Health, in one simple pill. That’s the perceived promise behind multivitamins and dietary supplements. Millions of Americans dutifully take their dose every day, believing it will ward off a cold (it won’t) or prevent cancer (it definitely won’t), or simply make us more healthy (only some of us).

For many, supplements also serve as nutrition insurance, covering a multitude of food sins -- a candy bar for lunch, drive-thru for dinner. But research is showing that this shortcut to “perfect nutrition” may be giving short shrift to your health, occasionally even doing more harm than good.

Message: Not in a Bottle

“Contrary to common perception, there’s actually little evidence that healthy individuals will gain health-promoting benefits from taking a multivitamin,” says Duke nutrition scientist Connie Bales, PhD, RD.

There’s no research to support that they prevent cancer or other chronic diseases, and they cannot effectively replace a well-balanced meal, according to Duke researcher Denise Snyder, MS, RD, CSO, LDN. “Most vitamins and minerals that people need can be obtained by making better food choices -- a diet that includes a variety of healthful foods in lots of colors on your plate.”

Research even suggests that vitamins and minerals are more effective when in food form -- in other words, taking the carrot out of your beta-carotene may actually make it less helpful to your body.

Approved for Some Audiences

Of course, there are always exceptions. “If your eating habits are severely compromised -- for example, due to severe food allergies, pronounced loss of appetite, or if your body is unable to absorb nutrients normally -- supplements can help to fill a gap,” says Bales. Reaching certain life milestones -- pregnancy, menopause, and the big 5-0 -- also justifies the need for specific supplements.

“Your body requires more vitamins and minerals [think calcium and vitamin D], while at the same time, the likelihood increases that you’re not getting enough,” she says. Strict vegetarians, people prone to osteoporosis, and the elderly should also discuss supplements with their doctor.

Side Effects May Include...

Supplements are neither tested nor approved by the Food and Drug Administration before hitting the shelves. Most people underestimate supplements and their potent effects, neglecting to inform doctors of their medicine cabinets’ complete contents.

“Supplements with very high levels of various nutrients can have serious consequences if they counteract any drug or medical therapy,” says Bales. “Especially when combined with other supplements or highly fortified foods, these products can lead to toxic effects due to overdose.”

This is especially true for sensitive groups, such as cancer survivors. The National Institutes of Health issued a 2006 statement on the link between supplementation and increased risk of cancer recurrence or a secondary cancer. But a new study by Snyder showed that 75 percent of cancer survivors 65 years or older reported taking some form of supplement.

Put Food First

“Dietary supplements are just that -- a supplement,” says Snyder. “They can be expensive and completely unnecessary. If you do take a supplement, make sure not to take more than 100 percent of the daily values for nutrients. Tell your doctor, exercise caution, think moderation, and look to food first.”