Q. How can I choose the best multivitamin for general health?

A. Use these four tips to pick the multivitamin or mineral supplement that’s right for you:

1. 
   
2. Look for a USP dietary supplement verified mark on the product label, which indicates the multivitamin meets quality standards set by the United States Pharmacopeia. The USP mark means the supplement has passed tests to ensure that it contains the ingredients listed on the label, in the amounts listed, and that the ingredients will dissolve in your stomach in a reasonable amount of time. It also means the multivitamin was manufactured using safe and sanitary procedures and does not contain harmful contaminants. (It does not guarantee, however, that the nutrients will be absorbed.)
3. Women of childbearing age need to consume 400–800 mcg of folate daily from a supplement or from fortified foods (in addition to what you obtain from eating a varied diet)—before conceiving—to greatly reduce the risk of having a baby born with a neural-tube birth defect.
4. Premenopausal women should select a multivitamin supplement that provides 18 mg of iron. Too much iron, however, can build up in the body’s organs and become toxic. Generally, men should look for a supplement without iron, while postmenopausal women should select one that is either iron-free or contains no more than 8 mg.
5. No multivitamin contains the Recommended Dietary Allowance (RDA) for calcium (1,000–1,200 mg per day for adults ages 19 to 70-plus). If you don’t get the RDA for calcium from your diet or multivitamin, plan to take an extra calcium supplement to make up the difference.

This Ask the Expert is written by Suzanne Girard Eberle, a registered dietitian, speaker, and freelance writer in Portland, Oregon.