How to Buy the Best Multivitamin

Written by: Erin O'Donnell

Taken daily, multivitamins protect your health. Our experts tell you how to choose the right supplement.

If you only have time today to do one thing to protect your health, take a multivitamin. A Harvard study published last year in the Journal of the American Medical Association reviewed 30 years of supplement studies and concluded that when taken daily, multivitamins can help you prevent diseases including heart disease, cancer, and osteoporosis.

Experts agree that they're an effective and inexpensive way to stay well. To help you choose a high-quality vitamin that meets your needs, we gathered this advice from six supplement experts.

Demand 100 Percent of Vitamins

When you look at the "Supplement Facts" panel on the label, you should see at least 100 percent of the daily value of some important vitamins, especially vitamins B6, B12, C, D, and E and folic acid. (The "daily value" is what the government calls its recommended daily dose.) Vitamins B6, B12, and folic acid appear to reduce heart disease risk; vitamin C boosts immune function and may protect against heart disease; vitamin D protects your bones and may prevent cancer; and vitamin E could cut prostate cancer risk. In fact, a few of these nutrients are so important that for optimal health some experts suggest you take more than 100 percent; for details, see related article, "How to Pick the Formula You Need."

Be Mindful of Minerals

While you should expect your multi to offer 100 percent or more of certain vitamins, this doesn't necessarily hold true for minerals. If you do see 100 percent of the daily value of most minerals on the label, you'll probably also see that you need to take several pills a day. That's because some minerals, like calcium and magnesium, are so bulky that manufacturers could never fit your entire daily dose in one pill, says David Schardt, senior nutritionist for the Center for Science in the Public Interest, a nutrition watchdog group in Washington, D.C. If you choose a one-pill-a-day multi, it won't have all the minerals you require. You'll need to take additional calcium and magnesium supplements to get 100 percent.

Don't Overdo A

The vitamin A in multivitamins usually comes from two substances: retinol, sometimes called preformed vitamin A, and beta carotene, a plant chemical your body converts to vitamin A. One of these substances, retinol, has come under scrutiny. Recent studies found that people who consumed around 5,000 IU of retinol daily had reduced bone density or increased hip fracture risk. The problem is that most multivitamins contain 5,000 IU of vitamin A, and a large part of that usually comes from retinol.

What should you do about vitamin A? Jane Higdon, Ph.D., research associate at the Linus Pauling Institute at Oregon State University in Corvalis, Ore., recommends that you choose a supplement that contains no more than 5,000 IU of vitamin A and provides at least 50 percent of that amount as beta carotene, which does not pose the same osteoporosis risk as retinol.

Other experts say that to play it safe, you should choose a multi with 100 percent as beta carotene and no retinol.

If you're a smoker or are regularly exposed to cigarette smoke, studies show that synthetic beta carotene could increase your lung cancer risk. (Natural beta carotene hasn't been tested, but it could cause the same problem.) In that case, you may want to take separate supplements instead of a multi so you can skip vitamin A altogether.

Watch Out for Iron

If you're a man or menopausal woman, take a multivitamin that's iron-free. Some studies suggest that too much of this mineral could increase your risk of heart disease and certain cancers. The only people who need iron include women who menstruate (and shed excess iron through monthly periods), vegetarians (who may not get enough iron from their diets), and endurance athletes (who may experience minor bleeding in their digestive tracts). If you think you're iron deficient, ask a doctor to test you before you supplement. If you menstruate, choose a multi that contains up to 18 mg of iron.

Consider Special Needs

Depending on who you are, you may need extra amounts of certain vitamins and minerals.

If You're Older than 50: You could require extra amounts of vitamin B12. This crucial nutrient protects your heart by helping to lower unsafe homocysteine levels, and a deficiency can trigger irreversible nerve damage. The daily value of B12 is 6 mcg, but many older adults lack enough stomach acid to absorb the vitamin efficiently, says Jeffrey Blumberg, Ph.D., professor of nutrition at Tufts University in Boston. For that reason you may want to pick a multi that provides 25 to 100 mcg of B12 daily.

If You're a Man: Make sure you get enough selenium to reduce your risk of certain cancers. The daily value is 70 mcg, yet a 1996 study published in the Journal of the American Medical Association showed that taking 200 mcg daily dramatically reduced the risk of lung, colorectal, and prostate cancers. A recently published update looked at additional data from the 1996 study and found that women received no cancer protection from selenium supplements.

Steve Austin, N.D., a Portland, Ore.-based naturopathic physician and co-author of The Natural Pharmacy (Prima, 2000), recommends that men choose a multi that contains 200 mcg of selenium (preferably yeast-based selenium, the form used in studies) or take a separate supplement that provides 200 mcg. Women shouldn't bother with more than the daily value, Higdon advises.

