Bariatric surgery may be about metabolic health rather than limiting consumption
The Los Angeles Times reports on the results of a new study of the benefits of bariatric surgery”
The study randomly assigned 150 overweight and obese people with Type 2 diabetes to one of three groups. Those in the control group had their diabetes managed with medications and daily blood-glucose monitoring. They also received intensive counseling about diet and exercise, including regular weigh-ins to monitor their progress. After three years, they had lost an average of 9.5 pounds.
The second group in the trial got Roux-en-Y gastric bypasses, in which the stomach is reshaped and relocated to divert most food past much of the lower intestine, where nutrients and calories are largely absorbed. The third group got a procedure called sleeve gastrectomy, which staples some 80% of the stomach closed, creating a banana-shaped tube where once a large pouch existed. Patients who had surgery received intensive medical management and lifestyle counseling as well.
Three years later, those who had the Roux-en-Y bypass had lost an average of nearly 58 pounds, and those who had sleeve gastrectomy lost an average of 47 pounds.
More importantly, Schauer said, the patients in the surgery groups were much more likely to have their diabetes under control — 58% of those who had Roux-en-Y and 33% of those who had sleeve gastrectomy were able to stop taking diabetes medications. Only 5% of patients in the control group achieved the same endpoint after three years, and none were able to discontinue medications completely.
In addition, study volunteers who had gastric bypass whittled their daily number of blood pressure and cholesterol-lowering medications from 2.73 to 0.96, on average. And subjects who had sleeve gastrectomy reduced their average number of cardiovascular medications from 2.18 to 1.35 three years later.
The medication tally for the control group didn’t budge.
Sadly, the report does not discuss the possible mechanism(s) responsible for this result. The theory behind bariatric surgery was that it would work simply by restricting the volume of food that the patient could consume. It turns out that it seems to be driven more by the way it resets metabolic health in general and insulin sensitivity in particular.
Once he was awarded funding, Brady began collecting fat samples from bariatric surgery patients with the help of a research assistant. The samples were collected two weeks before the surgery, and then again two weeks after the surgery.
“We added varying dosages of insulin to the samples to test the sensitivity, to create a dose-response curve,” Brady said. “And what we found that there was a huge increase in both insulin sensitivity and responsiveness just two weeks after the procedure.”
Brady found that these results could be reproduced in each patient undergoing a Roux-en-Y or duodenial switch.
“Bariatric surgery seems to ‘reboot’ fat cells so that they do their job properly, absorbing and retaining the lipids,” Brady said. “However, there are likely to be more subtle molecular and metabolic differences between the two procedures. This is something we’re hoping to examine in a larger study.”
It would be great to see the conversation about type 2 diabetes and obesity shift further away from the overeating paradigm to a metabolic health paradigm.