This article by Men?s Fitness.com says so:

Mom always said to take your vitamins. But she didn’t mean overdo it. Thirty-five percent of adults swallow a multivitamin on a regular basis, but several studies warn that an abundance of extra nutrients may not be as good for the body as previously suspected. Just check out the data.

DIABETES: While vitamin K and thiamine appear to help reduce risk factors, scientists warn that selenium in vitamins may increase the risk of type-2 diabetes.

PROSTATE CANCER: Too many multis may increase your risk of developing a form of fatal prostate cancer, according to data from the National Cancer Institute.

LUNG DISEASE: Multivitamins don’t protect against lung cancer, say scientists at the University of Washington. (In fact, too much vitamin E may increase the risk.)

LONGEVITIY: Perhaps most alarmingly, vitamin supplements may increase your overall mortality risk. So says a recent Danish review of 67 studies involving more than 200,000 participants. After analyzing the data, researchers found that people taking vitamins were 4% more likely to die during the course of the study than people who weren’t taking them. Yikes.

THE BOTTOM LINE: If your diet sucks, a multi may help. But if you already eat well
and buy fortified cereals and breads, you’re likely getting all the nutrients you need.

Interesting. Like most Americans who believe that they?re taking an active role in their health, I ingest a multivitamin on a daily basis (and actually, I take them on a nightly basis). But I don?t know if this article is enough to scare me away from taking them every day.

I wish the article had provided more detail as to the appropriate amount of times a week it?s okay to take a multivitamin. Based on that last paragraph, the article would almost lead you to believe that you should take a multivitamin on the days you can?t eat as healthy as you should.