The Good and Bad of Vitamins Many take them daily—but do they all really help?

The Good and Bad of Vitamins Many take them daily—but do they all really help?. Americans shell out $23 billion every year on multivitamins and other dietary supplements. But is it money well spent?

Over the past year, a number of studies have looked at vitamin use and failed to find any significant health benefits. In November 2008, results from the Physicians’ Health Study II, a clinical trial of nearly 15,000 male doctors, revealed that taking vitamin C or E supplements did not lower the risk of cancer or cardiovascular disease.

The following month, the Journal of the American Medical Association reported that researchers who studied more than 35,000 men said that high doses of vitamin E and selenium, taken for an average of five and a half years, did not appear to prevent prostate cancer.

And in the largest and most recent study—the Women’s Health Initiative (WHI), which followed more than 160,000 postmenopausal women for eight years—researchers found that multivitamins did not reduce women’s risk of cancer or cardiovascular disease or make them live longer than women who did not take supplements.

So, is it time to throw those vitamin bottles in the trash? Not so fast, doctors say.

More studies are needed

One limitation of these trials is the age of the participants. In all three studies, the average age of the subjects was close to 60. “It’s possible that the window of opportunity for multivitamins is earlier in life,” explains Dr. JoAnn Manson, one of WHI’s principal investigators and chief of preventive medicine at Boston’s Brigham and Women’s Hospital. It could be that you need to take the supplements in your 20s, 30s, or 40s to reap the potential benefits.

In addition, previous studies suggest that you may need to take vitamins for many years before you experience the benefits, according to Dr. Manson. American Cancer Society researchers reported in 2003 that men and women who took multivitamins for more than a decade had a lower risk of colon cancer.

In the WHI study, the women chose to take multivitamins rather than being randomly assigned to take either a vitamin pill or a placebo. This is a key distinction, says WHI study lead author Dr. Marian L. Neuhouser, since “the people who take vitamins may be the least likely to need them, because they already have a good diet and tend to be generally healthy.”

A healthy diet is best

Regardless of what the studies show, doctors still caution that popping a pill is not a substitute for eating a healthy, balanced diet. “It’s much better to get your nutrients from foods and use supplements if needed or as a form of insurance,” Dr. Manson says. “There are hundreds of compounds in plant foods that are important, and a multivitamin might only have 20 to 25 of those compounds,” adds Dr. Neuhouser, a researcher at the Fred Hutchinson Cancer Research Center in Seattle.

When to take supplements

While the jury is out for the general population, some people do need multivitamins:

• Pregnant women should take a vitamin with adequate folic acid to help prevent birth defects.
• Men and women 50 or older need 1,200 mg of calcium a day and extra vitamin D, which can be hard to get from food alone.
• Adults with a poorly balanced diet are advised to take a multivitamin, says Connie M. Weaver, a professor of Foods and Nutrition at Purdue University. Plus, if you are cutting calories, taking a multivitamin ensures that you will meet your nutritional needs. ( msn.com )
  

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