I had to smile when I read Newsweek reporter Sharon Begley’s column this week. It’s her take (justified rant?) on Tuesday’s publication of a rigorous double-blinded randomized controlled study that has finally debunked the often-touted-but-never-proven idea that taking folic acid and B12 supplements lowers the risk of heart attacks and stroke.
For I share her exasperation.
“When will we ever learn?” writes Begley. “Over and over, experts tell us, and the media reports, that people who engage in behavior X (let’s say it’s making paper dolls in their spare time) have a lower rate of disease Y (heart attacks, say) than people who do not make paper dolls. Ergo, conclude the experts and the press, making paper dolls prevents heart attacks. Stated this way, it’s the height of absurdity. But that ‘logic’ has fostered more useless and even harmful health advice than almost anything this side of homeopathy. Its latest victim: taking folic acid to decrease your blood levels of homocysteine, an amino acid in the blood, and thus of heart disease.”
Begley even takes her own publication to task for running articles (including a 1997 cover story) that “jumped on the homocysteine bandwagen” and recommended readers consume folic acid and B vitamins to ward off heart disease.
“I hope none of you took this advice, not because it’s dangerous,” she writes, “but because it’s useless.”
And, indeed, the current study, which was published in the Journal of the American Medical Association, underscores how useless that information has been. Researchers followed more than 12,000 British heart-attack survivors (men and women, aged 18 to 80) as some downed supplements containing 2 milligrams of folic acid and 1 milligram of B12 daily for six to eight years and others took a placebo. Yes, the supplement-taking participants’ homocysteine levels had dropped by the end of the study. But that turned out to be a “so what?” result. For the drop had “no beneficial effects on cardiovascular disease,” the researchers concluded. Those taking the supplements experience no fewer heart attacks. No fewer strokes.
These findings come on the heels of a large review published earlier this spring that analyzed 13 previous clinical trials involving folic acid supplements and strokes. That review also found no evidence that taking the supplements helped prevent those catastrophic cardiovascular events. And last year a Cochrane Collaboration review of eight randomized clinical trials concluded that treatments aimed at lowering homocysteine levels did nothing to reduce the risk of stroke, heart attacks — or, for that matter, deaths from any cause.
“Yet lowering homocysteine has been, and in some quarters remains, a pillar of cardiac health,” writes Begley. “(Just Google ‘lower homocysteine levels.’) [I did: 337,000 results in .49 seconds.] How could so many be so wrong? Because of the paper-doll fallacy. Studies that simply observe two groups of people to see how they differ can’t distinguish correlations from causes: people who make paper dolls may be healthier, but it is not because they make paper dolls.”
“[I]t isn’t clear yet why the observational studies — high homocysteine equals higher risk of cardiovascular disease — were misleading,” Begley concludes. “It might be that high levels of homocysteine are a marker for the real culprit, and fixing it leaves that culprit unscathed. But you have to wonder how many more times we — the press as well as supposed experts — will make the mistake of basing health advice on observational studies.”