Vitamins: Separating Fact From Fiction
Experts cut through the hype about the health benefits of vitamin supplements.
Calcium and Vitamin D
Calcium supplements are also important for certain age groups, Bailey says. The Institute of Medicine, part of the National Academy of Sciences, recommends that adolescents get 1,300 milligrams of calcium a day. One cup of milk or calcium-fortified orange juice contains about 300 milligrams of calcium.
Other sources of calcium include cheese, tofu, yogurt, vegetables, and beans. A typical calcium supplement may contain 500 milligrams or 600 milligrams of calcium. Bailey gives her 15-year-old son a daily calcium supplement at dinnertime. People over 50 should get 1,200 milligrams a day of calcium to ward off osteoporosis (thinning of the bones), Bailey says.
Federal dietary guidelines recommend that the elderly, the homebound, and people with dark skin boost their vitamin D intake with both fortified foods and supplements to reduce the risk of bone loss. Vitamin D helps with absorption of calcium; often calcium supplements will also contain vitamin D. (The full federal guidelines, updated in 2005, are available at www.health.gov/dietaryguidelines.)
Special groups such as smokers, pregnant women, or people recovering from traumatic injury may need additional supplements, Cross says. Decisions to take supplements beyond a multivitamin are best made with your doctor or registered dietitian, she says.
The evidence is strong that a healthy diet can ward off chronic diseases like cancer and heart disease. What's less clear is if big intakes of particular micronutrients can boost that preventive effect further.
There is promising evidence that the mineral selenium could prevent a variety of cancers, says Alan Kristal, DrPh, associate chief of cancer prevention at the Fred Hutchinson Cancer Research Center in Seattle. But beyond selenium, the data aren't promising, Kristal says. For example, there's no solid evidence that taking large doses of antioxidants like vitamins B or C have any beneficial effect.
Controversial Health Claims
As you seek the proper multivitamin or dietary supplement, it's best to keep your guard up. The supplement industry is relatively unregulated, and you can injure or even kill yourself with "natural" products bought at your neighborhood supplement store.