Folic Acid Fights Colon Cancer

Supplements May Help Those at Risk

Medically Reviewed by Gary D. Vogin, MD
From the WebMD Archives

July 19, 2002 -- Taking folic acid supplements may reduce the risk of colon cancer in people who are most likely to get the disease. A new study shows regular supplementation of folic acid (found naturally in foods as folate) can reduce abnormal cell activity in the colon, which is an early sign of colon cancer.

The importance of a healthy diet in preventing colon cancer has been debated a lot lately due to the results of several conflicting studies. Previously, it had been thought that fruits and vegetables helped reduce colon cancer risk by virtue of their fiber content alone. But some newer studies have suggested that fiber intake has little effect on preventing colon cancer.

However, researchers say not getting enough fruits and vegetables in your diet has also been found to increase the risk of colon cancer. That means there may be other ways in which the nutrients in fruits and vegetables, such as folate, protect against the disease.

That prompted a group of Irish researchers from the Institute of Clinical Science at Royal Victoria Hospital in Belfast to measure the effects of folate supplementation on a cell proliferation process that is believed to be a precursor to colon cancer. Their findings are published in the July issue of Gut.

For the study, 11 people who had a history of recurrent precancerous growths were divided into two groups. One group was given 2 mg of folic acid per day for three months and the other a placebo.

At the start of the study, there was no difference between the two groups. But at the end, researchers found that abnormal cell activity dropped significantly in the group that received a daily dose of folic acid. But these potentially dangerous activity levels remained unchanged in the group that did not receive supplements.

When the supplements were stopped, the cellular activity began to return to pre-study levels in the folic acid group. Researchers say these findings suggest that folate seems to reduce the risk of colon cancer in susceptible people by repairing cellular damage after it has occurred.

The study authors say if more studies confirm these results, folic acid supplementation may be a valuable new way to lower the risk of colon cancer in people at high risk for the disease. But they caution that folic acid supplements may be harmful for people who have advanced cancer, are taking drugs for epilepsy, or are vitamin B-12 deficient.