There’s still plenty of controversy. But new findings are providing clearer answers -- and better advice on how to spend your hard-earned health dollars.
Many experts say most people should skip pills and concentrate on healthier diets.
“There are hundreds of compounds in fruits, vegetables, whole grains, and other foods from plants that work synergistically in ways we haven’t even begun to understand,” says David Rakel, MD, director of integrative medicine at the University of Wisconsin. “You can’t take one or two, put them in a pill, and expect to get the same benefits. A diet based on foods from plants offers the best defense against many chronic diseases.”
But many people don't always eat healthfully. Would a multivitamin help?
Multivitamins: Are They Worth It?
“We know there are documented nutritional gaps in Americans’ diets, including vitamins C, D, E, calcium, and magnesium, among others,” says Andrew Shao, PhD, senior vice president of scientific and regulatory affairs for the Council for Responsible Nutrition, a supplements industry trade group. Filling those gaps with a multivitamin makes sense, Shao says.
Whether or not multivitamins prevent disease is another matter.
In 2006, a panel of experts convened by the National Institutes of Health concluded that there wasn’t enough good data to say whether multivitamins help prevent disease.
One of the latest and largest studies, published in 2009, tracked for five years the health of about 77,700 people aged 50-70, comparing those who took supplements with those who didn’t.
“Taking a multivitamin had no effect at all" on participants' death rate during the study, says epidemiologist Emily White, PhD, of Seattle's Fred Hutchinson Cancer Research Center.
"There was a hint that people who ate relatively poor diets did get some benefit from taking multivitamins," says White. But that benefit was small and could have been due to chance.
"If there’s any message in this, I think it’s that people should eat a healthy diet and not rely on multivitamins,” White says.
Some researchers worry that multivitamins may pose risks. A 2010 Swedish study of some 35,000 women showed a higher risk of breast cancer among those who took a multivitamin.
Antioxidants for Women
What about zeroing in on specific nutrients? Over the years, several become supplement superstars.
But recent research has dimmed the enthusiasm for antioxidant vitamins such as C, E, and beta carotene. Research shows there’s almost no benefit to taking them in pill form -- and maybe some risks.
A 2007 analysis of 68 different studies, for example, published in the Journal of the American Medical Association, linked vitamin E, vitamin A, and beta carotene supplements to a higher death rate in some groups. And high doses of vitamin C supplements have been linked to greater risk of developing cataracts, according to 2010 findings from a study of more than 24,000 Swedish women.
However, those studies don't prove that vitamins were responsible for the results.
“No antioxidant supplements have been shown to prevent cancer, especially in well-nourished populations. And there may be some risks,” says Marji McCullough, ScD, RD, strategic director of nutritional epidemiology at the American Cancer Society. “So the best advice is to eat a variety of fruits and vegetables, which are rich in antioxidants, and not depend on pills.”
Calcium for Women
Calcium is essential to strong bones throughout life. The Institute of Medicine (IOM) recommends that:
- children aged 1-3 get 700 mg of calcium per day
- children 4-8 get 1,000 mg per day
- adolescents aged 9-18 get 1,300 mg per day
- adults 19-50 get 1,000 mg per day
- women over age 51 get 1,200 mg per day
For most people, pills aren’t the best way to get enough calcium, according to Robert Heaney, MD, a Creighton University professor of medicine and an expert on calcium and vitamin D. “The body needs both calcium and protein for bone health,” Heaney tells WebMD. “So the ideal source of calcium is dairy products, not supplements.”
Here are the calcium levels of some foods:
- 8 ounces of yogurt: 415 mg of calcium
- 8 ounces of milk: 300 mg
- 3 ounces of salmon:181 mg
Many foods, including orange juice, are fortified with extra calcium. Tofu and leafy greens are good plant-based sources of calcium.
But not everyone can tolerate dairy, nor eat enough other calcium-rich foods to meet recommendations. The IOM's recommendations still support taking calcium supplements, and there are many studies that show benefit.
Calcium carbonate tablets cost the least. Take them at meals; stomach acid aids digestion. Calcium citrate may be slightly more effective for people with low stomach acid, such as the elderly.
Adequate calcium may help prevent high blood pressure. Here, too, food sources appear to be better than pills.
When Harvard School of Public Health researchers studied nearly 29,000 middle-aged and older women, they found that women who ate more low-fat dairy products were less likely to have high blood pressure. Taking calcium and vitamin D supplements, in contrast, had no effect on blood pressure. But that study doesn't prove cause and effect, so it's not clear that dairy products made high blood pressure less likely.
Vitamin D for Women
The latest superstar supplement is vitamin D. There's growing evidence for its importance to good health.
Supplements seem to help. A 2010 report, published in the Annals of Internal Medicine, showed a small but consistently lower risk of heart disease in people who took up to 1,000 international units (IU) of vitamin D.
The IOM recommends 600 IU of vitamin D per day for people ages 1-70 and 800 IU for those over 70.
“If you measure blood levels of vitamin D in people who work outside during the summer, they typically reach 60 to 80,” Heaney says. “So that may represent the number that the body evolved to maintain.”
The most natural way to boost vitamin D levels is through exposure to sunlight, which triggers the skin to make vitamin D. Some doctors encourage some patients to spend a little time in the sun, without sunscreen, to make vitamin D.
“Obviously, it’s very important not to get sunburned,” Rakel says. “But a moderate amount of sun exposure can have important health benefits.”
Experts still recommend putting sunscreen on your face at all times, since the face is at high risk for skin cancer. Sunning yourself to raise vitamin D levels is less effective for people with dark skin, and less effective for everyone as they age.
If you work indoors, avoid the sun, or live in northern latitudes where ultraviolet levels are low, consider a vitamin D supplement. Talk to your doctor about the best dose. Choose supplements that contain D3, the vitamin's most easily absorbed form.
Folic Acid and Choline
For women of childbearing age, getting enough folic acid and choline is crucial.
Folic acid, a B vitamin, is essential for building new cells. Falling short during pregnancy has been linked to increased risk of major birth defects of a baby’s brain and spine. Women of childbearing age need 400 micrograms of folic acid every day. There are two simple ways to make sure you get enough.
- Take a multivitamin that contains 400 micrograms.
- Eat a breakfast cereal fortified with 100 percent of the daily value (DV) for folic acid.
Adequate choline levels during pregnancy also help prevent birth defects. This essential nutrient plays a role in blood vessel growth in the brain. Surveys suggest that less than 15% of pregnant women get enough. Experts recommend that pregnant women get 450 mg a day, or 550 mg a day if they are lactating.
Although some multivitamins contain choline, many foods are rich in this essential nutrient. Leading dietary sources include eggs, liver, chicken, beef, pork, milk, and a variety of vegetables and grains.