Zinc is a trace element that is considered a micronutrient, meaning a nutrient needed in very small amounts. It is found in almost every living cell. The significance of zinc in human nutrition and public health was recognized relatively recently (1961), and it is now considered to have a wide range of essential biological roles in maintaining life and health.


Zinc is considered essential to maintain health. It is required for the activity of numerous metalloenzymes involved in metabolism, maintains the immune system that protects the body against disease, and also supports normal growth and development during pregnancy, childhood, and adolescence. It plays three crucial roles:

Additionally, zinc has the following functions:

Recent research reports indicate that zinc has been found to play a role in cell death (apoptosis) with implications for growth and development, as well as in a number of chronic diseases. Zinc is also actively taken up by synaptic vesicles that store the neurotransmitters released by nerve cells, suggesting a new role in neuronal activity and memory.


Zinc is found in the body in a form bound to proteins within cells, especially in the nucleus and cell membranes. The adult body contains about 1.5–2.5 g of zinc bound to various proteins. They occur in specialized areas of the brain that produce the chemical substances that can send messages from one nerve cell to another (neurotransmitters). Zinc is also found in the pancreas, adrenal gland, bones, liver, prostate, and in the reproductive organs. Most of the zinc (75–88%) in blood is found in a red blood cell metalloenzyme called carbonic anhydrase. In the plasma, zinc is bound to proteins, such as alpha-2-macroglobulin, albumin, transferrin and ceruloplasmin.



Recommended dietary allowance (mg)

Tolerable upper intake level (mg)

Children 0-6 mos.

2 (AI)


Children 7-12 mos.



Children 1-3 yrs.



Children 4-8 yrs.



Children 9-13 yrs.



Boys 14-18 yrs.



Girls 14-18 yrs



Men 19≥ yrs.



Women 19≥ yrs.



Pregnant women 18≤ yrs.



Pregnant women 19≥ yrs.



Breastfeeding women 18≤ yrs.



Breastfeeding women 19≤ yrs.



AI = Adequate intake

mg = milligram

SOURCE: Office of Dietary Supplements. National Institutes of Health. “Zinc: Fact Sheet for Health Professionals.” https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional (accessed April 21, 2018).

Zinc is found in a wide variety of foods. Oysters are the richest zinc source per serving, but since they are not consumed regularly in the American diet, red meat and poultry provide the majority of dietary zinc. Other good zinc sources include beans, nuts, certain seafood, whole grains, fortified breakfast cereals, and dairy products. Zinc absorption is more efficient from a diet high in animal protein than a diet rich in plant proteins. Phytates, which are found in whole grain breads, cereals, legumes, and other products, are believed to decrease zinc absorption. Some good food sources of zinc include (per 1 oz. serving, or as indicated):

The Recommended Dietary Allowance (RDA) for zinc is:

Zinc in nutritional supplements is available as zinc gluconate, zinc oxide, zinc aspartate, zinc picolinate, zinc citrate, zinc monomethionine and zinc histidine. They are distributed as stand-alone or combination products, such as tablets, capsules, or liquids.


Sources of zinc.

Sources of zinc.

Fortified foods include many types of breakfast cereals that make it easier to consume the RDA for zinc. However, they also make it easier to consume too much zinc, especially if zinc supplements are also taken. Anyone considering zinc supplementation should first consider whether their needs could be met by dietary zinc sources and from fortified foods. Intakes between 150 and 450 mg of zinc per day lead to copper deficiency, impaired iron function, reduced immune function, and reduced levels of high-density lipoproteins, also known as “good cholesterol.” A few isolated cases of acute zinc toxicity have been reported for food or beverages contaminated with zinc present in galvanized containers. Single doses of 225–450 mg of zinc are known to induce vomiting. Milder gastrointestinal distress has been reported at doses of 50–150 mg/day of supplemental zinc.


The simultaneous administration of zinc supplements and certain antibiotics, such as tetracyclines and quinolones, may decrease absorption of the antibiotic with potential reduction of their action. To prevent this interaction, it is recommended to take the zinc supplements and antibiotics at least two hours apart. Metal chelating agents, like penicillamine, used to treat copper overload in Wilson disease, and diethyle-netriamine pentaacetate (DTPA), used to treat iron overload, can lead to severe zinc deficiency. Anticonvulsant drugs, such as sodium valproate, may also cause zinc deficiency. The prolonged use of diuretics may increase urinary zinc excretion, resulting in increased zinc losses. A medication used to treat tuberculosis, ethambutol, has been shown to increase zinc loss in rats.

