Zinc

- Trace elements that exist in all tissues of in the human body

- Functional effect: Element essential for normal immune function and normal cell division

- Daily intake: 2.55~12mg (Source: Korea Food & Drug Administration)

What is zinc?

Zinc is a trace element that exists in all tissues of in the human body, which is essential for normal immune function and cell division process.

The total amount of zinc in the human body is about 1.58~2.5g, of which 90% exists in muscles and endoskeletons, performing basic biochemical role.

Infants require higher amount of zinc because of their fast development, and the age group must take the sufficient amount through food or supplement.

The best source of supply of zinc includes oyster, meat, poultry, clam, egg and dairy product.

Zinc is contained in vegetable food such as peanuts, beans and grains. However, zinc contained in grains that exist mainly in the skin, which means it would be easily lost during the polishing process.

Besides, a variety of animal/vegetable food contains zinc. However, zinc contained in animal food is well absorbed than that in vegetable food.

ㅣOyster, source of supply of zinc

Effect of zinc

1. Involves the regulation of main metabolism or response

Zinc has the structural element composed of over 200 types of effects, participating in many biological responses in the living body.

2. Essential element for normal cell division, influencing on the growth and development
Zinc is essential for effects that influence on cell division and proliferation. DNA synthesis is regulated through this system, growth is influenced by the regulated hormone during the cell division process.
Lack of zinc would inhibit the proper growth and development with the synthesis of collagen and DNA.

3. Performs important role for immune system

Zinc raises the activation of immune system cells including T lymph cell, natural killer cell, and interleukin.
To the contrary, the lack of zinc declines the function of natural killer cells, which lead to the reduction in edacious activity and antibody production of macrophage cells and result in the great decline in immune function. 

Therefore, the lack of zinc would lead to frequently catch cold or suffer from infection.

4. Helps prevent the prostate gland related diseases
Zinc is essential for the production of malehormone, named testosterone, reducing the cases where testosterone is transformed into dihydrotestosterone (DHT) that proliferates prostate gland, thereby protecting prostatism against prostatism.
In the human body, zinc is most distributed in prostate gland, zinc content in semen is as much as 100 times higher than that in blood content.

5. Improves male infertility and effective in promoting the formation of semen
 Zinc generates/recovers DNA and forms the antioxidant defense mechanism. 
 When deficient in zinc, semen sensitive oxidative damage can be deteriorated in quality and production.

6. Required for Omega-6 oil to be transformed to Gamma Linolenic acid 
 Gamma Linolenic acid produces hormone that inhibits inflammation.
 The lack of zinc leads to inflammation and worsen the atopic dermatitis cases.

7. Required for vitamin A effect
 The lack of either zinc or vitamin A results in the lack of the other. 
 Losing eye sight, amblyopia and yellow spot degeneration may occur due to the lack of zinc.

8. As zinc exists in all tissues, zinc-deficiency may make influence on the whole body

Zinc-deficiency may cause loss of taste/ smell and impaired hearing, prostatic disease, hypogonad, infection, amblyopia, night blindness, white spot nail and amyotrophia. The zinc content in our body is reduced with ages. 

In addition, deficiency of zinc is common among the alcoholics, vegetarians, and patients with kidney disease or liver disorder.
 As zinc is necessary to generate insulinand thyroxine, the zinc-deficiency may lead to diabetes or hypothyroidism.

Related Articles

1. Iron and zinc supplement therapy performed in the clinic (Gi-young Cho, SahmYook Medical Center for Youth and Pediatr Gastroenterol Hepatol Nutr 2012; 15(Suppl 1): S7~S16) 

: Zinc is essential and important element for children’s growth and development. The lack of zinc is associated with the decline in various biochemical functions. Zinc is effective in treatment and prevention of children’s diarrhea and acute lower respiratory infection.

2. Zinc gluconate in the treatment of dysgeusia – a randomized clinical trial (Heckmann SM, Hujoel P, et al., J Dent Res. 2005 Jan;84(1):35-8) 

: Clinical trial indicates that zinc is effective element for the treatment of dysgeusia, when there was the increase in dysgeusia in patients with regular intake of zinc that resulted in depression improvement.

3. Light-induced retinal degeneration is prevented by zinc, a component in the age-related eye disease study formulation (Orgenisciak D, et al., Photochem Potobiol. 2012 Nov-Dec;88(6):1396-407)

: Zinc raises retinal antioxidation activity, reducing oxidative loss when retina is exposed to light.

4. Zinc deficiency in women, infants and children.  (Sandstead HH, J Am Coll Nutr. 1996;15:113-120)

5. Controlled trial of zinc supplementation during recovery from malnutrition: effects on growth and immune function. (Castillo-Duran C, et al., Am J Clin Nutr. 1987 Mar;45(3):602-8) 

6. Zinc supplementation decreases incidence of infections in the elderly: effect of zinc on generation of cytokines and oxidative stress. (Prasad AS, Beck FW, Bao B, et al. Am J Clin Nutr. 2007;85:837-844.)

7. Zinc gluconate and the common cold. Review of randomized controlled trials. (Marshall S. Can Fam Physician. 1998;44:1037-1042.)

8. Meta-analysis: zinc supplementation for acute gastroenteritis in children. (Patro B, Golicki D, Szajewska H. Aliment Pharmacol Ther. 2008 Jul 1.) 

9. The effect of zinc on the 5 alpha-reduction of testosterone by the hyperplastic human prostate gland. (Leake A, Chisholm GD, Habib FK. J Steroid Biochem. 1984;20:651-655.)

10. Effect of zinc administration on plasma testosterone, dihydrotestosterone, and sperm count. (Netter A, Hartoma R, Nahoul K. Arch Androl. 1981;7:69-73.) 

11. A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss (Age-Related Eye Disease Study Research Group. AREDS Report no.8. Arch Ophthalmol. 2001;119:1417-1436.)