Supplement Didn't Seem to Impact Cancer Risk

Cancer incidence not affected by folic acid supplementation

(RxWiki News) Folic acid is known to help prevent birth defects. The vitamin has had mixed reviews when it comes to cancer prevention, though. So does taking folic acid supplements reduce your risks of common cancers?  

Taking folic acid supplements did not affect cancer risks, a new analysis of previous research has concluded.

After looking at studies involving nearly 50,000 people, researchers said folic acid did not make a difference when it came to cancers of the large intestine, prostate, lung, breast or any other specific site.

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Researchers from around the world, led by Stein Emil Vollset of the Norwegian Institute of Public Health and University of Bergen in Bergen, Norway, reviewed a total 13 different trials which looked at links between folic acid and colorectal cancer and heart disease.

“Folic acid (also known as folate or vitamin B9) is an essential vitamin that is involved in numerous important cell functions including normal cell division and growth, and the production of red blood cells,” Brian D. Lawenda, MD, clinical director of Radiation Oncology at 21st Century Oncology (Las Vegas), told dailyRx News.

“There have been some promising studies which have found that higher levels of folic acid intake (through supplements or diet) are associated with a lower risk of developing various cancers. Unfortunately, these results have been contradicted by others which have reported either no effect or an increased risk of cancers with higher levels of folic acid intake,” said Dr. Lawenda, who is an Integrative Oncologist, blending traditional treatment options with the best of the evidence-based alternative medicine.

For this study, researchers performed a meta-analysis of all trials completed before 2011 that compared folic acid versus placebo. Each of the studies analyzed lasted at least one year, included at least 500 participants and recorded data on cancer incidence.

A total of 49,621 people were involved in these trials, 10 of which looked at folic acid as prevention of heart disease and three of which had patients with abnormal colorectal growths.

Participants were randomly assigned to receive either a folic acid supplement or a placebo (sugar pill). The daily doses of folic acid ranged from 0.5 mg to 5 mg, with the exception of one trial with a daily dosage of 40 mg. Participants were followed for just over five years.

People who took folic acid supplements had statistically the same number of cases of cancers as those in the placebo group. There was no difference between the groups in the incidence of colon, prostate, lung, breast or any other site specific cancer, the study found.

“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 authors wrote.

Dr. Lawenda pointed out that results in reports that combine patients from numerous different studies offer only limited insight.

“Future studies will hopefully help us answer whether dietary intake (through food sources) of folic acid and/or longer term intake will have any impact on cancer risks,” he said.

This report appeared in the January 25 issue of The Lancet.

Study funding came from the British Heart Foundation, Medical Research Council, Cancer Research UK and Food Standards Agency. No conflicts of interest were reported.

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Review Date: 
March 27, 2013