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10 Multivitamin Myths Busted

We cut through the misinformation surrounding this dietary supplement staple.

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The multivitamin is the most popular type of supplement, most often taken for overall health and wellness. Nevertheless, myths about multivitamins persist and can reduce the effectiveness of these foundational supplements—or even discourage you from taking them. Here are the facts.

10 Myths About Multivitamins:

1. A healthy diet will provide all the essential nutrients.

While a perfect diet could theoretically provide adequate nutrients, it rarely exists in the real world. In fact, large U.S. government surveys show that deficiencies are much more common among people who take no supplements.

A study of more than 10,000 American adults, published in The Journal of Family Practice, compared nutritional shortfalls among people who took no supplements and those who took a multivitamin on most days. Among the differences, those who took no supplements were:

  • 24 times more likely to lack vitamin D
  • 8 times more likely to lack vitamin E
  • At least twice as likely to lack vitamins A, C, and K, and magnesium

Vitamin D is essential for bone health. Vitamin E protects against DNA damage. Vitamins A, C, and K are necessary for healthy vision, immunity, and heart health. And magnesium is a key component of more than 300 internal functions in the human body.

Another large study of American adults found that those who took multivitamins at least 21 days per month had virtually no deficiencies in 14 of 17 essential nutrients examined. The three exceptions were vitamin D, calcium, and magnesium—multivitamins aren’t designed to provide the full daily requirements of these nutrients. In contrast, there were significant deficiencies in about a dozen of the nutrients tested among people who took no supplements.

2. You only need to take a multivitamin if your energy sags or you feel under the weather.

Quite the contrary. Studies show that taking a multivitamin every day—or at least on most days—provides the most benefit. Yet, when researchers asked more than 5,000 multivitamin users how often they took the supplements, only one in five took their multis at least 21 days each month.

3. If you miss a day, you should double the dose the next day.

The human body does not store most B vitamins (B12 is an exception), vitamin C, and zinc, yet it needs them every day. If a double dose contains more than you can absorb, the excess will be excreted, so it doesn’t compensate. Other vitamins and minerals can be stored, but it makes more sense to take them daily.

4. It doesn’t matter if you take a multivitamin with or without food.

Nutrients that are water-soluble, such as B vitamins and vitamin C, are absorbed without food. But fat-soluble ones, such as vitamins A, D, E, and K, need to be taken with some fatty food to be properly absorbed. Since a multivitamin contains both types, always take it with food that contains some fat. In addition, when taken on an empty stomach, supplements can produce digestive discomfort.

5. It’s especially important to start taking a multivitamin if you get pregnant.

While this is true, it’s a myth that you can wait until after discovering that you’re pregnant. Lack of folic acid can lead to neural tube defects, in the brain and spine, which develop in the first month of pregnancy—before many women even know that they’re pregnant.

Any woman of child-bearing age should get 400 mg of folic acid daily—an amount found in many multivitamins—to reduce the risk of neural tube defects if she were to conceive. During pregnancy, 600 mg daily is recommended to support healthy growth of a baby.

6. You shouldn’t take a multi if you take prescription drugs.

There are many scary warnings about combining supplements and drugs. However, the National Center for Complementary and Integrative Health, one of the National Institutes of Health, has concluded that multivitamins containing no more than 100 percent of the Daily Value of vitamins and minerals typically do not cause a problem with medications, with one exception.

If you take warfarin (Coumadin or Jantoven) to thin blood, vitamin K will decrease its effectiveness. Your doctor can adjust the dose of the drug to compensate, or you can take a multivitamin without vitamin K. Other blood thinners may not react this way, but to be sure, check with your doctor before taking vitamin K in a multivitamin or other supplement if you take blood thinners.

7. If you take a multivitamin every day, it doesn’t matter what you eat.

Supplements, by definition, are meant to supplement nutritious food rather than replace it. If your diet consists of junk food, supplements can help, but you’re fighting an uphill battle. Foods contain many more nutrients than anyone could pack into pills.

8. If your urine turns yellow or orange, something is wrong.

Vitamin B12 (riboflavin) turns your urine yellow or orange when you excrete amounts your body can’t use. It’s quite normal and nothing to worry about. If you don’t like the color, drink more water.

9. All multivitamins are basically the same.

The number of nutrients in a multivitamin can vary from a few to more than two dozen. Although products with few ingredients can be beneficial, they don’t provide as much nutritional insurance. For example, only 10 percent of American adults get enough choline, which is essential for the brain and nervous system, but only some multivitamins include it.

In addition, some products are formulated for women or men at different stages of life, as requirements vary. In the case of iron, which can be toxic in high doses, premenopausal women require 18 mg daily, but women after menopause, as well as men of all ages, require only 8 mg.

10. It doesn’t matter if your multivitamins are old.

Multivitamin products have expiration dates for good reason: Their potency will eventually decline. If you’ve had a product for a long time, check the date. If it’s expired, get a new one. Store supplements away from moisture and heat, not near a stove or microwave, not on top of the fridge, and not in a bathroom cabinet. A cool kitchen cupboard or drawer is a good storage option.

Healthy Tip!

For more information about the importance of multivitamins: The Surprising Health Benefits of Multivitamins.

Daily Values: What They Mean

Daily recommended amounts, which are estimated to be adequate for most men or women at a certain age, have been established for many basic nutrients.

Daily recommended amounts, which are estimated to be adequate for most men or women at a certain age, have been established for many basic nutrients. Daily Values, usually listed in Supplement Facts on labels as “%DV,” are not recommendations but are designed to be a guide for comparing products.

How Daily Value Is Calculated

The Daily Value is based on the highest recommended amount of a nutrient. For example, women need 700 mcg of vitamin A, while men need 900 mcg. The Daily Value of vitamin A is 900 mcg—the higher amount. If %DV is 100, the product contains 900 mcg of the vitamin, and if %DV is 50, it contains 450 mg.

Individual Needs

Daily Values don’t take individual needs into account. Vegans and older people, for example, are likely to need extra B12 in addition to a multivitamin. Women who are pregnant or breastfeeding should take a multi designed for those situations. Some products also include herbs or other natural ingredients for specific benefits, such as joint health or easing menopause or stress. For optimum benefits, it makes sense to choose a product designed for your specific needs.