TUESDAY, Sept. 27 (HealthDay News) -- Many children in western countries suffer from chronic constipation, and when the going gets slow, fiber seems to beat all other non-drug remedies, new research from the Netherlands suggests.

A review of nine studies with 640 children up to age 18 with functional constipation, which has no known physical cause, found that fiber supplements were somewhat better than placebos at reducing kids' abdominal pain and improving frequency and consistency of stools.

Other common non-drug treatments -- including prebiotics and probiotics, which help restore the digestive tract's balance of "good bacteria," increased water intake or behavioral therapy -- were deemed to be of little use, a finding that puzzles some doctors.

"Treatments we typically use were not, in fact, proven by these studies to be effective. I find that very difficult to believe and put into practice," said Dr. Roya Samuels, a pediatrician at Cohen Children's Medical Center in New Hyde Park, N.Y., who was not involved with the research.

"Anecdotally, that doesn't really jive with what I see in clinical practice. Increasing water intake helps with the improvement of establishing normal bowel habits, and I find it hard to agree with the concrete findings of the study," Samuels added.

Study author Dr. Merit Tabbers, a pediatric gastroenterologist at Emma Children's Hospital in Amsterdam, pointed out that a lack of well-designed trials on children's constipation made it difficult to determine how credible the results really are. The results should be viewed cautiously, said the authors, noting future studies of high quality and uniform standards are needed to obtain definitive answers.

The study is published in the Sept. 26 online edition and the October print issue of the journal Pediatrics.

Constipation affects many small kids who eat lots of processed foods. Low-fiber, "white" diets, replete with bread, pasta, rice, crackers and dairy products, are mostly to blame for the 3 percent estimated prevalence of chronic constipation among children in the Western world, experts said. In addition to infrequent stools, the condition is characterized by abdominal pain and "fecal incontinence," or uncontrollable soiling caused by leaking stool.

Over time, chronic constipation may impair a child's development and disrupt psychological and social functioning, the authors pointed out.

Dr. Howard Bennett, a pediatrician in Washington, D.C., and author of It Hurts When I Poop! A Story for Children Who Are Scared to Use the Potty, said the first thing many doctors do is ask parents about a constipated child's diet and suggest either cutting back on white foods and adding fiber-rich foods and supplements, or both. Stool softeners and other gentle medications may also be recommended, he said.

"We can't force a 3-year-old or an 8-year-old to eat a prune . . . so if we cut back on cheese and highly processed foods and increase fruits and vegetables . . . we find most of these kids do better," Bennett said.

Samuels and Bennett said they recommend stimulant laxatives -- which are thought to be potentially habit-forming -- after other options are exhausted.

"By and large, we see these kids pooping," Bennett said. "Often parents won't use enough (medications) or use them long enough. Constipation is not a serious problem, but you have to take it seriously . . . or the ability to evacuate gets worse."

More information

The U.S. National Digestive Diseases Information Clearinghouse has more information about constipation.