Seek Out Simplicity

Some supplement manufacturers include herbs like black cohosh or nonessential nutrients like para-aminobenzoic acid (PABA) in their multivitamins. Austin believes you're better off choosing a supplement that doesn't include these extra ingredients. "Often the herbs that are added are very important herbs, but if you look at the amounts in a multi, they're never significant enough to make a difference," he says. The same goes for nonessential nutrients like PABA (considered by some to be part of the vitamin B complex). The research so far suggests that the trivial amounts of PABA and other nonessential nutrients in most multivitamins are certainly harmless, but most likely useless, Austin adds.

Find the Small Print

Skip any multivitamin that doesn't have an expiration date or lot or batch number on the label. The expiration date matters because "vitamins and minerals can degrade over time," Blumberg says. You're more likely to get the nutrient amounts listed on the label if you use your multi before it expires. Don't buy a bottle that has more pills than you will take before the date passes, he adds.

Lot or batch numbers mean that the company tracks the supplements it makes, explains Paul Domp, N.D., a naturopathic physician who reviews the quality of all supplements used or sold at the Bastyr Center for Natural Health in Seattle. These numbers are one sign of a careful company; they allow the company to recall a supplement quickly if there's a problem with the product, like contaminated ingredients, he says.

Domp also recommends that you search the label for a statement of what the multivitamin doesn't contain, like artificial colors, binders, corn, dairy, eggs, fillers, hydrogenated oils, preservatives, soy, sugar, or wheat. Allergies and sensitivities to these substances are common. If you have a sensitivity, these ingredients could cause inflammation in your digestive tract, possibly reducing the nutrients you absorb, Domp says. If you're a vegetarian, look for a statement that the supplement is gelatin-free.

Get a Form that Suits You

Multivitamins come in several forms. The best for you depends on your needs, Domp says.

Tablets and capsules, the most common forms, are convenient to carry and take. Capsules tend to be smaller than tablets, so they're easier to swallow, but you may need to take several a day to get the same amount of nutrients found in one tablet. On the other hand, although tablets hold the most nutrients, they require binders to hold them together, so they may not break down as easily as capsules.

People with poor digestion or those who can't swallow big pills may do better with liquid or powdered multivitamins (which you mix with water and drink). These don't require as much work from your body to digest, Domp says.

Chewables are another option if you can't swallow pills, but they often contain lots of sugar to make them palatable. Domp advises that you look for chewables sweetened with fructose or stevia.

The bottom line? Choose the form that's easiest for you to take every day. Studies show that you need to take a multi daily for years to protect against ailments like heart disease, says Annette Dickinson, Ph.D., vice president of scientific and regulatory affairs at the Council for Responsible Nutrition, a supplement trade group in Washington, D.C.

Look for Quality Marks

Finding one of the following four quality seals on your multi means it meets high product standards. But you shouldn't necessarily ignore bottles without a seal, because these quality programs are relatively new and only an estimated 50 companies that sell multis have undergone the testing to earn a seal. Also, a company can pass one of these certification programs but not use the mark on its label.

These four organizations or companies offer quality marks:
NNFA: A seal from the National Nutritional Foods Association (NNFA), a nonprofit trade group in Newport Beach, Calif., signals that the supplement company adheres to good manufacturing practices (GMPs). A company with GMPs tests its raw materials to confirm what they are, keeps careful records so all ingredients and products can be tracked, and maintains certain standards of cleanliness at its plant. For a list of the companies NNFA has certified, visit www.nnfa.org or call 800-966-6632.

NSF International: A mark from NSF International, a nonprofit certification organization in Ann Arbor, Mich., confirms that the supplement maker follows GMPs. But the seal also means that NSF International tested the product and found that it contains what it should and disintegrates properly. To search a database of the products NSF International has certified, visit www.nsf.org.

USP: The mark from the United States Pharmacopeia (USP), a nonprofit, nongovernment organization in Rockville, Md., means the supplement company follows GMPs. It also signals that the USP has run tests on the product and confirmed that it contains what the label says it should. To find out which products it has certified, visit www.usp-dsvp.org.

Consumer Lab: This testing company in White Plains, N.Y., checks supplements to confirm their ingredients and ensure that they disintegrate properly. A seal from Consumer Lab does not mean that the supplement maker follows GMPs. Unlike the other programs, this one is not necessarily voluntary. Consumer Lab usually tests products because they're widely available. But some companies do volunteer to have their products tested. You can visit www.consumerlab.com and pay a small fee to read its findings.

If the brands at your store don't carry any of these marks, pick a brand and call the company that makes it, Domp says. Ask to speak to someone in the technical department, and inquire if the company follows GMPs. If it does, ask if the company has been independently audited to confirm it's sticking to them.

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