Zinc is an essential nutrient that contributes to a variety of the body's functions, including cell reproduction, immunity, synthesis of proteins, vision, protection against free radical damage and repair of wounds. But despite its many benefits, zinc is a nutrient that, if taken in excess, can pose health risks, including some that are very serious.
Getting Enough Zinc
The best zinc sources are oysters and other seafood, red meat and poultry. For most of us, a healthy diet will provide all of the zinc we need. For those with deficiencies, supplementation under the direction of a doctor will probably be advised. But caution is warranted because higher than recommended dosages can cause health problems.
Knowing How Much is Too Much
The U.S. Food and Drug Administration has determined that 40 mg a day of zinc is safe. Excess zinc side effects include reduced HDL, or good cholesterol, levels and a weakened immune system. Other side effects are nausea, vomiting, dehydration, stomach upset, stomach ulcers, and a disease of the prostate gland known as prostatis. Higher risk for cancer, loss of sex drive, anemia, impotence, hair loss, muscle spasms, back pain, menstrual pain, insomnia and irritability are other possible zinc side effects. Chronic oral zinc supplementation in excess of 150 mg a day has led to stomach upset, a lingering metallic taste, blood in the urine and fatigue.
Zinc in Other Forms
While the findings above have been based on oral use of zinc, the mineral has also been studied in other forms. There have been reports from people using zinc lozenges that they experienced nausea and stomach upset, mouth irritation and a bad taste. In at least 10 people, zinc nasal spray has reportedly led to a severe to complete loss of smell. For some of those, loss of smell was long-term to permanent. However, there are no documented side effects from zinc in topical form when it is used as recommended.
Zinc Interference With Other Nutrients
Excess zinc is known to interfere with our absorption of the essential minerals iron, magnesium and copper. For these reasons, you are best off with a good mineral supplement that includes all essential minerals in balance.
Zinc Sulfate Side Effects
Zinc sulfate is recommended by medical professionals for individuals who are deficient in zinc. The most common side effects from this specific form of zinc supplements are upset stomach, nausea and heartburn. Less common side effects have included fever, fatigue, sore throat and mouth sores.
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