bypass. Her husband, who had left her because she was “too fat”, came back to her.
Success story, right? Maybe (although I don’t know about taking the husband back)… but physically she’s miserable. She can eat only very small amounts, and most foods she can’t eat at all without getting sick. She has constant nausea and frequent abdominal pains. Is this worth it for her? She’s not sure.
We also don’t know yet how long the metabolic “benefits” will last. We do know that weight is often regainedin 2–5 years after surgery. A recent study shows that postprandial (after-meal) glucose levels can remain high in people who have had metabolic surgery, even if their A1Cs indicate that their diabetes is “cured.”
If you’re considering “bariatric” or “metabolic” surgery, I would encourage you to check it out in detail. What are you getting yourself into? If you do go ahead, choose a surgery with the fewest side effects. (Although they all have pretty many, some have fewer than others.) Consult with other people who have had the surgery, including some that are at least two years past their operation. See if it’s still worth it for them.
And consult with our Diabetes Self-Management community. How many of our readers have had, or thought about, bypasses, bandings, transpositions, and other surgeries for diabetes and/or weight? How has it gone for you?