No one likes to talk about prunes in public. Long the objects of jokes, prunes (dried plums) are the forgotten child when discussing the abundance of fruits and vegetables available for us to eat each day. Although the season is ending, they are still available in some farmers markets and in the grocery store.

Well, move over fiber bars, prunes deserve honorable mention. New research validates that prunes are more effective than psyllium fiber (which is found in fiber and cereal bars) in combating constipation. In a new study coming out of the University of Iowa, Satish Rao, MD, Ph.D., and colleagues recruited 40 constipated men and women, average age 38. Participants received a total of 6 grams of daily fiber from either 50 grams of dried plums (1.76 ounces, or about 5 to 6 prunes) eaten twice a day or 11 grams of psyllium (1 tablespoon, such as Metamucil) taken in water twice a day. Each regimen was followed for three weeks, with a one-week "washout" period in-between. Participants kept diaries of symptoms and their success in relieving constipation. Although both supplements increased the number of complete bowel movements, the use of dried plums produced a greater increase than psyllium. Measures of stool consistency also improved more when subjects were consuming prunes.

Almost everyone gets constipated at some time during his or her life. It affects approximately 2 percent of the population in the U.S. Women and the elderly are more commonly affected. But some people don't realize that you don't have to have a bowel movement every day. In fact, less than 50 percent of people have one bowel movement a day.

So, what really causes constipation? Here is a list of some of the triggers:

• Inadequate water intake

• Inadequate fiber in the diet

• A disruption of regular diet or routine; traveling

• Inadequate activity or exercise or immobility

• Stress

• Resisting the urge to have a bowel movement, which is sometimes the result of pain from hemorrhoids

• Overuse of laxatives (stool softeners) which, over time, weaken the bowel muscles

• Hypothyroidism

• Neurological conditions such as Parkinson's disease or multiple sclerosis

• Antacid medicines containing calcium or aluminum

• Medicines (especially strong pain medicines, such as narcotics, antidepressants, or iron pills)

• Depression

• Eating disorders

• Irritable bowel syndrome

• Pregnancy

• Colon cancer

If you or someone you know suffers from chronic constipation, you may want to ditch the fiber bar in favor of the prune. Which one is healthier? Hmmm, a dried plum or a processed fiber bar - I would always choose the most natural, hands down.

Don't forget to eat a well-balanced diet with other sources of fiber too such as legumes, and whole-grain bread and cereal (especially bran). Drink 6-8 glasses of water and other fluids a day. And last, but certainly not lease, exercise regularly.

Dr. SeAnne Safaii, Ph.D., RD, LD, is an assistant professor at the University of Idaho.