Some risks of taking vitamins and minerals that you should know

Even though smart people you know take vitamins and minerals, these supplements can be dangerous in certain dosages and circumstances. Sometimes they can even kill. Even old friends like vitamins C and E can turn on you. Here are some risks associated with vitamins and minerals that you should know.

Yes. Though most are dangerous only at high doses.The government makes sure that the vitamin and mineral pills lining drugstore shelves have been tested for safety and efficacy, right? Wrong.

• If you thought that was the case, don't feel bad. A poll found that more than 50 percent of people believe that dietary supplements (from vitamins and herbs to fish-oil capsules) go through the same testing and approval procedures that prescription drugs undergo. That's not the case in the many countries.
• That means it's up to consumers and their doctors to decide if taking a certain supplement is a good idea.
• Fortunately, most vitamin and mineral supplements are dangerous only when they contain ultra-high doses of certain nutrients, or if you take too many of them.

Check with your doctor before taking a supplement because many common supplements can react dangerously with certain prescription drugs. Supplements can interfere with or even increase the action of a prescription drug, and the results can be dangerous.

• For example, folic acid can interact with anticonvulsant medications. And if you're taking a blood thinner such as warfarin (Coumadin) or aspirin, you shouldn't take vitamin E, vitamin K, garlic, fish oil or ginkgo biloba, all of which also thin the blood.
• Too much blood thinning could possibly cause bleeding in the brain. If you're taking a cholesterol-lowering statin drug and niacin to reduce your risk of heart disease, avoid antioxidant supplements (which may contain vitamin C, vitamin E, selenium and beta-carotene). They can reduce the gains in "good" HDL cholesterol produced by the statin drug and niacin.
• Finally, smokers should avoid supplements that contain more than 3,000 IU of vitamin A (or beta-carotene), which is about the amount you'll find in many multivitamins. Studies have found that taking supplements with high doses of beta-carotene can increase a smoker's risk of contracting lung cancer, though getting beta-carotene from foods such as spinach, kale, squash and apricots poses no risk.

At the end of the day, your best bet is to check with your doctor before taking any type of supplement to make sure you're taking a safe and effective dosage.