(HealthDay News) — Here’s the latest word on whether a diet rich in fiber helps prevent cancer of the colon and rectum: Probably not.
While several studies have found a lower risk of colorectal cancer for people who have a high intake of dietary fiber, a new study that combined the results of 13 studies including more than 725,000 people found no overall protective effect when all risk factors were taken into account.
A first look at the data did find a 16 percent lower incidence of the cancer in the 20 percent of people with the highest fiber intake. But then the researchers began compensating for other risk factors — such as multivitamin use, folate intake, red meat consumption, milk and alcohol intake.
As a result, “we did not find support for a linear inverse relationship between dietary fiber intake and risk of colorectal cancer,” the researchers wrote.
The study results appear in the Dec. 14 issue of the Journal of the American Medical Association.
So, what about those prior studies suggesting fiber had a protective effect?
“In general, most previous studies have been inconsistent,” said Yikyung Park, lead author of the journal report. She led the study while at the Harvard School of Public Health and is now a visiting fellow at the National Cancer Institute.
“To date, this is the largest study and we found that dietary intake of fiber did not lower risk,” she said.
But this report is certainly not the last word on the issue, Park added. “This is still a very active area of research,” she said. “Clearly, more studies are needed.”
The real problem in reaching a definite conclusion is that “fiber” is a vague term, explained Dr. John A. Baron, professor of medicine at Dartmouth Medical School, who wrote an accompanying editorial in the journal.