Vitamins and other supplements should help your health, not harm it —in fact; the whole idea behind the campaign to “take your vitamins” is to provide your body with essential nutrients it might not be getting through your diet.

However, there are some vitamins and minerals that may have adverse effects on your health if you take them in the form of supplements, these effects can range from transient and unpleasant symptoms, to severe and life-threatening diseases; in the worst cases, certain vitamins may raise your risk of cancer.

So should you take any supplements? That depends on your overall health and risk factors for certain conditions. However, here are four nutrients that you probably shouldn’t take in the form of supplements:

1.     Iron.

Your body uses iron in your red blood cells, which you need to carry oxygen throughout your body. When you have too little iron — a condition called anemia — you’re frequently tired, and you probably lack much energy.

Nonetheless, taking iron in the form of a supplement can lead to indigestion and constipation or diarrhea. In addition, there’s some evidence that high levels of iron in your body may raise your risk of heart disease and cancer. Since your body stores iron efficiently, you shouldn’t add any extra unless you’re truly anemic.

2. Vitamin E.

A few years ago, vitamin E was touted as protective against certain kinds of cancer, especially prostate cancer. However, follow-up research found the opposite: men who were taking vitamin E supplements actually had a slightly higher risk of prostate cancer.

Medical experts also have reversed their earlier pronouncements that vitamin E can help ward off heart disease. One major research trial found that taking supplements of the vitamin didn’t ward off coronary artery disease, stroke or deaths from heart disease. Meanwhile, vitamin E supplements did increase the risk of heart failure in trial participants.

3. Vitamin A.

Your body needs vitamin A for healthy vision and to help produce barriers to bacteria and viruses in your respiratory, intestinal and urinary tracts. The nutrient also plays a role in your immune system, helping your white blood cells fight infections. Still, even though you need Vitamin A, consuming too much of the nutrient is potentially more dangerous than consuming too little. As with iron, your body stores vitamin A efficiently, and that can allow your levels to build too high. Symptoms of vitamin A overdose and toxicity include blurred vision, weak muscles and peeling skin. If you’re a woman and pregnant, large doses of vitamin A also pose a risk to your unborn baby.

4. Zinc.

A few years ago, natural health gurus started promoting zinc as a treatment for the common cold. Almost overnight, drugstore aisles filled up with zinc products — supplements and lozenges — intended to treat the sniffles. However, the evidence that zinc can shorten a cold’s duration is mixed, at best; only one or two small studies indicate a true benefit. Meanwhile, there’s mounting evidence that it’s very possible to overdose on zinc. Too much zinc can lower your levels of so-called “good” cholesterol, while also interfering with your body’s absorption of other important nutrients, including iron and magnesium.

The bottom line is, too much of certain beneficial vitamins and minerals can be harmful and even toxic. Rather than eating poorly and trying to make up the difference with these four nutrients or with others by taking supplements, it’s always better to get most or all of your essential vitamins and minerals through your diet.

Laino, C. (2012, May 23). Some Dietary Supplements Linked to Liver Damage. Retrieved March 19, 2014, from http://www.webmd.com/digestive-disorders/news/20120523/some-dietary-supplements-linked-to-liver-damage

Offit, P. A. (2013, June 8). Don’t Take Your Vitamins - NYTimes.com. Retrieved March 19, 2014, from http://www.nytimes.com/2013/06/09/opinion/sunday/dont-take-your-vitamins.html?_r=0

Thompson, D. (2014, February 21). Vitamin E, Selenium Supplements Might Double Chances of Prostate Cancer – WebMD. Retrieved March 19, 2014, from http://www.webmd.com/prostate-cancer/news/20140221/vitamin-e-selenium-supplements-might-double-chances-of-prostate-cancer