The essential mineral zinc is available in food and supplements. Although zinc supplements are claimed to be useful for a variety of health conditions, high doses can be toxic. MedlinePlus, a website provided by the National Library of Medicine, discourages taking zinc supplements on a routine basis unless your health-care provider recommends you do so.
Intake Level
You only need small amounts of zinc for health, and the mineral is easy to obtain in necessary amounts from foods such as meat, seafood, eggs, nuts and grains. The Food and Nutrition Board at the Institute of Medicine has set a tolerable upper intake level, or UL, of 40 mg of elemental zinc per day. The percentage of elemental zinc in supplements depends on the form; the Office of Dietary Supplements provides the example of 220 mg of zinc sulfate containing 50 mg of elemental zinc. You can find the elemental zinc content by checking the supplement facts label on the container.
Adverse Effects
Taking zinc supplements on a regular basis can cause digestive effects such as a metallic taste, nausea, vomiting and diarrhea. Taking more than the UL may cause coughing, stomach pain, severe nausea and vomiting, headache, fatigue and fever. More severe effects may include kidney and stomach damage. People with HIV or AIDS should not take any zinc supplements, as it could shorten lifespan in these patients, according to MedlinePlus.
High Doses
Taking high doses of 150 mg to 450 mg of zinc per day can cause many health problems, notes the American Cancer Society. These types of doses are associated with anemia, low copper levels, impaired immune system functioning, problems with the way iron works in the body, an increased risk of urinary tract infections and other urinary tract problems, and low levels of high-density lipoprotein cholesterol, known as "good" cholesterol." At least one fatality due to kidney failure has been associated with a zinc overdose of of 2011, according to the American Cancer Society. MedlinePlus identifies 10 g or more of zinc as a single dosage that could prove fatal.
Cancer Risk
Men who take more than 100 mg of supplemental zinc per day or who take any dosage of zinc supplements for 10 or more years double their risk of developing prostate cancer, according to MedlinePlus. In addition, taking a zinc supplement in combination with large doses of multivitamins may increase the risk of dying from this disease.
Member Comments