The Dark Side of Your Multivitamin

Americans sure do love their supplements. Every year, we spend a whopping $20 billion on them. But if you think all that cash is going to buy you a longer life, think again. A new study in last week’s Archives of Internal Medicinesuggests that somevitamins and supplements may actually shorten your life.
In the study, researchers used information from 40,000 women who filled in questionnaires several times over the last 22 years. They answered questions about all sorts of health issues, including supplement use.
Matching this data to records from the state health registry and the National Death Index, the researchers identified seven vitamin and mineral supplements that actually seemed to be hastening death. Those include vitamin B6, folic acid, iron, magnesium, zinc, copper, and even your innocent-looking multivitamin.
Some of them only slightly increased the risk of death during the study period. For example, multivitamins nudged it up by 2.2 percent. Others, however, were more substantial: Copper, for example, increased the risk of death by about 18 percent.
These results don’t just apply to the fairer sex, says study leader Jaako Mursu, PhD, of the University of Eastern Finland and the University of Minnesota. Lots of previous supplement use studies that included men have shown the same thing: If you don’t have a documented nutritional deficiency, taking extra vitamins and minerals doesn’t seem to help, and it may even harm.
So what should you do to keep your multivitamin from sending you to an early grave? Here are a few tips:
• Know your dosage. Mursu says that anything—even water—can be hazardous in huge quantities. Supplements usually contain megadoses of many vitamins and minerals that you’d never find in food. Know the effective dosage for a particular vitamin or mineral before buying the supplement that delivers the highest level available.
• Eat food, not supplements. They're called "supplements" for a reason. "Usually, what we advise is to eat a lot of fruits and vegetables and whole grains," Mursu says. Whole foods are packed with more than enough vitamins and minerals (in addition to other important components, like fiber), in combinations that appear to be far more beneficial than those in vitamin pills. Eating lots of different foods means you get the whole complement of nutrients without ever setting foot in a supplement store.
Also, food usually contains vitamins and minerals in vastly different forms and combinations than those found in supplements—all potential reasons why popping a pill for your nutrients might not be the best plan. “If you’re not allergic or don’t have a specific reason, don’t exclude anything” from your diet, Mursu adds. “You can’t go wrong with the idea that if you eat plenty of plant food and minimize processed food, nutrient intake will be high enough for most people.”
• Pay attention to quality. In addition to megadoses of nutrients, tests on some supplements have revealed that they're carrying a host of unwanted, and 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 some seal of quality before plunking down money on supplements. Look–certified products, or those bearing either the U.S. Pharmacopoeia’s USP Verified Dietary Supplement or NSF Certified Dietary Supplement seals. These verify that vitamins and supplements are free of contaminants, that they deliver what their labels claim, and that the manufacturers comply with the FDA’s good manufacturing practices.