Peas and beans, long favorites of nutritionists, are even better for you than once thought, researchers at the University of Illinois at Urbana-Champaign have found. Besides being a good source of non-animal protein, legumes also are a great source of dietary fiber and a related substance called resistant starch, the scientists report in the journal Nutrition.

Resistant starch passes through the stomach and small intestine undigested. In the colon, it is digested along with dietary fiber to produce fatty acids with anti-cancer properties, researchers found.

"With their protein, fiber and resistant starch, legumes offer good nutrition, said George Fahey Jr. a university researcher.

"Until now, we never knew legumes had so much of their starch in the form of resistant starch."

As an example, the food scientists found that black beans consist of more than 40 percent dietary fiber, and more than 60 percent of their total starch is the resistant form.

Another plus for legumes, Fahey said, is they usually are eaten after minimal processing.