It's a phenomenon seen in recent years by doctors who increasingly are using the operation not only to help patients lose weight and improve their health generally but specifically to address the national epidemic of Type 2 diabetes.
The researchers plan to begin studies with humans this fall, though a pill to cure diabetes may be a long way off, said Steven D. Munger, a professor of anatomy and neurobiology in Maryland School of Medicine who has been working with other researchers on animals models for more than two years.
"If we could find a way of mimicking the anti-diabetes surgery without surgery, it might be a nice alternative and whole new way of therapeutically addressing diabetes," said Munger, whose research recently was published in the American Journal of Physiology – Endocrinology and Metabolism.
"Everyone might not be a candidate or want surgery," he said.
Almost 26 million Americans now have diabetes, most with Type 2, in which the body doesn't produce enough or doesn't process insulin needed to convert sugar and starches to energy, according to the American Diabetes Association. This form of the disease is linked to excessive weight, putting another 79 million in the pre-diabetic category.
Diabetes sufferers have higher rates of heart disease and stroke, high blood pressure, blindness, kidney and nervous system disorders and amputations. The disease is estimated to cost the nation $116 billion a year in direct medical costs.
The diabetes association stops short of recommending surgery but says it should be considered for obese people who have other health problems not controlled with medications and lifestyle changes. The surgery, the group said, carries risks and still requires patients to adhere to significant dietary changes and life-long monitoring.
The type of surgery that seems to work is gastric bypass, which shrinks the stomach considerably and shortens the rest of the digestive system. Studies show the surgery cures diabetes in about 78 percent of patients, usually before weight loss occurs.
No one has been sure why, but a hormone called glucagon-like peptide-1, or GLP-1, has been suspected to play a role for about a decade.
In a person without diabetes, the stomach uses the hormone to warn the pancreas to make insulin when there is an increase in sugar in the blood.
People with Type 2 diabetes have a defect in how the body responds to and produces insulin in the pancreas. Increasing GLP-1 levels can help increase insulin production to levels where it can control blood sugar, and gastric bypass seems to increase GLP-1 production.
Munger and fellow researchers' studies on rats seem to show that the sugar-sensing mechanism also can be triggered in the large intestine. It's an unlikely place, because the primary site for production of the GLP-1 hormone is the small intestine.
The researchers now are trying to figure out how to trigger the mechanism without surgery.
A leading candidate, glyburide, is a drug currently used for diabetes treatment. It's cheap and can be taken orally, but can cause the pancreas to produce too much insulin, which can make blood sugar drop too low. So there are efforts to replace it.
Munger said scientists who regularly work with pharmaceuticals may be able to target the drug to the large intestine where it could prompt GLP-1 production or they may find a new drug to directly spur insulin production. First, he and fellow researchers need to show the mechanism works in humans and not just rats.
Something worked for Maker after her surgery. But an explanation was less important than addressing her diabetes before it caused more severe health problems. She already had high blood pressure, sleep apnea and acid reflux.
In addition to curing her diabetes and other health problems, she's also lost 117 pounds, and went from size 22 to size 10. She recently completed her first 5K road race.