Excess Zinc

Zinc is an essential trace element that plays an important role in cellular metabolism and proper functioning of the immune system. The National Institute of Health's Office of Dietary Supplements recommends 2 to 12 mg of the zinc per day, depending on the age and condition of the patient. Foods such as oysters, red meat, beans and nuts are good sources of the mineral. Zinc supplements may help prevent and treat a variety of conditions including respiratory tract infections, anemia, macular degeneration, ADHD and erectile dysfunction. However, do not use the supplements without consulting your doctor, as they are associated with a several side effects.

Prostate Cancer

High doses of zinc supplements can lead to elevated levels of the mineral in the prostate and may increase the risk of prostate cancer, according to a study published in the July 2003 issue of the "Journal of National Cancer Institute." Researchers found that men who took more than 100 mg of zinc per day, or took zinc supplements for more than 10 years, might have a higher chance of developing the cancer. Hence, always talk to a doctor before using zinc supplements.

Absorption of Drugs

Zinc may reduce your body's ability to absorb quinolone and tetracycline antibiotics such as ciprofloxacin, ofloxacin, minocycline and demeclocycline, says the University of Maryland Medical Center. It can also affect the absorption of pain medications such as ibuprofen. Tell your doctor if you take these medications with zinc supplements.

Copper Deficiency

A study published in the January 2005 issue of the "American Journal of Clinical Pathology" suggests that excessive use of zinc can lead to a deficiency of copper, another essential trace element. This can lead to neutropenia, or low white blood cell count, and sideroblastic anemia, defined by the formation of abnormal red blood cells. This causes fatigue, dizziness, pale skin and increased risk of infections. Pregnant and breast-feeding women should take zinc supplements only under the supervision of a doctor as the excess zinc may pass on their baby and lead to copper deficiency.

Loss of Smell and Taste

The use of zinc nasal sprays, according to the American Cancer Society, can lead to loss of smell and taste. This loss is temporary and does not occur due to the use of oral zinc supplements. However, several manufacturers have discontinued making zinc nasal sprays and it is best to consult a physician before using one.

Genitourinary Complications

High doses of zinc can also lead to increased hospitalization due to urinary tract problems, says a study published in the February 2007 issue of "The Journal of Urology." The genitourinary complications included prostatic hyperplasia/urinary retention, or benign prostatic hyperplasia, urinary tract infection, urinary lithiasis and renal failure. The study found these complications upon consumption of 80 mg of zinc supplement per day. So, do not use zinc supplements without talking to a doctor.