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Zinc Toxicity Signs and Symptoms

By , About.com Guide

Updated May 15, 2013

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zinc

Zinc may become toxic if taken in large amounts.

Guerra
Zinc is a dietary mineral your body needs for a variety of biochemical reactions to occur. It's often taken as a dietary supplement because it may work in the body as an antioxidant. For example, zinc is part of the antioxidant formula used in the U.S. National Eye Institute's Age-Related Eye Diseases Study that was completed in 2001.

Taking too many zinc supplements all at once can cause nausea, vomiting, cramps, diarrhea and headaches. Taking megadoses of zinc every day for a long period of time can cause problems with copper and iron, damage the immune system and reduce HDL cholesterol levels. Zinc supplements can also interact with certain types of medications.

The U.S. Institutes of Medicine set the daily tolerable upper intake (UL) for vitamins and minerals. The UL is the maximum level you can take every day (from both foods and supplements) that should not cause any health problems.

Daily Tolerable Upper Intakes for Zinc

  • Adults: 40 milligrams per day
  • Teens: 34 milligrams per day
  • Children ages 9 to 13: 23 milligrams per day
  • Children ages 4 to 8: 12 millgrams per day
  • Children ages 1 to 3: 7 milligrams per day
  • Infants ages 7 to 12 months: 5 milligrams per day
  • Infants up to 6 months: 4 milligrams per day
Dietary zinc is found in meats and plant-based foods that are high in protein, such as seafood, dairy products, poultry, legumes, nuts and seeds. Zinc deficiency can cause problems with your immune system and affect your ability to taste your foods. If you believe you have zinc deficiency symptoms, you need to see a healthcare provider before taking large amounts of zinc supplements.

Sources:

Institutes of Medicine, National Institutes of Health. "Dietary Reference Intakes: Elements." Accessed July 16, 2012. http://iom.edu/~/media/Files/Activity%20Files/Nutrition/DRIs/DRI_Elements.pdf.

National Eye Institute, National Institutes of Health. "Age-Related Eye Disease Study--Results." Accessed July 16, 2012. http://www.nei.nih.gov/amd/.

Office of Dietary Supplements, National Institutes of Health. "Dietary Supplement Fact Sheet: Zinc." Accessed July 16, 2012. http://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/.

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