Zinc is an essential trace element necessary for the proper functioning of various aspects of metabolism. Zinc participates in the regulation of cell proliferation in several ways, influence cell division and proliferation. In animals fed a zinc-inadequate diet, growth is reduced within 4-5 days. (1) Zinc regulates cell proliferation in several ways and influences the hormonal regulation of cell division. Specifically, the pituitary growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis is responsive to zinc status and it appears to be essential for IGF-I induction of cell proliferation. Overall, the evidence suggests that reduced zinc availability affects membrane signaling systems and intracellular second messengers that coordinate cell proliferation in response to IGF-I. Zinc plays a crucial role in cell division and cell growth, so it benefits muscle repair and growth by making it possible for the body to heal itself and maintain strength in the muscular and skeletal systems. (2) Zinc benefits muscle mass by increasing the amount of testosterone production ability in the body following exercise. Because it enhances the conversion rate of androstenedione to testosterone. 

Zinc is also critical for the development and function of immune cells. (3) Researchers found in a study in Cell Reports, that a protein called NF-kB lured zinc into the immune cells that responded fastest to fight infection. Once inside, the zinc then put the brakes on further activity in the NF-kB pathway, slowing down the immune response and limiting the amount of inflammation. For example, a review of seven studies demonstrated that 80–92 mg per day of zinc may reduce the length of the common cold by up to 33%. (4)

A study in Beijing in 2016 revealed the correlation between zinc and height. According to a study, compared with those (143.06 ± 33.76 μmol/L) in the taller group, zinc concentration (131.30 ± 40.75 μmol/L) in the shorter group was significantly lower at age 6–12 months. (5) Height was positively correlated with the zinc level in children aged 6–12 months. This study also indicated zinc levels were also positively correlated with calcium, magnesium, and iron concentrations in children aged 6–36 months. 

In addition, zinc affects learning and memory and helps in recovery and healing wounds. Zinc is commonly used in hospitals as a treatment for burns, certain ulcers and other skin injuries. (6) In fact, the skin holds about 5% of a relatively high amount of body's zinc content. (7) While a zinc deficiency can slow wound healing, supplementing with zinc can speed recovery in people with wounds. For example, in a 12-week study with 60 people with diabetic foot ulcers, those treated with 200 mg of zinc per day experienced significant reductions in ulcer size compared to a placebo group. (8) Research conducted at the University of Toronto suggested that zinc has a crucial role in regulating how neurons communicate with one another, affecting how memories are formed and how we learn. (9) 

Also, studies suggest that people with acne tend to have lower levels of zinc. (10) Both topical and oral zinc treatments can effectively treat acne by reducing inflammation, inhibiting the growth of P. acnes bacteria and suppressing oily gland activity. (11) In addition, Zinc is an effective anti-inflammatory and antioxidant agent, helping fight oxidative stress and decrease the chance for disease development, making it useful as a natural cancer treatment. 

References: 

1. MacDonald RS. The role of zinc in growth and cell proliferation. J Nutr. 2000 May; 130 (5 Suppl): 1500S-8S. 

2. Giugliano R, Millward DJ. The effects of severe zinc deficiency on protein turnover in muscle and thymus. Br J Nutr. 1987 Jan; 57 (1):139-55. 

3. Ananda S Prasad. Zinc in Human Health: Effect of Zinc on Immune Cells Mol Med. 2008 May-Jun; 14 (5-6): 353–357. 

4. Hemilä H. Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage. JRSM Open. 2017 May 2; 8 (5): 2054270417694291. 

5. Yin Y, Li Y, Li Q, Jia N, Liu A, Tan Z, Wu Q, Fan Z, Li T, Wang L. Evaluation of the Relationship Between Height and Zinc, Copper, Iron, Calcium, and Magnesium Levels in Healthy Young Children in Beijing, China. Biol Trace Elem Res. 2017 Apr; 176 (2): 244-250. 

6. Surajit Bhattacharya, R. K. Mishra. Pressure ulcers: Current understanding and newer modalities of treatment Indian J Plast Surg. 2015 Jan-Apr; 48 (1): 4–16. 

7. Pei-Hui Lin, Matthew Sermersheim, Haichang Li, Peter H. U. Lee, Steven M. Steinberg, Jianjie Ma. Zinc in Wound Healing Modulation Nutrients. 2018 Jan; 10 (1): 16. 

8. Momen-Heravi M, Barahimi E, Razzaghi R, Bahmani F, Gilasi HR, Asemi Z. The effects of zinc supplementation on wound healing and metabolic status in patients with diabetic foot ulcer: A randomized, double-blind, placebo-controlled trial. Wound Repair Regen. 2017 May; 25 (3): 512-520. 

9. Enhui Pan, Xiao-an Zhang, Zhen Huang, Artur Krezel, Min Zhao, Christine E. Tin-berg, Stephen J. Lippard, James O. McNamara Vesicular zinc promotes presynaptic and inhibits postsynaptic long term potentiation of mossy fiber-CA3 synapse Neuron. Author manuscript; available in PMC 2012 Sep 22. 

10. Majid Rostami Mogaddam, Nastaran Safavi Ardabili, Nasrollah Maleki, Maedeh Soflaee. Correlation between the Severity and Type of Acne Lesions with Serum Zinc Levels in Patients with Acne Vulgaris Biomed Res Int. 2014; 2014: 474108. 

11. Bae YS, Hill ND, Bibi Y, Dreiher J, Cohen AD. Innovative uses for zinc in dermatology. Dermatol Clin. 2010 Jul; 28 (3): 587-97.