Cutting Back on Diabetes

It was discovered by accident more than a decade ago that weight-loss surgery often led to a dramatic improvement in the control of type 2 diabetes, often before patients left the hospital.

Today, evidence of the connection is so solid that some doctors say surgery should be considered as a treatment for diabetes, regardless of a person's weight.

"We thought diabetes was an incurable, progressive disease," says Dr. Walter J Pories, a professor of surgery at East Carolina University and a leading researcher on weight-loss surgery. "It . . . is a major cause of amputations, renal failure and blindness. This operation takes about an hour, and two days in hospital, and these people go off their diabetes medication. It's unbelievable."

As many as 86 percent of obese people with type 2 diabetes find their diabetes goes or is much easier to control within days of having weight-loss surgery, according to 19 studies discussed earlier this year in the American Journal of Medicine. But experts still aren't sure why obesity surgery helps to resolve type 2 diabetes or how long the effect might last. And they disagree on how big a role surgery should have.

"We are going from seeing the results to understanding why it happens," said Dr. Santiago Horgan, director of the Center for the Treatment of Obesity at the University of California, San Diego.

This much is clear: patients who have weight-loss surgery begin to lose weight rapidly, which by itself improves type 2 diabetes, allowing diabetics to more easily control their blood glucose levels. But something else seems to be occurring, too.

There is strong evidence that surgery -- especially gastric bypass surgery, which makes the stomach smaller and allows food to bypass part of the small intestine -- causes chemical changes in the intestine, says Dr. Jonathan Q Purnell, director of the Bionutrition Unit at Oregon Health Science University.

The small intestine has been thought of simply as the place where digestion occurs. But researchers now suspect it has other functions related to metabolism. Surgery somehow alters the secretion of hormones in the gut that play a role in appetite and help process sugar.