Weight-loss surgery can help diabetes disappear; new study suggests why


Weight-loss surgery could be a quick diabetes fix for some people, some studies have suggested, and now researchers are getting closer to an explanation as to why that might be the case. And it’s about much more than weight loss.

Researchers from Columbia University and Duke University studied two groups of obese diabetic patients at a hospital in New York. Ten people had a type of gastric bypass surgery that essentially reduces the size of the stomach, and 11 people were put on a strict diet. People in both groups lost from 22 to 26 pounds on average.

Scientists measured and assessed the circulating amino acids and acylcarnitines in the blood of subjects -- animal studies have suggested they might be related to insulin resistance. (Amino acids are the building blocks of proteins; acylcarnitines are fatty acids that have bound to carnitine). And indeed they found a significant decrease in “branched chain” amino acids within one month among the patients who had weight-loss surgery. But even after two months, the patients on dietary intervention had very little or no change in branched-chain amino acids. This WebMD story offers a fuller portrait of the research.

Essentially, the lower the concentration of branched-chain amino acids, the less insulin resistant the patients were, the researchers reported online Wednesday in Science Translational Medicine. They replicated their findings in a smaller group of obese patients at Duke and found the branched-chain amino-acid levels were still lower after six months among those who had gastric bypass surgery.

In short, something about the surgery, not the weight loss itself, seems to be improving glycemic control -- and amino-acid levels appear to have a role. But it’s unclear if the amino acids cause lower resistance to insulin. Two cardiologists from Massachusetts General Hospital write in a related Perspective:

“Further work is needed to establish whether the reduction in concentrations of circulating amino acids after weight loss is the cause or consequence of improvements in insulin sensitivity.”

But, safe to say, the research adds to a growing consensus that the benefits of gastric bypass surgery need to be further explored.

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