By Alan R. Gaby, MD
On Dec. 17, there was widespread coverage in the news media of an editorial that appeared in the Annals of Internal Medicine (Annals), under the title, “Enough is enough: stop wasting money on vitamin and mineral supplements.”(1) The authors of the editorial concluded, “We believe that the case is closed — supplementing the diet of well-nourished adults with (most) mineral or vitamin supplements has no clear benefit and might even be harmful. These vitamins should not be used for chronic disease prevention. Enough is enough.” However, the editorial appears to be biased and to lack scholarship, as it is based on selective reporting and a superficial analysis of the vast and complex body research on the health effects of nutritional supplements.
The editorial focused mainly on three studies published in that issue of the Annals. The first study found that supplementing with large doses of vitamins and minerals after a heart attack reduced the recurrence rate of cardiovascular events (such as heart attack, stroke, or heart surgery) by 11 percent, compared with a placebo. (2) However, because this reduction was not statistically significant, the editorial concluded (incorrectly) that the treatment was ineffective. The failure to demonstrate that an effect is statistically significant is not the same as demonstrating the absence of an effect…
The second study in the Annals found that daily use of a low-potency multivitamin (Centrum Silver) for an average of 8.5 years had no effect on cognitive function in elderly men participating in the large Physicians’ Health Study II. (3) However, two other recent double-blind trials (which were not mentioned in the editorial) found positive effects of vitamins… recent research has shown that many elderly people need unusually large amounts of this vitamin (500 mcg per day or more in some cases) to achieve optimal vitamin B12 nutritional status. (6) The other difference is that several aluminum-containing artificial coloring agents are present in Centrum Silver (FD&C Blue 2 Aluminum Lake, FD&C Red 40 Aluminum Lake, and FD&C Yellow 6 Aluminum Lake), and these chemicals have the potential to adversely affect cognitive function… Moreover, there is evidence that long-term aluminum exposure can contribute to the development of Alzheimer’s disease.(8) The ineffectiveness of a low-potency supplement that contains extraneous and potentially harmful additives does not negate the beneficial effects of higher-potency supplements reported in other trials.
The third Annals study discussed in the editorial was a review of research examining whether vitamin and mineral supplements can prevent heart disease or cancer. (9) The editorial stated there is “no clear evidence” that taking a multivitamin can prevent cancer. However, the research review that was cited in the editorial actually found a statistically significant 7 percent reduction in cancer incidence in men, and no effect in women…
Future research should attempt to understand the differences between studies that found positive results and those that did not, in order to maximize the benefits and minimize the risks of nutritional supplements. Simply dismissing a vast body of research because the results are conflicting is not useful. The case regarding vitamins and minerals is far from closed, and the public is not well served by shallow interpretations of complex issues.