Is Folic acid dangerous? Maybe. Definitely worth more study!

Folic Acid Supplementation has had a rough few months.

A sampling of the newest research:

From today's NY Times:
"Vital Signs - Study Raises Cancer Concerns in Big Doses of Folic Acid - NYTimes.com:

"The latest study, published in the Nov. 18 issue of The Journal of the American Medical Association, monitored the same patients through 2007. It found that 10 percent of patients who had been treated with folic acid and vitamin B 12 had developed cancer, compared with 8.4 percent of those who had not received the treatment, an increased risk of 21 percent.""

This was also reported in the LA Times:

Folic acid and cancer: New data might add to suspicion or, better, to discussion | Booster Shots | Los Angeles Times: "

Researchers in Norway analyzed data from 6,837 people with ischemic heart disease treated with folic acid, B6 and B12; folic acid and B12; just B6 or a placebo. Those treated with folic acid and B12 had higher rates of cancer, cancer deaths and deaths in general over the course of several years. Lung cancer contributed significantly to the cancer numbers."

The actual paper is from the Journal of American Medical Association:

"....Conclusion Treatment with folic acid plus vitamin B₁₂ was associated with increased cancer outcomes and all-cause mortality in patients with ischemic heart disease in Norway"

Dr. Furhman goes further referring to previous studies (smaller) that also found a relationship with folic acid and cancer. Furhman makes major efforts to say that these findings are based on synthetic folic acid and not folates in fruits and vegetables.

"Paradoxically, in people who do not take folic acid supplements there is inverse relationship between dietary folate intake and breast and prostate cancer.^14,3 Folate is an essential nutrient with vital functions. It is probable that folate levels need to be tightly regulated by the body – that the timing and dose of folate is an important determinant of whether folate has positive or negative effects. Folate's actions on DNA may prevent cancer from initiating, but may also promote the proliferation of tumor cells that may already present.¹⁵ Luckily, getting our folate exclusively from food ensures that we do not get too much. It comes naturally packaged in balance with other micronutrients and the body regulates its absorption.^9"

If that were not enough,, there is also evidence that excess folic acid during the latter part of pregnancy may lead to increase asthma risk: MedGuru citing an article in the Journal of Epidemiolgy reports that

"The researchers found that women who took folic acid supplements between 16 to 30 weeks of the pregnancy were 30 percent more likely to give birth to a child who could develop breathing problem like asthma by the time he reaches three years of age.

On the other hand, women who took the folic acid supplements prior to conception or just few weeks after conception had no such risk."

So what to do? Given the numerous tests have shown a reduction of birth defects from folic acid and those in the cancer studies were taking larger than recommended doses. As the Guardian concludes:

"If you're thinking of having a baby or are already pregnant, it's recommended that you take 400 micrograms of folic acid every day, from the time you stop using contraception until week 12 of your pregnancy. In the study, the people who developed cancer had been taking double this dose for several years.

Even so, the supplements used in the study were within the supposedly safe limit for folic acid, which was thought to be around 1,000 micrograms per day. Most people get less than this. A typical British person probably gets around 302 micrograms a day, including natural folate from vegetables, and from folic acid added to foods like breakfast cereals."

Thus, I would definitely suggest asking your doctor about it one way or the other and be sure to mention these recent studies, (S)he may not have seen them yet.