Diseases & Conditions
Zinc is widely distributed in the body—in bones, teeth, hair, skin, liver, muscle, white blood cells, and testes. It is a component of more than 100 enzymes, including those involved in the formation of RNA (ribonucleic acid) and DNA (deoxyribonucleic acid).
The level of zinc in the body depends on the amount of zinc consumed in the diet. Zinc is necessary for healthy skin, healing of wounds, and growth. Much of the zinc consumed in the diet is not absorbed.
Zinc deficiency has many causes, including diet, various disorders, alcoholism, and diuretics. People lose their appetite and hair and may feel sluggish and irritable. Measuring the zinc level in blood is available but is not a good test for zinc status. Zinc supplements taken by mouth can cure the deficiency.
Many conditions can increase the risk of developing zinc deficiency.
Did You Know...
Lack of zinc can weaken the immune system and make wounds heal more slowly. Zinc deficiency is common among older people who live in institutions and people who are homebound.
What Can Cause Zinc Deficiency?
Dietary deficiency of zinc is uncommon in developed countries
Bloodstream infection (sepsis)
Chronic kidney disease
Disorders that impair absorption (malabsorption)
Burns if severe
Intravenous feedings for a long time
In acrodermatitis enteropathica, a rare hereditary disorder, zinc cannot be absorbed. This disorder may result in diarrhea, hair loss, and zinc deficiency.
Early symptoms include a loss of appetite and, in infants and children, slowed growth and development. People may lose their hair in patches. They may feel sluggish and irritable. Taste and smell may be impaired. Rashes may develop. In men, sperm production may be reduced. The body's immune system may be impaired, and wounds may heal more slowly and less completely.
If pregnant women have zinc deficiency, the baby may have birth defects and may weigh less than expected at birth.
In acrodermatitis enteropathica, symptoms usually appear when an affected infant is weaned.
Diagnosis and Treatment
Doctors suspect zinc deficiency based on the person's circumstances, symptoms, and response to zinc supplements. Blood and urine tests do not accurately measure zinc status.
Zinc supplements taken by mouth until symptoms disappear.
People rarely consume too much zinc. Usually, zinc excess results from consuming acidic foods or beverages packaged in a zinc-coated (galvanized) container. In certain industries, inhaling zinc oxide fumes can result in zinc excess.
People may have a metallic taste in the mouth, as well as nausea, vomiting, and diarrhea. Consuming 1 gram or more—about 70 times the recommended daily allowance (RDA)—daily may be fatal. Inhaling zinc oxide fumes can cause rapid breathing, sweating, fever, and metallic mouth taste—a disorder called metal fume fever. Consuming too much zinc for a long time can reduce the absorption of copper, cause anemia, and impair the immune system.
Doctors suspect the diagnosis based on the person's circumstances and symptoms.
Treatment involves reducing zinc consumption. People with metal fume fever usually recover after being in a zinc-free environment for 12 to 24 hours.
Last full review/revision August 2008 by Larry E. Johnson, MD, PhD
Source: The Merck Manual Home Edition