Study reveals taking too many vitamins may increase cancer risk

Your mom always told you to take your vitamins, but that advice may be bad for your health.

Many studies show eating fruits and vegetables can reduce the risk of cancer and heart disease, but what about vitamins?

A new report reveals taking too many supplements can actually increase the risk of some cancers. "The idea was give people more vitamins and it would prevent cancer, but they find when they do a lot of these studies is it can do the exact opposite and it's hard to know what's safe," ABC News Chief Health and Medical Editor Richard Besser M.D., said.

Some vitamins are more dangerous than others to specific groups of people.

For instance, Besser says high doses of beta-carotene given to smokers can increase the risk for lung cancer.

Selenium given to people at risk for skin cancer can increase the risk for skin cancer.

For men, vitamin E can increase the risk of prostate cancer.

And excessive folic acid given to the elderly can increase the risk of colon cancer.

Besser says the best way to get your vitamins and minerals is through a balance diet. "Clearly eating a lot of fruits and vegetables is the way to go, but if you're a woman though and you're thinking of getting pregnant or are pregnant you need a multi-vitamin with folate. If you have a medical condition where you can't absorb all your nutrients you'll need a vitamin there and if you're on a special diet like someone who is vegan, there you need vitamin B12.

Besser says if you have any questions about vitamins, especially when it comes to interactions with other drugs, to talk with your doctor.