"In my opinion, everyone should take a daily multivitamin supplement with minerals, because our food supply lacks sufficient nutrients," says Dr. Gerald Mullin, director of integrative nutrition services at Johns Hopkins Hospital in Baltimore. But there are few places as confusing as a supplement aisle. We've consulted experts who helped us develop a guide to choosing the right ones for you. All amounts are for adult women, unless noted. If you're pregnant or breastfeeding, ask your doctor for revised amounts. Read on for their advice.
What it Does: Prevents night blindness; enhances immunity by stimulating the production and activity of white blood cells; regulates cell growth and division.
How Much You Need: 2,300 International Units (IU)/day
Supplemental Information: Vitamin A is available in two forms. The first is the "preformed" kind called retinol, which is found in animal products such as liver and whole milk. Preformed A can be toxic at levels above 10,000 IU. The second is natural beta-carotene, from fruits and veggies, which your body uses to form its own vitamin A, and is much safer. Check labels and choose a supplement that has all or most of its vitamin A as beta-carotene.
What it Does: Enables normal nerve cell communication. Research is underway to determine whether vitamin B6, along with B12 and folic acid, can combat heart disease by reducing levels of homocysteine, an amino acid shown to increase stroke and heart attack risk.
How Much You Need: Ages 19 to 50: 1.3 milligrams (mg)/day; Ages 51 and up: 1.7mg/day
Supplemental Information: Do not exceed 100 mg a day of vitamin B6; high levels are associated with nerve damage.
What it Does: Helps maintain healthy nerve cells and red blood cells, and is essential to making DNA. People over 50 often have trouble absorbing enough vitamin B12 from food sources, so experts advise taking a multivitamin that contains B12.
How Much You Need: 2.4 micrograms (ug)/day
Supplemental Information: There's no upper limit for vitamin B12 because no adverse effects are associated with taking high doses.
What it Does: Helps produce and maintain new cells and prevents changes to DNA that could lead to cancer. Both adults and children need folate to make normal red blood cells and prevent anemia. Folate, one of the B vitamins, occurs naturally in food; its synthetic form is folic acid.
How Much You Need: 400 ug/day
Supplemental Information: Because it's difficult to get enough folate from food, the government now mandates the addition of folic acid to flour, cornmeal, pastas, rice, and other grain products.
What it Does: Helps make collagen, the tissue needed to build and maintain bones, teeth, gums, and blood vessels.
How Much You Need: 250 to 500 mg/day
Supplemental Information: Most multivitamins don't have enough C, so buy additional tablets. All C tablets are digested in a similar fashion, so there's no point in buying expensive brands. If regular vitamin C upsets your stomach, try the less acidic Ester-C form, suggests Dr. Mark Moyad, director of preventative and alternative medicine at the University of Michigan Medical Center.
What it Does: Maintains bone health and density by allowing the body to absorb and retain calcium and phosphorus. It may also lower risk for several cancers, and for respiratory infections.
How Much You Need: A minimum of 1,000 IU/day
Supplemental Information: Sunshine helps your body form vitamin D, but people with dark skin, those who wear sunscreen (as you should), or live in northern areas (roughly above the line that connects Atlanta to Los Angeles) may not absorb enough sunlight, especially in winter.
What it Does: This powerful antioxidant protects your cells against free radicals that contribute to the development of heart disease and cancer. Vitamin E also enhances immune function and is a factor in DNA repair.
How Much You Need: A minimum of 22.5 IU/day and a maximum of 1,500 IU/day
Supplemental Information: "Some 96 percent of women don't get enough vitamin E from their diets," says Maret G. Traber, professor at the Linus Pauling Institute at Oregon State University. Listed amounts are for the natural form of vitamin E, d-alpha-tocopherol, the kind experts recommend. (Look on the bottle's ingredient list; it may not say on the box.)
What it Does: Calcium helps build and strengthen bones and teeth. It's also vital for muscle contraction, blood vessel contraction and expansion, hormone and enzyme secretion, and for sending messages through the nervous system. If you don't eat calcium-rich foods such as dairy products, or dark leafy greens, and if you don't take calcium supplements, your body will compensate by taking what it needs from your bones.
How Much You Need: Ages 9-18: 1,300 mg/day; Ages 19-50: 1,000 mg/day; Ages 51 and up: 1,200 mg/day
Supplemental Information: Multivitamins typically don't contain all the calcium you need. So take a separate calcium supplement at the same time you take a multivitamin. There are multiple forms of calcium; ask your pharmacist for help choosing among them.
What it Does: Helps maintain normal muscle and nerve function, steadies heart rhythm, supports a healthy immune system, and keeps bones strong. May help people manage chronic conditions such as hypertension, anxiety, diabetes, and heart disease.
How Much You Need: 310 to 320 mg/day
Supplemental Information: Magnesium comes in many forms, including manganese, magnesium oxide, and magnesium citrate. Ask a pharmacist to help you decide which form is best for you.