Interactions of zinc taken with other supplements are as follows:

Uptake by the digestive tract.
Acrodermatitis enteropathica—
A genetic disorder resulting from the impaired uptake and transport of zinc in the body.
Water-soluble proteins that can be coagulated by heat and are found in egg white, blood serum, milk.
Antioxidant enzyme—
An enzyme that can counteract the damaging effects of oxygen in tissues.
A blue copper containing dehydrogenase protein found in serum that is apparently involved in copper detoxification and storage.
Chelating agent—
An organic compound in which atoms form more than one bond with metals in solution.
The material inside the nucleus of cells that carries genetic information. The scientific name for DNA is deoxyribonucleic acid.
Enzymes are proteins and vitally important to the regulation of the chemistry of cells and organisms.
Altered by addition of vitamins or minerals.
Gene expression—
The process by which the coded information of a gene is translated into the proteins or RNA present and operating in the cell.
A sulfur-containing amino acid produced by enzymatic or acid hydrolysis of proteins. Supplements are used as antioxidants.
An essential amino acid important for the growth and repair of tissues.
Proteins present in blood plasma. The five major families are: chylomicrons, very low-density lipoproteins (VLDL), intermediate-density lipoproteins (IDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL).
An enzyme that contains a tightly bound metal ion, such as cobalt, copper, iron or zinc.
Oxidative stress—
Accumulation in the body of destructive molecules such as free radicals that can lead to cell death.
The liquid part of the blood and lymphatic fluid. Plasma is 92% water, 7% protein, and 1% minerals.
A chemical similar to DNA from which proteins are made. Unlike DNA, RNA can leave the nucleus of the cell.
Short bowel syndrome—
Problems related to absorbing nutrients after removal of part of the small intestine.
Sickle cell anemia—
Genetic disorder in which red blood cells take on an unusual shape, leading to other problems with the blood.
Synaptic vesicles—
Also called neurotransmitter vesicles, these pouches store the various neurotransmitters that are released by nerve cells into the synaptic cleft of a synapse.
A protein synthesized in the liver that transports iron in the blood to red blood cells.
Ulcerative colitis—
Inflammation of the inner lining of the colon, characterized by open sores that appear in its mucous membrane.


In the case of zinc deficiency, oral zinc therapy usually results in the complete disappearance of symptoms, but it must be maintained indefinitely in individuals with the acrodermatitis enteropathica.

Excessive intake can be corrected by bringing levels back to the RDA values.


It has been estimated that 82% of pregnant women worldwide are likely to have inadequate zinc intakes. Zinc deficiency has been associated with a number of pregnancy complications, including low birth weight, premature delivery, and labor and delivery complications.

The adverse effects of zinc deficiency on immune system function are also likely to increase complications in children who have infectious diarrhea. Persistent diarrhea contributes to zinc deficiency and malnutrition. Recent research has shown that zinc deficiency may also increase the harmful effects of toxins produced by diarrhea-causing bacteria like E. coli. Zinc supplementation in combination with drinking plenty of liquids has also been shown to significantly reduce the duration and severity of childhood diarrhea.

Parental concerns


See also Veganism ; Vegetarianism .



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MedlinePlus. “Zinc.” U.S. National Library of Medicine, National Institutes of Health. https://medlineplus.gov/druginfo/natural/982.html (accessed April 24, 2018).

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Academy of Nutrition and Dietetics, 120 South Riverside Plz., Ste. 2000, Chicago, IL, 60606-6995, (312) 899-0040, (800) 877-1600, amacmunn@eatright.org, http://www.eatright.org .

Food and Nutrition Information Center, National Agricultural Library, 10301 Baltimore Ave., Rm. 105, Beltsville, MD, 20705, (301) 504-5414, Fax: (301) 504-6409, fnic@ars.usda.gov, http://fnic.nal.usda.gov .

Office of Dietary Supplements, National Institutes of Health, 6100 Executive Blvd., Rm. 3B01, MSC 7517, Bethesda, MD, 20892-7517, (301) 435-2920, Fax: (301) 480-1845, ods@nih.gov, http://ods.od.nih.gov .

U.S. Food and Drug Administration, 10903 New Hampshire Ave., Silver Spring, MD, 20993-0002, (888) INFO-FDA (463-6332), http://www.fda.gov .

Monique Laberge, PhD
Revised by Laura Jean Cataldo, RN, EdD

  This information is not a tool for self-diagnosis or a substitute for professional care.