Vitamins: Separating Fact From Fiction
Experts cut through the hype about the health benefits of vitamin supplements.
"There are literally thousands of these compounds, and we're just
scratching the surface on knowing what their role is," says David Grotto, a
registered dietitian and spokesman for the American Dietetic Association.
"We're sending the wrong message if people believe they've got everything
under control and if they're taking vitamins while eating a horrible
Choosing a Supplement
It's easy to become overwhelmed when looking at the dietary supplement
shelves of a health food store or even your local supermarket. While many of
the health claims are unproven or downright bogus, some supplements may be
useful for some groups.
Major multivitamin makers typically produce different varieties for men,
women, children and older folks. Picking a pill that fits your group makes
sense, says dietitian Grotto, as the optimal level of various nutrients varies
by age and sex. For example, premenopausal women need more iron than children
or the elderly, he says.
But the elderly have a harder time obtaining adequate amounts of vitamin
B-12 from natural sources, so the need for supplementation may increase with
age, says Lynn Bailey, a University of Florida nutritionist who teaches courses
Folate, or folic acid, is key to preventing birth defects (such as spina
bifida), Bailey says. Bailey says all women of childbearing age should ensure
they get 100% of the RDA of folic acid through fortified food or a
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
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.