Zinc is a metal the body needs for normal growth and development. Zinc supplements may help with conditions such as the speeding of wound healing, decreasing the progression of macular degeneration and decreasing symptoms of the common cold. Although increased zinc consumption and supplemental use of the mineral is necessary for people with a deficiency, too much of the nutrient may cause medical problems. Consult your health care professional before increasing dietary zinc or taking zinc products.
Recommended Levels
The recommended daily allowance of zinc from foods is 11 mg for males and 8 mg for females, according to the Office of Dietary Supplements. Pregnant and lactating women need higher levels of zinc to help supply adequate amounts of zinc to the developing and growing child. Children under the age of 18 require between 2 mg and 11 mg, depending on age and gender. Individuals who do not get adequate amounts of zinc from food may need to take zinc supplements.
Possible Causes
Foods high in protein, such as oysters, beef, pork, peanuts and legumes, contain high amounts of zinc. Eating large amounts of zinc may increase the likelihood of increased levels in the body, but is not common. Inhaling zinc oxide fumes from an industrial source can cause toxic levels of zinc. Food poisoning related to storing food or beverages in a galvanized container may cause acute zinc toxicity, according to a study reported in "The American Journal of Clinical Nutrition." Additional causes of a zinc overdose include ingesting topical creams containing zinc and taking excessive amounts of supplemental zinc. Adults ingesting more than 40 mg of zinc per day may experience zinc toxicity, according to the Office of Dietary Supplements.
Symptoms
Symptoms of a zinc overdose include nausea, vomiting, diarrhea, abdominal cramping and epigastric pain. These gastrointestinal symptoms are commonly the first signals of an acute toxicity. Some people may experience a metallic taste in the mouth. Additional symptoms of a zinc overdose include fainting, dizziness, lethargy, jaundice and difficulty walking. Symptoms generally begin between three and 10 hours after ingesting a large amount of zinc, according to MedlinePlus.
Treatment and Considerations
Reducing dietary zinc consumption and discontinuing zinc supplements is the first step in reducing toxic levels of zinc in the body. People with a zinc overdose related to inhaling fumes from zinc oxide have lower zinc levels within 12 to 24 hours following the removal of the fumes, according to the Merck Manuals Online Medical Library. An overdose of zinc may cause a copper deficiency in the body. Additional long-term effects of chronic high levels of zinc include anemia and a weakened immune system.
References
- MayoClinic.com; Zinc Supplement:Side Effects; November 2010
- Merck Manuals Online Medical Library; Zinc; Dr. Larry E. Johnson; August 2008
- MedlinePlus; Zinc in Diet; Dr. Linda Vorvick; March 2009
- Office of Dietary Supplements: Zinc
- "The American Journal of Clinical Nutrition": Zinc Toxicity; Gary J. Fosmire; February 1990
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