In 1998, the United States began adding folic acid to flour products used in breads, cereals and pastas. The goal was to reduce serious birth defects, such as spina bifida. There has been some concern, though, that folic acid could increase cancer risks.
A thorough analysis of recent research on folic acid found no connection between the B vitamin and increased cancer risks.
Folic acid is the synthetic version of folate, which is found in beans and green vegetables. Everyone needs the vitamin to make and repair DNA when cells divide. There has been concern that this activity may play a role in the development of cancer, though such an association has never been proven.
Robert Clarke, FFPH, FRCP, from the University of Oxford, UK was one of the lead authors of the study.
Clarke’s team reviewed all large randomized trials studying folic acid – with and without other B vitamins – that were conducted through 2010.
Here’s what the review of previous studies uncovered:
- People who took folic acid for five or fewer years were not significantly more prone to cancer.
- Among the 1,907 individuals who took folic acid, 7.7 percent developed cancer compared with 7.4 percent of the 1,809 individuals who took a sugar pill (placebo).
- People who took even the highest amounts (40 mg a day) of folic acid did not have significantly higher incidence of cancer than those who didn’t take the vitamin.
- Individual cases of breast, colorectal, lung, prostate and other types of cancer were not significantly different among the two groups.
- The risk of cancer did not increase among people who took folic acid for longer periods of time.
The authors wrote, “Both the hopes for rapid cancer prevention and the fears about rapidly increased cancer risk from folic acid supplementation were not confirmed by this meta-analysis of the trials of folic acid supplementation.”
The researchers noted, “Nationwide dietary fortification involves doses of folic acid that are an order of magnitude lower than the doses studied in these trials."
Clarke added a cautionary note. “It remains to be seen whether any beneficial or harmful effects on cancer incidence will eventually emerge with even longer treatment or follow up."
Results from this study were published January 24 in The Lancet. The research was funded by the UK Food Standards Agency.