'Mediterranean'-Style Diet Best for Blood Sugar Control

Dec. 18 --

TUESDAY, Dec. 16 (HealthDay News) -- Chowing down on lentil soup and pasta seems to be the way to go if you have type 2 diabetes.

A new study found that a diet of "low-glycemic foods" -- such as beans, nuts, peas, lentils and pasta -- was superior to a high-cereal-fiber diet when it comes to lowering blood sugar and other risk factors for heart disease in people with diabetes.

"These findings fit with the general tenor of what's gone before. The trouble is that those studies tended to be considerably smaller and for shorter periods of time, and they didn't always show the effects significantly," said study author Dr. David J.A. Jenkins, Canada research chair in nutrition and metabolism at the University of Toronto and St. Michael's Hospital in Canada. "I think this certainly supports a recommendation to people that this is an extra tool in the tool kit."

"This reemphasizes what we know -- at the end of the day, the best diet is the Mediterranean-type diet: nuts, beans, lentils, fruits, vegetables," said Dr. Suzanne Steinbaum, director of Women and Heart Disease at Lenox Hill Hospital in New York City, and a spokeswoman for the American Heart Association. "The study didn't exactly call it a Mediterranean diet, but the components of it were Mediterranean."

A second study found that people who have type 2 diabetes when they are diagnosed with cancer face a greater risk of death compared to cancer patients without diabetes.

Both papers were published in the Dec. 17 issue of the Journal of the American Medical Association.

The diabetes epidemic now affects some 20 million people in the United States alone, a staggering 7 percent of the population. The condition increases the risk for heart disease, cancer and other health problems.

Although many drugs are available to control blood sugar levels, the evidence on how well they reduce the risk of cardiovascular problems isn't entirely clear. This makes a proper diet crucial to help control the disease.

For the new study, researchers at St. Michael's Hospital and the University of Toronto in Canada randomly selected more than 200 people with type 2 diabetes to follow either a high-cereal-fiber or a low-glycemic-index diet for six months. All the participants were already taking blood-sugar-lowering medications.

Carbohydrates in a low-glycemic-index diet are absorbed through the small intestine and converted to blood sugar at a slower rate than higher glycemic foods, meaning blood sugar is more stable, the researchers said.

Hemoglobin A1c (HbA1c) levels, a longer-term measure of blood sugar levels, decreased by 0.5 percent in people on the low-glycemic-index diet, compared with a decrease of 0.18 percent in the alternate group.

Those in the low-glycemic group also saw an increase in their high-density lipoprotein (HDL or "good") cholesterol of 1.7 mg/dL, compared to an HDL decrease of 0.2 mg/dL in the high-cereal-fiber group.

Although the reduction in HbA1c levels was small, the study authors speculated that, based on previous studies, this might result in a 10 percent to 12 percent reduction in cardiovascular complications.

For the second paper in the journal, researchers at the Johns Hopkins University pooled data from 23 completed studies and found that people with diabetes were 41 percent more likely to die of cancer than people who did not have diabetes. Specifically, there was a 76 percent increase in the risk of death from endometrial cancer, a 61 percent increase for breast cancer, and a 32 percent increase for colorectal cancer.

The researchers said possible explanations range from an insulin environment that contributes to tumor cell proliferation, to less-rigorous screening practices, to complications from diabetes factoring into cancer treatment decisions.

More information

Visit the American Diabetes Association for more on type 2 diabetes.

SOURCES: Dr. David J.A. Jenkins, Canada research chair, nutrition and metabolism, University of Toronto and St. Michael's Hospital; Suzanne Steinbaum, D.O., director, Women and Heart Disease, Lenox Hill Hospital, New York City; Dec. 17, 2008, Journal of the American Medical Association