Zinc has key roles in producing energy in your body, cell metabolism, building DNA and RNA and regulating your immune system. You also need it for smelling, tasting and wound healing. According to the American Cancer Society, zinc supplement supporters clam it can reduce the duration and severity of colds, protect against cancer, decrease allergy or asthma symptoms, fortify your skin or shrink enlarged prostate glands. It’s also promoted as a good antioxidant. However, too much zinc will cause adverse effects in your body and can even be dangerous, notes the U.S. Office of Dietary Supplements.
Taking too much zinc can cause vomiting, nausea, loss of appetite, diarrhea, headaches and abdominal cramps, according to ODS. Adults should take in no more than 40 mg zinc daily. Taking in excessive amounts, such as 4 g zinc gluconate, which equals 570 mg elemental zinc, can lead to severe vomiting within 30 minutes. Zinc overdose can lead to kidney failure that will cause death, according to ACS.
You can suffer zinc due to a single overdose or by ingesting too much zinc over a period of time, according to ACS. If you are seeking to boost your immune system, taking too much zinc will backfire. Overdose will lead to a weakened immune system as well as fatigue, chills and fever. If you take high doses over long periods of time, you may also increase your risk for urinary tract problems such as infections. An intake of 100 to 300 mg daily can cause chronic toxicity, according to the Sloan-Kettering Memorial Cancer Center in New York. Ingesting more than 100 mg daily may increase your risk of prostate cancer.
Ingesting too much zinc can lead to changes in the way iron works in your body, anemia, low copper levels and low levels of "good" HDL cholesterol, according to ACS. It also can cause leukopenia, or a low white blood cell count, according to the National Institutes of Health. Zinc also reduces your body’s ability to absorb antibiotics. Doses of 150 to 450 mg daily of zinc are linked to such effects, according to ODS. You’ll find zinc naturally in meats, seafood, nuts, cheese, eggs, and grains.