Bergen, Norway—The vitamin B complex is arguably one of the industry’s best-selling basic vitamins, particularly with many women of childbearing age taking folic acid. Results from a study published in the Journal of the American Medical Association, however, claims shoppers should be careful when taking this vitamin. But, should they?

From 1998 through 2005, a group of Norwegian investigators gave 6,837 heart disease patients B vitamins or a placebo. One group took folic acid (0.8 mg/d) plus vitamins B12 (0.4 mg/d) and B6 (40 mg/d); the next took folic acid (0.8 mg/d) plus vitamin B12 (0.4 mg/d); the third took just vitamin B6 (40 mg/d); and the last group took a placebo. Follow-up continued through 2007.

The data on the folic acid plus vitamin B12 group was well publicized in the mainstream media: 10% of this group developed cancer (mostly of the lung) of which 4% died, and 16% died from other causes. No such effects were associated with B6. The link between these two B-vitamins and cancer, however, may not be as strong as the apparent cancer–smoking link.

In a written statement, Andrew Shao, Ph.D., vice president of scientific and regulatory affairs for the Council of Responsible Nutrition noted that 94% of those who developed cancer were present or former smokers. “For years, the vast body of scientific evidence has shown that individuals who have smoked at any point in their lives are at a significantly increased risk of developing lung cancer,” he stated.

He also pointed out that though mandatory folic acid fortification has been in effect in the United States since 1998, lung cancer incidence has dropped over the past 20 years. Shao added, “It is inappropriate at this point to reach firm conclusions based on such limited data, especially in the face of vast evidence showing benefit for folic acid supplementation.”

Another flaw, according to Daniel Fabricant, Ph.D., vice president of scientific and regulatory affairs at the Natural Products Association, is that the test subjects were not in optimal health. In fact, many were taking beta-blockers, statins and other drugs, “yet there are no numbers, no analysis on the effects these interventions may have on the incidence of cancer. There is no adjustment of the baseline effect for these interventions, yet the authors adjusted the baseline for smoking, age and sex, which are all factors in the development of cancer. We have no way of determining these factors’ impact on this study as they just decided to leave that out, like ordering off of an a la carte menu.” The bottom line: these results couldn’t cancel out the previous, proven benefits of folic acid on health.

Published in WholeFoods Magazine, January 2010