TUESDAY, Jan. 4 (HealthDayNews) -- Conventional wisdom about constipation is often only folklore, with no basis in fact, a new German report claims.

The beliefs that fiber or water can cure constipation and that laxatives can damage the colon or become addictive are simply wrong, the researchers said. To dispel these and other misconceptions, they looked at the common beliefs about constipation and reviewed medical trials to separate fact from fiction.

"Chronic constipation is uncomfortable, but not dangerous," lead researcher Dr. Stefan A. Müller-Lissner, a professor of internal medicine and gastroenterology at Humboldt University in Berlin, said in a statement. "This might be the reason why medical doctors often do not take it seriously. There are many unproven beliefs about constipation, but most of them are not tenable upon closer investigation with scientific methods."

For example, there is no evidence that disease can be caused by the absorption of poisonous substances from stools being absorbed by the colon, according to the report in the January issue of the American Journal of Gastroenterology.

Other common misconceptions are that an elongated colon can cause constipation, or that a low-fiber diet can cause constipation. Although some patients may be helped by a high-fiber diet, many who have severe constipation may get worse when fiber intake is increased, the researchers noted.

Moreover, unless you are dehydrated, increasing the amount of fluid you drink won't cure constipation, Müller-Lissner's team said.

Perhaps most interesting is the myth that laxatives can damage the colon. According to the researchers, "It is unlikely that stimulant laxatives at recommended doses are harmful to the colon."

Although some patients with chronic constipation are dependent on laxatives, this does not mean this is the result of continuous use of laxatives. "Tolerance to stimulant laxatives is uncommon. There is no indication for the occurrence of 'rebound constipation' after stopping laxative intake. While laxatives may be misused, there is no potential for addiction," the researchers wrote.

Moreover, laxatives do not increase the risk of colon cancer or nerve damage in the colon, the researchers said.

Among older patients, constipation may be present with decreased physical activity, but the decrease in activity is not the cause of constipation, the researchers added.

Given these facts, "patients may no longer be bothered by ineffective advice regarding fiber and fluid ingestion nor threatened by the side effects of laxatives," Müller-Lissner said. "Also, unnecessary colonic resections may be avoided."

According to the American College of Gastroenterology, there are 2.5 million doctor visits for constipation in the United States each year, and hundreds of millions of dollars are spent on laxatives annually.

"This is an important article," said Dr. Benjamin Krevsky, director of gastrointestinal endoscopy at Temple University School of Medicine in Philadelphia. "It is important because there are a lot of misconceptions about chronic constipation, both amongst doctors and patients."

Krevsky noted that fiber or fluid can be part of the treatment.

In terms of laxatives, Krevsky said that modern laxatives are both safe and effective. "The laxatives we have today are different than the laxatives we had in the '40s and '50s," he stressed.

"Probably in the '40s and '50s, there were people who did get injury to their bowel from the chronic use of laxatives. But the laxatives out there today are much safer and much less likely to do that," he said.

If you have constipation, see your doctor, Krevsky advised. "Work with your doctor to find a regimen that is going to be safe and healthy for you," he said.

More information

The National Institute of Diabetes and Digestive and Kidney Diseases can tell you more about constipation.