Too Much Folic Acid May Cause Cancer

Over the past couple decades, folic acid has been largely heralded as a wonder vitamin. In the 1980s, studies began to show that folic acid might help prevent some cancers. Taking the vitamin has also been linked to reduced birth defects. In fact, since cereals and grains fortified with folic acid began hitting the market in the 1990s, rates of birth defects such as spina bifida and anencephaly have dropped by as much as 50 percent.While no one disputes that pregnant women should be taking folic acid, new studies are indicating that too much folic acid may help spur the growth of certain types of cancer.

Studies show that the same mechanism that helps fight cancer may also be accelerating the growth of cancer cells once they begin to form in the body. The benefits of folic acid stem from the vitamins ability to help the body manufacture and maintain new cells. Unfortunately, this benefit seems to translate to cancerous cells as well. This is partly why antifolate drugs are used to treat cancer.

In several animal studies, it was concluded that folic acid accelerated the formation of cancer once normal cells became locked on a path to become cancerous.

So if too little folic acid is not healthy, and too much folic acid isn’t either, then what’s the right amount that people should be taking? Researchers are still investigating this. However, most experts presently recommend a daily intake of approximately 400 micrograms. For pregnant women, that number increases to 600 micrograms.

Unfortunately, with the wide range of cereals, breads and snack bars on the market that are fortified with folic acid, individuals are at a risk to consume much more than 400 micrograms each day. Multivitamins also often over deliver on the amount of folic acid present in each daily dose.

This overdosing may have dramatic consequences. In one study, 1,000 people who had developed precancerous colon polyps were given a daily 1-milligram folic acid supplement – an amount 2.5 times greater than the recommended daily dosage. Years later, it was discovered that these people were more than twice as likely to develop three or more new polyps.

Though no clear numbers have been offered as far as healthy folic acid intake rates, Marian Neuhouser of the Fred Hutchinson Cancer Research Center in Seattle suggest “not to get more than 1,000 micrograms” a day.

Resources:

http://www.chicagotribune.com/features/chi-090607folicacid-story,0,868233.story

http://www.latimes.com/features/printedition/health/la-he-folate11-2009may11,0,1923701.story