The Natural Products Association (NPA) and the Council for Responsible Nutrition (CRN) have both voiced outrage over the publication of “Cancer Incidence and Mortality after Treatment with Folic Acid and Vitamin B12” in the 11/19/09 issue of JAMA. The leading researcher on this study, Dr. Marta Ebbing of Norway, is quoted as saying, “Folic acid fortification and supplementation may not necessarily be as safe as previously assumed.

In response, Andrew Shao, Ph.D., vice president of scientific and regulatory affairs at CRN, declared: “The real headline of this study should be that smoking increases the risk of lung cancer…” .

Daniel Fabricant, Ph.D., NPA’s vice president of scientific and regulatory affairs, said: “[T]wo flawed studies are combined to yield one larger flawed study. This does not seem to be in the best interest of medical science or public health”.

Among the numerous flaws in the research are:

Both of the trials in this study were designed to assess the effects of folic acid and B12 on cardiovascular disease, not on cancer.

Between 2001 and 2005, as people started taking folic acid, the United States actually saw a decrease in cases of cancer. According to CRN, “It is inappropriate to reach firm conclusions based on such limited data, especially in the face of vast evidence showing benefit for folic acid supplementation.”

Most of the subjects in both trials were taking beta-blockers and statins; some were taking ACE inhibitors and diuretics. The study fails to analyze how these combinations of drugs relate to the risk of cancer.

Design flaws caused one of the two trials to be terminated early.

The factorial design of the other trial may have been too complex.

ANH USA

Dec 2009
JAMA Publishes Flawed Studies Linking Folic Acid and Vitamin B12 to Cancer