Folic acid may ward off colorectal cancer

New research hints that a suboptimal intake of folic acid may play a role in the development of Colorectal cancer, which points to a possible role for folic acid supplementation in colorectal cancer prevention.

In individuals with colorectal adenomas - polyps that can be precursors to bowel cancer - folic acid supplementation reverses so-called "DNA hypomethylation," investigators report.

DNA methylation is a process used by healthy cells to deactivate certain genes, but which tends to spin out of control in tumor cells.

Low folate status may increase the risk of malignancy by inducing DNA hypomethylation and altering the expression of certain genes.

In their study, investigators tested the theory that folic acid supplementation (400 micrograms per day) increases DNA methylation in colorectal tissue in 31 patients with colorectal polyps.

Following folic acid supplementation, folate levels rose significantly, as expected, and, confirming their theory, folic acid supplementation led to increases in DNA methylation in colonic tissue.

"Although the statistical effect was marginal, the present study is the first to report an increase in DNA methylation in subjects with adenoma using a physiological dose of folate for a relatively short intervention period," Dr. Maria Pufulete from King's College London and associates write in the medical journal Gut.

The study findings, they say, support the view that an inadequate intake of folate may play a role in colorectal cancer.

Commenting on the findings, Dr. John C. Mathers from the University of Newcastle, Newcastle upon Tyne, UK, says it will be important to build on these novel observations to determine optimal intakes of folate to minimize the risk of bowel cancer.

He warns, however, that the impact of an increased supply of folic acid in a population at risk for bowel cancer requires careful consideration because animal studies have suggested that folate may promote the growth of tumors.

SOURCE: Gut May 2005.