Folic Acid Supplements Cause Cancer? New Study Says Otherwise

The folic acid debate continues--at least where cancer is concerned. A new meta-analysis found that folic acid supplementation had no statistically significant effect on the incidence of cancer over the course of five years.

Among the 50,000 individuals enrolled in 13 clinical trials, 7.7 percent of those receiving folic acid developed malignancies. However, 7.3 percent of those receiving placebo also developed malignancies. These findings show that there was a insignificant 6 percent increase in cancer in participants taking folic acid supplements.

The study, reported online in the Lancet, debunks the notion that the vitamin causes a small rise in cancer.

Folic acid, also known as folate, is a vitamin that can reduce changes of birth defects--such as spina bifida--when taken in early pregnancy. Many countries, including the U.S., add folic acid to all flour.  That means it appears in products that range from baked goods to crackers.

Worries about folic acid first rose when a 2007 Canadian study showed that the incidence of colorectal cancer rose temporarily when the vitamin was added to flour in both the U.S. and Canada. One theory even suggested that folate had boosted the grown of tiny, undetected cancers and allowed them to be diagnosed earlier. This would give the impression that cancer rates had increased.

This new study, though, proves that cancer is not caused by folic acid. It gave participants doses of folate that were much higher than those in the mandatory fortification in flour. The slight increase of cancer incidence that was observed was probably the product of chance alone. The research has helped assuage fears over the use of folate in flour.