After iron, zinc it the second most abundant trace element in the human body. It is a divalent cation and the 30th element as well as the first element in group 12 of the periodic table. It is an essential micronutrient that plays a key role in the catalysis of over 100 enzymes such as alkaline phosphatase, lactic dehydrogenase, and RNA and DNA polymerase. It assists in the synthesis of RNA and DNA, cell proliferation and differentiation, and the stabilization of cell membranes and cell structures. Zinc exerts its gene regulatory and expressive effects through the formation of zinc finger proteins (ZnF).
The Role of Zinc in the Human Body
Zinc also plays a role in the regulation of the immune system. Being an essential element, it is not synthesized by the human body but must be ingested through food or mineral supplements. Some of the common food sources of zinc include beef, poultry, seafood, and grains, among others. In adults, normal serum zinc levels are between 70 and 250 ug/dl. After oral ingestion, zinc absorption occurs mainly in the ileum and duodenum and its binds to plasma proteins such as albumin in the blood. Following its metabolism, it is excreted mainly in the stool; some metabolites are also excreted in the urine and sweat, but to a significantly lower extent.“Zinc sulfate”. Available: https://go.drugbank.com/drugs/DB09322Maxfield, L., Crane, J.S., “Zinc Deficiency”, StatPearls. 2020. Available: https://www.ncbi.nlm.nih.gov/books/NBK493231/Saper, R.B., Rash, R., “Zinc: An Essential Micronutrient”, American Family Physician, vol.79 issue 9, pp.768 – 772. 2009. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2820120/#
Administration Methods of Zinc
Zinc is usually clinically administered in the form of zinc sulfate as a supplement. The most common routes of administration of zinc sulfate are oral and parenteral. Exogenous zinc administration is typically indicated in the management of zinc deficiency.
Symptoms of Zinc Deficiencies
With zinc playing a significant role in many of the body’s key processes, zinc deficiency can result in a variety of illnesses and medical disorders. Some of the clinical manifestations include, but are not limited to, the following:
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- Hair and weight loss.
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- Delayed wound healing and skin lesions such as oral lichen planus, pemphigus vulgaris, bullous pemphigoid, and epidermodysplasia verruciformis, among others.
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- Decreased taste sensation and loss of appetite.
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- Altered cognitive and motor performance in neonates and infants.
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- Increased susceptibility to infections due to decreased functionality in monocytes, neutrophils, granulocytes, and phagocytosis.
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- Exacerbation of hypertension as well as other cardiovascular diseases.
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- Delayed puberty and growth retardation in adolescents.
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- Osteoporosis as well as other abnormalities in bone mineralization and development.
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- Decreased folate absorption which may result in macrocytic megaloblastic anemia.
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- Mental lethargy and mood disorders.Mocchegiani, E., Romeo, J., Malavolta, M., Costarelli, L., Giacconi, R., Diaz, L., Marcos, A., “Zinc: Dietary intake and intake of supplementation on immune function in elderly”, Age, vol.35 issue 3, pp.839 – 860. June 2013. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636409/
While exogenous zinc supplements are generally well tolerated, there are some situations or circumstances that may warrant some degree of caution before it is administered. These include:
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- Renal impairment: Care should be exercised when administering zinc to individuals with renal compromise. As zinc is excreted in the urine, renal disease may impair its excretion in the urine and increase the likelihood of developing zinc toxicity.
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- Hypersensitivity reactions: Individuals may be hypersensitive to additional substances in the zinc supplement. Individuals with demonstrated hypersensitivity to any of the additional substances should not receive exogenous zinc supplements.
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- Drug interactions: Zinc is known to interact with a variety of other medications which may impair their efficacy. Extreme care should be exercised when administering zinc to individuals taking other medications at the same time. Some medications that have the potential to interact with exogenously administered zinc are quinolones, tetracyclines, and penicillamine; zinc inhibits the absorption of these medications from the intestine. Also, thiazide diuretics, when given concurrently with zinc, increases the renal excretion of zinc and may also deplete zinc levels in the tissue. It may be necessary to monitor serum zinc levels when administered in conjunction with other medications.“Zinc – Fact Sheet for Health Professionals”, National Institutes of Health, Office of Dietary Supplements. Available: https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/
Exogenous zinc sulfate has been assigned to the pregnancy category C by the Food and Drug Administration. Though there is the possibility of fetal harm, the likelihood of this occurring is very remote. Zinc can be used in pregnancy since the dangers of zinc deficiency is substantially greater than any risks that may occur from its administration. Zinc crosses the placenta to the fetus where it plays a role in fetal neurodevelopment, as previously stated. Additionally, zinc also crosses from nursing mothers to infants through breast milk during lactation.“Zinc sulfate Pregnancy and Breastfeeding Warnings”, Drugs. Available: https://www.drugs.com/pregnancy/zinc-sulfate.html#:~:text=Zinc%20sulfate%20has%20been%20assigned,age)%20is%20recommended%20during%20pregnancy.
Apart from the likelihood of developing hypersensitivity reactions to exogenous zinc, the common adverse effect to watch out for is zinc toxicity. This may occur through an increased ingestion of zinc or a reduced excretion. Toxic levels of zinc in the human body is typically associated with a marked decrease in serum copper levels. Some of the clinical features that may arise as a result of zinc toxicity are hematemesis, hematuria, acute tubular necrosis, sideroblastic anemia, granulocytopenia, diarrhea, and myelodysplastic syndrome, among others. If zinc toxicity occurs, the exogenous administration of zinc should be discontinued immediately, and measures should be initiated to bring the zinc levels back down within normal ranges.Agnew, U.M., Slesinger, T.L., “Zinc Toxicity”, StatPearls. Available: https://www.ncbi.nlm.nih.gov/books/NBK554548/
Store this medication at 68°F to 77°F (20°C to 25°C) and away from heat, moisture and light. Keep all medicine out of the reach of children. Throw away any unused medicine after the beyond-use date. Do not flush unused medications or pour down a sink or drain.
