Zinc is a trace mineral essential for human health.
Zinc is essential for numerous metabolic processes in the human body. It is a catalyst of more than 100 enzymes, and plays an important role in cell division, DNA and protein synthesis, wound healing, and normal immune function. Furthermore, it supports growth in development1.
Signs and Symptoms of Deficiency or Toxicity
Zinc deficiency is believed to be one of the most prevalent worldwide2. It occurs because zinc is not absorbed from the diet because of the presence of phytates or an excess in copper or iron3.
Symptoms of zinc deficiency include slowing or cessation of growth and development, delayed sexual maturation, skin rashes, chronic and severe diarrhea, impaired wound healing, diminished appetite, impaired taste, night blindness, behavioral distrubances, and impaired immune function 1,4.
Reported symptoms of zinc toxicity include abdominal pain, diarrhea, nausea, and vomiting, profuse sweating, weakness, rapid breathing, and headaches1,4.
Zinc is acknowledged to reduce the duration and severity of diarrhea. As such, mothers or other caregivers and health workers should provide children with 20 mg per day of zinc supplementation for 10-14 days (10 mg per day for infants under the age of six months) for the management of diarrhea6. There are no established WHO guidelines for zinc supplementation in adults to treat diarrhea. However, if a person chooses to have zinc supplementation to prevent a deficiency, it is best that they are taken 1 hour before a meal or 2 hours after.
Following are the common dosages used for the the preventive purpose9.
- Adult and teenage males: 9-15 mgs/day
- Adult and teenage females: 9 to 12 mg/day
- Pregnant females: 15 mg/day
- Breastfeeding females: 15 to 19 mg/day
- Children, 4 to 10 years: 5 to 10 mg/day
Following are the established upper limits for zinc per age group7.
- For infants:
- 0-5 months: 4 mg
- 6-11 months: 5 mg
- For children:
- 1-3 y.o.: 7 mg
- 4-8 y.o.: 12 mg
- 9-13 y.o.: 23 mg
- 14-18 y.o.: 34 mg
- For adults, 19 years and older: 45 mg
- For pregnant/lactating:
- 14-18 y.o.: 34 mg
- 19 years and older: 40 mg
Administration of zinc supplements together with tetracycline and quinolone antibiotics, biphosphonates may potentially reduce absorption of zinc and drug efficacy. Metal chelating agents, sodium valproate, and prolonged use of diuretics can also result in zinc deficiency4.
Sources of zinc include oysters, beef, crabmeat, pork, yoghurt, milk, cashews, chickpeas, almonds, peanuts, and cheese8.
(2) Wieringa FT, Dijkhuizen MA, Fiorentino M, Laillou A, Berger J. Determination of Zinc Status in Humans: Which Indicator Should We Use? Nutrients. 2015;7(5):3252-3263. doi:10.3390/nu7053252.
(3) Mayo Clinic Medical Laboratories. (n.d.). Test Catalog. Zinc, Serum. Retrieved from https://www.mayomedicallaboratories.com/test-catalog/Clinical+and+Interpretive/8620
(4) Higdon J, Drake VJ. (June 2013). Linus Pauling Institute. Micronutrient Information Center. Zinc. Retrieved from http://lpi.oregonstate.edu/mic/minerals/zinc#authors-reviewers
(5) King JC, Brown KH, Gibson RS, et al. Biomarkers of Nutrition for Development (BOND)—Zinc Review. The Journal of Nutrition. 2016;146(4):858S-885S. doi:10.3945/jn.115.220079.
(6) World Health Organization. (June 15, 2017) Zinc supplementation in the management of diarrhoea. Retrieved from http://www.who.int/elena/titles/zinc_diarrhoea/en/
(7) Philippine Dietary Reference Intakes. 2015. Department of Science Technology-Food and Nutrition Research Institute.
(8) Linus Pauling Institute. Oregon State University. (n.d.). Micronutrients for Health. Retrieved from http://lpi.oregonstate.edu/sites/lpi.oregonstate.edu/files/pdf/mic/micronutrients_for_health.pdf
(9) Micromedex. (n.d.). Drugs and Supplements. Zinc Supplement (Oral Route, Parenteral Route). Retrieved from https://www.mayoclinic.org/drugs-supplements/zinc-supplement-oral-route-parenteral-route/proper-use/drg-20070269