Play it safe when taking vitamins - Lake County News Sun

Dr. Anthony Komaroff www.AskDoctorK.com September 17, 2012 6:22PM

Copyright 2002 President and Fellows of Harvard College on behalf of HMS Media Services, Photo by Liza Green, HMS Media Services, Anthony Leader Komaroff, MD, Harvard Health Publications

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Updated: September 18, 2012 2:45AM

Dear Doctor K: I take vitamin and mineral supplements. Do I need to worry about getting too much of certain nutrients?

Dear Reader: Many people take individual vitamin and mineral supplements in addition to a powerful multivitamin. But ingesting too much of certain micronutrients can be dangerous. It’s harder â€"but not impossible â€" to get dangerously high amounts of micronutrients from food alone.

To play it safe, avoid taking more than the recommended dietary allowance (RDA) of any micronutrient through supplements. (To check the RDA for any supplement, visit: ods.od.nih.gov/factsheets/list-all/.)

It is especially important to avoid taking too much of the folloing vitamins and minerals:

VITAMIN A. Most of us get plenty of vitamin A in foods â€" liver, milk, eggs, carrots, spinach and many other foods. Too much vitamin A in supplements can harm bones and can lead to birth defects. . Too much beta carotene can also give your skin and eyes a yellowish hue.

VITAMIN E. Too much vitamin E can cause bleeding, headache, fatigue and blurred vision.

CALCIUM (FOR MEN). Recent studies have found that excess intake of calcium appears to increase the risk of prostate cancer. While not all scientists agree, I think that most men should avoid taking calcium supplements and should not consume too many dairy products. An exception is men who have osteoporosis, or thin bones, who may need a combination of calcium and vitamin D.

IRON. Large doses of iron supplements can trigger an iron overload. Some people inherit a genetic condition that causes them to absorb more iron from the gut than most people. This can damage body tissues and can raise the risk of heart disease, liver cancer, infections and arthritis. Your body can’t easily shed excess iron. Also, taking high doses of vitamin C allows your body to absorb more iron than it normally would. In my opinion, the only people who should take iron supplements are people who have a clear iron deficiency, as shown by blood tests.

ZINC. The RDA for zinc is 8 mg for women and 11 mg for men. Yet levels higher than 15 mg can trigger side effects, such as a depressed immune system, poor healing, hair loss and interference with taste and smell. It’s best to get zinc from food sources rather than supplements.

We have more information on dietary supplements in our Special Health Report, “The Truth About Vitamins and Minerals.” (Learn more about this report at AskDoctorK.com, or call 877-649-9457 toll-free to order it.)

Write to Dr. Komaroff at www.AskDoctorK.com