Taking folic acid supplements does not reduce the risk of developing precancerous tumors in the colon and may even increase the risk, a new study has found.
"We had great hope that folic acid would be a very cheap and effective agent to prevent large bowel adenomas. We expected that folic acid would decrease the risk for colorectal cancers, perhaps as much as 40 percent. So these results are disappointing," said Robert Sandler, M.D., a study co-author and chief of the division of gastroenterology and hepatology in the University of North Carolina at Chapel Hill School of Medicine.
In addition, the government-mandated addition of folic acid to common grain-based foods such as bread, flour and pasta may be a contributing factor to increased risk and thus research into this possibility should have a high priority, the study authors concluded.
Sandler said there is no reason for people to think that fortified foods are risky and should be avoided. At the same time, he said, there is now reason to doubt that folic acid fortification will prevent colorectal cancer, which is one of the more common cancers.
"Women who are contemplating pregnancy or in early pregnancy should continue to seek out folic acid-fortified foods and take supplements," Sandler said. "The rest of us should await more data before we change our eating patterns or before policymakers revisit food supplementation."
The study appears in the June 6, 2007, issue of the Journal of the American Medical Association. The lead author is Bernard F. Cole, Ph.D., of Dartmouth Medical School. The research took place at nine clinical centers, including UNC, between 1996 and 2004. Partial funding for the study was provided by the National Institutes of Health. Folic acid supplements provided to patients during the study were provided by Wyeth Consumer Health Care.
Previous research has shown that taking folic acid supplements significantly reduce the incidence of neural tube defects, such as spina bifida, in newborns. For this reason, the Food and Drug Administration required the addition of folic acid to many grain-based foods starting in 1998. Earlier studies also suggested that folic acid might play a role in preventing colorectal cancer.