Recent studies show that supplements sometimes have the opposite of the advertised effect.

Vitamin pills are good for you. Your body needs vitamins, and they’re a supplement for your diet. Unlike calories or fats, you can’t really get enough of them, so it doesn’t matter if you go over the recommended daily value. Right?

Turns out, probably not. In a New York Times piece, a Philadelphia hospital chief calls out vitamins supplements, saying that they can actually be harmful for you.

And there are numerous studies to back it up:

Two studies by the New England Journal of Medicine in 1994 and 1996, concluding that vitamins E and A respectively, as well as beta carotene, can increase the chance of lung cancer.

The Annals of Internal Medicine concluded in a 2005 study that Vitamin E “increased the risk of death.”

A compilations of studies based on 78 trials, published by the independent Cochrane Collaboration, concluded that beta-carotene, vitamin A and vitamin E actually increased mortality

The studies all point to the same thing: vitamins are antioxidants, which the body makes naturally to balance out free radicals. Free radicals can damage DNA, cells, and arteries, and are associated with old age, cancer and heart disease.

It would seem logical that the more antioxidants we have in our body, the less cancer and disease we have. However, it’s not that simple. Free radicals actually eat bacteria, as well as new cancer cells. So if we take too many antioxidants, we have less free radicals, and the balance tips the other way, leaving us more prone to what we were trying to prevent.

Vitamins don’t come with a warning about this, however, for a simple reason: in 1976, after extensive lobbying, Congress passed a law that included a provision which barred the Food and Drug Administration (FDA) from regulating the potency or establishing a standard of identity for vitamin products.

In other words, the FDA is legally prevented from warning you that vitamin supplements can be potentially harmful.

However, in its “Dietary Guidelines for Americans” handbook, the agency states that nutrient needs should “be met primarily through consuming foods, with supplementation suggested for certain sensitive populations.”

Do you take vitamin supplements, or do you depend on your diet? Tweet @curiousmatic