Aspirin Doesn't Guard Diabetics Against Heart Disease

"Nutrition research is extremely complex," Shao added, "and doesn't always provide clear-cut answers. This study raises an interesting set of scientific challenges as to why the benefits found in observational studies have not been confirmed in this kind of trial."

Both studies were expected to be published in the Nov. 12 issue of the Journal of the American Medical Association and were released early to coincide with presentations on Sunday at the American Heart Association's annual scientific sessions, in New Orleans.

Other research from the meeting showed that both traditional and novel nutritional strategies could reduce risk factors for heart disease.

Drinking three cups a day of hibiscus tea (found in most commercial tea blends in the United States) lowered blood pressure over a six-week period, most significantly among those with the highest blood pressure to begin with, Diane McKay, an assistant professor at Tufts University, said during a Sunday news conference. "Even small changes in blood pressure...when seen in large population studies, will effectively reduce the risk of certain mortalities," she said.

Other research showed that three servings of non-soy legumes such as beans and chickpeas lowered total and LDL ("bad") cholesterol, according to a meta-analysis of previous studies. "My Pyramid suggests three cups weekly of dry beans and peas, or legumes, and we are very, very far behind," said Dr. Lydia A.L. Bazzano, of Tulane University in New Orleans.

Two additional studies found that eating high-fat diets increased left-ventricular mass, which is linked to left ventricular dysfunction, a predictor for heart failure, while diets high in fruits, vegetables and fish had the opposite effect, said researchers at Drexel University School of Public Health in Philadelphia.

More information

Visit the American Diabetes Association for more on the link between type 2 diabetes and heart disease.