The two studies looked at a large-scale clinical trial called the Physicians Health Study, in which two groups of people were assigned to take either a multivitamin or a placebo for between 5 and 12 years. In one study, the authors were looking at whether those taking multivitamins showed signs of reduced cognitive decline compared to the placebo group, and in the second, the authors wanted to know whether the multivitamins could reduce the risk of heart attacks, strokes, and other cardiovascular problems in people who'd already suffered heart attacks.
The conclusion from both studies? Multivitamins may help, but most likely, you're just throwing money down the drain. In neither case did the multivitamin takers see much of a benefit over the placebo group. An accompanying editorial, titled "Enough Is Enough: Stop Wasting Money on Vitamin and Mineral Supplements," concluded, somewhat bluntly, "we believe that the case is closed—supplementing the diet of well-nourished adults with (most) mineral or vitamin supplements has no clear benefit."
More from Rodale News: What Doctors Think of Multivitamins
So should you ditch your multivitamin? Mark Moyad, MD, MPH, Jenkins Director of Complementary and Alternative Medicine at the University of Michigan Medical Center, says not so fast. He points out that the clinical trial used in both studies, the Physicians Health Study, a randomized clinical trial, which is considered the gold standard of scientific research, did find a small but statistically significant 8 percent drop in cancer rates, a figure made even more significant by the fact that the doctors in this study were what he called "freakishly healthy" to begin with. "I don't know of a drug or supplement that's been in any larger study that suggests a statistically significant reduction in cancer. That's very positive."
So to say that you should toss your multivitamins because they don't prevent cognitive decline or heart problems, even though they may slow cancer rates, is to throw the proverbial baby out with the bathwater. "We're not expecting multivitamins to cure everything under the sun," he says. "We've had one major study, that was in men taking Centrum Silver, that seemed to slightly reduce risk of cancer. Even the researchers of that study said that, if anything, this shows that using a multivitamin that's cheap may have a benefit."
The bigger problem, Dr. Moyad says, is that supplement doses have gotten out of control in recent years, and healthcare practitioners are recommending these megadoses with no concrete evidence that they work. "A higher dose has never been better in the drug world," says Dr. Moyad, who is also the author of The Supplement Handbook. "If you look at the multivitamin used in the study, it had 4 milligrams of iron, 60 milligrams of vitamin C, and 400 IU of vitamin D. That equates with a children's product today."
And that's his point: He now recommends that his adult patients take children's products, he says, because those low-dose multivitamins are all most people need to stay healthy. "Less is more," he says. "The benefit may be small, but it's good insurance." (Nonetheless, he says, Centrum Silver, the supplement used in the Physicians Health Study, will also work if you don't want to walk out of a drugstore with a box of candy-colored Flinstones characters.)
Here are a few other things to keep in mind when shopping for multivitamins:
• Pay attention to quality. In addition to megadoses of nutrients, tests on some supplements have revealed that they're carrying a host of unwanted, even unhealthy, ingredients that could do more harm than good. The Food and Drug Administration (FDA) has found everything from lead to cancer-causing preservatives in cheap supplements, so it's important to look for an independent stamp of quality assurance, such as ConsumerLabs.com–certification, or for products bearing either the U.S. Pharmacopoeia's USP Verified Dietary Supplement or NSF Certified Dietary Supplement seals.
• Talk to your doc. There are certain populations—like pregnant women, elderly adults, and people taking medications that can interfere with nutrient absorption—that clearly benefit from taking multivitamins, says Dr. Moyad. But if you don't fall into that camp, ask your doctor during a regular checkup if you might benefit from a multivitamin; it may be that you need just one or two vitamins that you can get independently, such as vitamins D and B12, which are difficult to get from even the healthiest of foods.
More from Rodale News: Why Supplements Are Bad For Your Brain
• Beware excess copper and iron. These two metals exist in nearly all multivitamins and sometimes at levels that can lead to cognitive problems and damage to the neurons in your brain. Opt for supplements free of these metals.