What is zinc?

Zinc is the second most abundant trace metal in the human body with a total amount in the body of 2-4 grams. Zinc levels are higher in the bone and eyes than in the blood and since zinc cannot be stored, it has to be taken up daily from food or as a nutritional supplement in order to assure a sufficient supply. Foods that contain zinc include oysters, red meat, poultry, beans, nuts, seafood (crab, lobster), and whole grains. Zinc deficiency is very common with almost 2 billion people being affected worldwide, particularly in developing countries. Even in developed countries, zinc deficiency is common in the elderly.¹

What are the functions of zinc?

Zinc is involved in numerous processes including growth and development, stabilization of cell membranes, cell proliferation and cell death, protein synthesis, DNA formation, > 300 enzymatic reactions, immune function, and wound healing.²

With regards to immune function in the period early after surgery, injury, or sports, innate immune mechanisms (immunity that is naturally present and is not due to prior exposure) are activated leading to an influx of white blood cells into the wound and the production of inflammatory mediators (cytokines and chemokines).³ If an infectious agent had been encountered by the patient prior to surgery itself, the acquired or adaptive immune system may also be activated. Zinc deficiency decreases the activity of the cells of the innate immune system, including granulocytes, monocytes, and macrophages resulting in weakening of important immune functions such as chemoattraction (movement of immune cells toward the site of infection) and phagocytosis (process by which immune cells engulf other bacteria or other infectious particles) or cytotoxicity (killing of infected cells).⁴ Zinc deficiency also impairs the cells (T-cells, B-cells) of the adaptive immune system by inducing a decrease in the numbers of these cells and in antibody production.²

Zinc also plays a major role in regulating every phase of the wound healing process including blood coagulation, immune response and inflammation, repair of cell membranes, restoration of skin tissue, formation of new blood vessels, and scar formation.⁵ It is required for collagen and protein synthesis and cell proliferation – essential elements for tissue regeneration.

What is the suggested dose of zinc?

The recommended dietary allowance for adult men and women is 11 mg/day and 8 mg/day of zinc, respectively. The Upper Intake Level (maximum daily intake unlikely to cause harmful effects on health) for zinc is 40 mg daily for all males and females over 19 years of age.⁶

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3. Dabrowska AM, Slotwinski R. The immune response to surgery and infection. Cent Eur J Immunol. 2014;39(4):532-537.
4. Maares M, Haase H. Zinc and immunity: An essential interrelation. Arch Biochem Biophys. 2016;611:58-65.
5. Lin PH, Sermersheim M, Li H, Lee PHU, Steinberg SM, Ma J. Zinc in Wound Healing Modulation. Nutrients. 2017;10(1).
6. Zinc. https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/. Accessed May 14, 2020, 2020.