There is good news for people with diverticular disease who have been told to avoid nuts, corn, and popcorn. Instead of increasing the risk for the digestive disorder diverticulitis, as has long been suspected, these foods may actually lower risk of the condition, according to findings from the first large study to address the issue.

About a third of Americans will develop small pouches of the colon, a condition known as diverticulosis, by the time they reach age 60; two-thirds have the pouches by age 85.

Most people with diverticulosis experience no symptoms, but as many as one in four will develop diverticulitis, a potentially serious condition characterized by intense pain in the lower, left side of the abdomen and possible nausea, vomiting, cramping, and bleeding, according to the National Institutes of Health.

Since at least the 1950s many doctors have advised patients who have diverticular disease to restrict nuts, corn, popcorn -- and even vegetables with seeds like tomatoes -- on the theory that the indigestible components of these foods would lodge in the pouches, causing symptoms.

"It is not exactly clear where this idea came from because there are no studies showing this to be the case," researcher Lisa L. Strate, MD, MPH, tells WebMD. "It just became a part of medical lore." Men who ate nuts, corn, or popcorn frequently were found to have no greater risk for developing diverticulitis or diverticular bleeding than men who rarely ate the foods.

In fact, men who ate nuts at least twice a week had a 20% lower risk of diverticulitis than men who ate nuts less than once a month; men who ate popcorn at least twice a week had a 28% lower risk. "For decades people have been told that eating these foods increases complications associated with diverticular disease, but our results suggest they don't," Strate says.