What the best multivitamin has
- Verified ingredients. It's not unusual for a product to have too much or too little of the ingredients stated on the label. There are a few organizations that test for accuracy in labeling and ingredients; try to find a multivitamin that has been tested by a reputable, independent organization such as ConsumerLab.com or LabDoor.com.
- 100 percent of the daily value (DV) of most of the essential vitamins and minerals. Don't take a multivitamin with excessively high levels of essential vitamins and minerals; at best, you'll just expel the excess through urine. At worst, you could suffer health complications.
- The correct amounts of folic acid for females. Folic acid (synthetic folate), or folate (when from food sources), can help prevent neural tube defects that develop before most women know they're pregnant. Experts advise all women of childbearing age to take 400 mcg DFE daily of folic acid supplements. Once pregnant, women should bump up their intake to 600 mcg per day, while breastfeeding women should get 500 mcg per day. However, the supplements on the market at the time this report was prepared may exceed those daily requirements due to new guidelines from the FDA. See the introduction to our section on the Best Prenatal Vitamins for a detailed discussion of these changes.
- A reasonable amount of vitamin A. Vitamin A is increasingly included in other fortified foods, making it easy to reach the recommended daily upper limit. Even small excesses of vitamin A can cause health problems. Look for a maximum of 5,000 IU, although experts in men's health recommend no more than 2,500 IU in a multivitamin. At least half of the vitamin A should be in the form of beta-carotene, a safer form than fat-soluble retinol.
Know before you go
Talk to your doctor first. Multivitamins can interfere with prescription medications. Consult your physician before starting a new multivitamin regimen.
Consider a basic multivitamin. Companies charge extra for formulas touting heart health, energy and weight loss, yet many of those claims are untested and these products might not be worth the extra cost.
Buy generic. Experts say store brands are just as effective as their pricier counterparts. Many generic multivitamins such as Walmart's Equate, Costco's Kirkland Signature and Target's up&up have been tested and found to contain the nutrients listed on the label and dissolve properly.
You may need to boost your vitamin D and calcium consumption. Recommendations for these two nutrients have been increased. If your current multivitamin is low, consider switching or asking your doctor about additional supplementation.
Compare similar products. Chewable, gummy and liquid multivitamins may not contain the same amount of nutrients that their pill-form counterparts do. Compare labels before you buy.
Check the expiration date. Expiration dates are voluntary, but nearly all supplement manufacturers list them on the packaging.
Shop carefully if you're a vegetarian/vegan. Many store-brand and mainstream brands include fish oils or gelatin that's derived from pork or beef; vitamin D3 is often derived from lanolin, a no-no for vegans. Look specifically for brands labeled as suitable for vegans or vegetarians; if a product isn't clearly marked, assume that it's not suitable for strict vegetarian or vegan diets.
Understanding the alphabet soup of RDA, DV, DRI and UL
Multivitamin ingredients are measured in terms of the daily value (DV). The recommended amount of each vitamin and mineral is established by the FDA and is based in part on the recommended dietary allowances (RDA). To add to the confusion, RDA and DV are used concurrently to describe nutrient recommendations. According to the National Institutes of Health, the RDA is the amount of a nutrient needed to meet the daily basic needs of healthy people. It's one of the factors used to determine daily values, the amounts recommended to help prevent disease that are often higher than the RDA. The DV is presented on food labels and the RDA is mainly used by health professionals.
The newest standard for nutrient requirements is Dietary Reference Intake (DRI). This system was developed by the U.S. National Academy of Sciences' Institute of Medicine in consultation with Health Canada and is used in both countries. DRI recommendations are made up of three components: the estimated average requirements (EAR), a level nutritionists say should meet the needs of 50 percent of the people in a defined age and gender group; the RDA or, where no RDA has been established, the adequate intake (AI); and the Tolerable Upper Intake Level (UL), meaning the highest level that experts consider safe.
Confused? You're not alone. Even among research and nutrition professionals, there's considerable debate about optimal levels and safe upper limits. Part of the problem is that researchers don't yet understand completely how these substances work in the body.
For every study that links a supplement to a supposed health benefit, there's probably another study that links it to adverse health effects. So what's a person to do? Experts agree that getting your nutrients from whole foods is best -- you reap all the benefits of each individual vitamin without the risk of side effects seen when those same vitamins are taken in supplement form. The science on nutritional supplements is constantly evolving, but it's unlikely that a single dietary supplement or vitamin will ever be a silver bullet for our health woes. Your best bet is to ask your doctor whether specific supplements or multivitamins are necessary for your individual health condition.