Zinc is a mineral essential to your good health. It is required for the normal function of nearly 100 different enzymes, healthy immune function, and normal growth and development. ZInc is also needed for cellular manufacture of proteins and genetic material, wound healing and the perception of taste and smell. Your body doesn’t store zinc, so regular intake is required to avoid a deficiency. Zinc toxicity is not a common problem, but can occur from overuse of supplements or significant environmental exposure. There are several short and long-term side effects of too much zinc in your blood.
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Acute Zinc Toxicity
Zinc is readily absorbed from your digestive tract. Ingestion of large amounts of zinc over a short period of time can result in acute zinc toxicity. Digestive system symptoms usually predominate, including abdominal cramps, nausea, vomiting, diarrhea and stomach irritation. Other possible symptoms include headache, irritability, fatigue and dizziness. Symptoms may begin within less an hour if a massive dose is ingested, such as with an accidental or intentional overdose. Management of acute toxicity focuses on removing the source of zinc exposure and treating symptoms as necessary.
Metal Fume Fever
Zinc can also enter the body through your lungs. Inhaling zinc dust or fumes -- from zinc welding or smelting, for example -- can cause an acute form of zinc toxicity known as metal fume fever. This syndrome usually begins within a few hours of exposure and is characterized by cough, chest tightness, muscle and joint pain, sore throat, headache and fever typically lasting 1 to 4 days.
Chronic Zinc Toxicity
Prolonged ingestion of zinc at doses of 100 to 150 mg daily can interfere with copper metabolism and lead to a deficiency in this important mineral in your body. More subtle changes are evident with laboratory testing at doses as low as 60 mg daily, according to the National Institutes of Health Office of Dietary Supplements. A low copper level leads to poor iron function, red blood cell abnormalities, reduced immune function and potentially harmful changes in your blood fat levels. Medical management involves removing the source of zinc overexposure, symptomatic treatment and maintaining future zinc intake below the recommended upper limit of 40 mg daily for adults.
Avoiding Excess Zinc Exposure
Laboratory testing for zinc can measure levels in your blood, feces, urine and hair. Hair analysis is most indicative of long-term exposure. Zinc toxicity from your diet alone is unlikely -- except in the case of excessive supplement use. Recognizing possible environmental sources of zinc can also help you avoid overexposure. If you live near a zinc mine or other industrial source, zinc could be present at high levels in your locally grown food, contaminating soil and home surfaces or in your drinking water if you have a private well. Talk with your healthcare practitioner or local health department to help answer questions concerning possible zinc toxicity.