For a long time, cancer researchers were so focused on the powerful antioxidant vitamins A, C, and E that they sort of forgot about the B vitamins. Recently, though, folic acid has been getting a lot of attention for its role in preventing cancer of the colon and cervix—and maybe for preventing other cancers as well.

Folic Acid Helps Prevent Colon Cancer

Recent studies show that people with low folic acid levels are more likely to get colon cancer. If you’re a woman and get a lot of folic acid in your diet, for instance, your chances of colon cancer are sharply lower—by as much as 60 percent. (For some reason, this doesn’t work as well for men.)

People with ulcerative colitis (UC), a serious chronic disease of the large intestine, have an increased risk of getting colon cancer—and they also often have low folic acid levels. For many patients, the reason is that the drug sulfasalazine, which helps UC a lot, also blocks their uptake of folic acid. Recent studies show that UC patients who take 1 mg a day of extra folic acid cut their chances of colon cancer nearly in half. If you have ulcerative colitis, discuss folic acid supplements with your doctor before you try them.

Preventing Cervical Cancer

Women with cervical dysplasia may later develop cancer of the cervix, especially if the problem isn’t detected and treated early on. Many women infected with human papillomavirus (HPV) have cervical dysplasia. Women who smoke are more likely to have cervical dysplasia, probably because smokers have low folic acid levels.

Recent studies have shown that women with HPV and low folic acid levels were five times more likely to have cervical dysplasia. Other studies suggest that minor cervical dysplasia can be effectively treated with large doses (more than 5 milligrams daily) of folic acid. This is not something you should do on your own, however. If you have cervical dysplasia, discuss all your treatment options with your doctor.