How to Pick a Multivitamin – and Why You Might Not Really Need to Take One

Is there a difference between generic and brand name? Do you even really need to take one at all? We've got answers.

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Wondering how to pick a multivitamin that will fill in what you need? A lot comes down to what you are and aren’t getting from your diet.

“There’s been some evidence that people whose diets include high amounts of vitamins E and C, beta-carotene and possibly lycopene are less prone to heart disease and cancer. But two large research reviews, published in 2002 and 2003, found that there really isn’t a well-substantiated argument for—or against—a general multivitamin. It might help lower the risk of heart disease and cancer, or it might not matter at all,” says Karen Collins, MS, RD, CDN, a nutritionist with the American Institute for Cancer Research. “Essentially, the researchers concluded that people who want to take multivitamins should not be discouraged from doing so, but unless there’s a particular reason to believe they are lacking in one or more nutrients, they shouldn’t be strongly persuaded to take them either.”

And if it’s mainly calcium you’re lacking, Collins says a separate calcium supplement is better than a multivitamin, because most multis can cram in only a scant 200 milligrams (mg) of calcium (it’s a bigmineral)—and depending on age and other factors, you need 1,200–1,800 mg a day.

In general, though, it’s not a good idea to boost individual nutrients unless lab tests show that your body levels are low. “Nutrients work interdependently and synergistically. When one is increased significantly, it can throw off the balance and create ‘deficiencies’ of other nutrients. For example, loading up with zinc can create a copper deficiency.”

Others who might be interested in multivitamins are people looking to beat heart disease. But there aren’t any magic pills: The American Heart Association emphasizes that eating foods rich in antioxidants (fruits, vegetables, whole grains, beans) is the key to better health.

How do I know if I should take a multivitamin?

It depends on your eating habits. Because so many products—cereals, juices, yogurt smoothies, protein bars—are fortified with vitamins and minerals, you can end up eating the equivalent of a multivitamin without knowing it. But for many of us, junk food cravings, creeping-up age or ongoing health problems starve our bodies of the nutrients they need to function. So, there’s no single answer, says Collins.

Do vegetarians and vegans in particular need to take a multi?

Again, it depends on eating habits. But vegetarians in general and vegans, in particular, do run the risk of a fistful of deficiencies, including:

  • Iron. It transports oxygen in red blood cells to other cells, including muscles. But fortified cereals may already supply a day’s worth, so check before adding more. Other sources include whole grains, vegetables and beans.
  • Magnesium. Without this mineral, the body can’t metabolize calcium. It also aids in clotting blood, absorbing minerals and generating body heat. The best vegetarian sources are whole grains, leafy greens, legumes, soy and nuts.
  • Selenium. A powerful antioxidant, it protects against cancer (notably prostate cancer) and other serious health problems. Grains are vegetarians’ major source of selenium, but others include garlic, onions, broccoli and mushrooms.
  • Calcium. This multifunctional mineral strengthens bones, clots blood, regulates the heart, helps the body use iron and wards off PMS. Obvious calcium sources are dairy products—milk, cheeses, yogurt—but getting enough calcium can be a problem for vegans. They can find ample calcium in certain dark green vegetables, soybeans, almonds, fortified soy milk, tempeh or tofu.
  • Vitamin D. This essential vitamin enhances the absorption of calcium, which helps fight bone loss. Vegans are especially vulnerable to not getting enough D. Fifteen minutes of sun exposure a day to the face and hands is often sufficient to get the D you need. But if the weather’s dreary and if fortified soy milk and cereal aren’t available, you can get D through a multi.
  • Zinc. It fights infections and helps the body digest protein, produce energy and absorb vitamin A. Ironically, vegetarian males who consume otherwise healthful amounts of whole grains—which contain phytates, which bind zinc—could be at risk for low zinc intakes. Low zinc levels have been linked to low sperm counts, says Bruce Ames, PhD, a professor of molecular cell biology at the University of California, Berkeley.
  • Vitamin b12. It fights Alzheimer’s disease and multiple sclerosis, prevents anemia, promotes growth, maintains a healthy nervous system and reduces fatigue. Sources of vitamin B12 include nutritional yeast, cows’ milk, fortified soy milk, yogurt, eggs, fortified cereals and fortified meat substitutes such as veggie burgers. Because B12 is found in animal products, vegans probably don’t get enough of the vitamin; a multi will help.

How can I pick the right multi, considering my age, gender, etc?

Be realistic about your diet. For instance, do you really need to increase your calcium intake?

If you eat a lot of dairy—milk, yogurt, cheese, ice cream—you don’t need a multi with 100% DV (percent of daily value) for calcium. Sometimes the phrase “less is more” applies. Bottom line: Don’t get panicky about not getting 100 percent of your RDA in a supplement. Collins adds, “Even if your diet isn’t meeting all your needs, it certainly isn’t providing zero!” Avoid the “if some is good, more is better” mentality.

“It doesn’t apply to micro-nutrients,” Ames says. Too much iron, zinc, copper, beta-carotene and some vitamins, such as A, is toxic. You can check each nutrient’s Tolerable Upper Intake Levels (UL) at They’re set by the same panel that sets the RDAs. Pay careful attention to the UL for iron (45 micrograms), zinc (40 mg), copper (10 mg), selenium (400 mg) and chromium (1,000 mg). Overdoing these can cause everything from gastrointestinal and menstrual problems to anemia and a depressed immune system. Pregnant women should only take supplements under the advice of their health care practitioner.

Related: Are You Getting Enough Vitamin C

What should I be looking for to know how to pick a multivitamin?

Look for logos from and/or US Pharmacopeia (USP) to show that the multi has been tested for quality, strength, purity and good manufacturing practices. is an independent, private organization that analyzes supplements to test that they actually contain what the label says in the amount listed. They also test for purity (lack of contaminants such as lead) and bioavailability (breakdown of the supplement to forms that the body can absorb).

For the cost of a membership to the ConsumerLab site, you can check which supplements pass and fail these criteria. The USP helps to ensure that consumers receive quality medicines by establishing standards that pharmaceutical manufacturers must meet. Visit for more details.

What’s the significance of the expiration date?

It tells you when the supplement starts losing its potency. Check it carefully so that you get what you pay for.

What should I ignore on a label?

Don’t choose a multivitamin for added extras, such as herbs. If you want to take these, you’re better off getting them separately (there’s a limited amount of stuff that can be packed into one multi). Just because a multivitamin contains one or more of these ingredients doesn’t mean the quantities are significant enough to have any effect. Also ignore marketing eye-catchers such as “stress formula,” “high potency” and “maximum” when deciding how to pick a multivitamin. “‘Stress formula’ doesn’t mean it will help you deal with stress. Same thing for ‘energy’ phrases—extra vitamins don’t give you energy. ‘High potency’ and ‘maximum’—the latter has no legally defined meaning, by the way—also have little or no significance,” Collins says.

What’s the difference between generic and brand-name multis?

Almost nothing, according to our experts—except the price. All the same tips about how to pick a multivitamin apply equally, regardless of manufacturer.

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