Spotlight on Zinc

Zinc is a relatively young mineral compared to other nutrients. Its discovery for human health was made in 1961 and it was only in 1974 that the National Research Council of the National Academy of Sciences declared zinc an essential mineral for human nutrition (1).

Zinc is an essential trace element and one of the most abundant elements in our cells. There is approximately 2g of zinc in our body with 60% found in our skeletal muscle and 30% in our bones. It is crucial for human health as it is vital for the proper functioning of the body. Zinc is needed for over 300 different enzymes to enable them to perform their important chemical reactions in the body. Its actions in the body can be broken up into three categories:

1. catalytic
2. structural
3. regulatory

So what does zinc actually do in the body? Well let’s find out!

Zinc’s key bodily functions

• Immune Health – Zinc has a crucial role to play in our immune health and keeping our immune system functioning at its best. It is involved in the proper development and function of our immune cells and helps regulate the immune system. A deficiency in zinc can adversely impact the immune system, causing impaired immune function.

• Skin health – Zinc is essential for the health of our skin. Did you know that approximately 6% of the zinc found in our body is located in the skin? (4) Zinc is vital for wound healing, tissue regeneration, oil gland function, connective tissue formation and protein synthesis (8, 9). Having a zinc deficiency can significantly delay the healing of a wound. (9) It has also been found that people suffering from mild eczema, mild psoriasis and mild dermatitis tend to have lower zinc levels as well (1,2,8,9).

• Acne - It has also been shown that people suffering from acne tend to have lower zinc levels (5,6,7, 9). It has been revealed that the severity of acne can be linked with the serum blood and or plasma zinc level in the individual (1, 7). It is believed that the way zinc assists acne is via its anti-inflammatory effect and influence on vitamin A and androgen metabolism (7). There have been great results in people with acne when using zinc. Improvements have been seen in their skin condition when using either internal zinc supplementation and or a topical zinc preparation, on their own or in combination with other treatments. (1,2,6,9).

• Prostate Health – Did you know that the prostate gland contains a high concentration of zinc? The prostate and testes actually contain the highest levels of zinc compared to any other organ in a man’s body! Zinc is an essential men’s health mineral. It supports the health of the prostate gland and helps inhibit 5-alpha reductase activity. This is important in men who are suffering from Benign Prostatic Hyperplasia (BPH). Did you know that as men age, their zinc levels decrease in the prostate and the prostatic fluid? This drop in zinc can impact and influence men’s fertility. Zinc’s antioxidant properties also play a very important role in the protecting the prostate from free radical damage. Also, did you know that a man loses approximately 1mg of zinc each time he ejaculates? So it is extremely important men ensure they are getting enough zinc daily.

• Sexual health & Fertility – Zinc is crucial for sexual development and maturation in both males and females and is necessary for ovulation, sperm health, fertilisation and implantation. Zinc deficiency can lead to delayed sexual maturation and hypogonadism. In men, zinc is vital for healthy sperm, it is needed for sperm motility, morphology (shape, form, structure) and healthy sperm levels / volume / count. It has been shown that zinc protects sperm against free radical damage and zinc is needed for testosterone production. If there is a zinc deficiency, this can impact the production, development and maturation of sperm and change sperm morphology. In women, zinc is needed for the metabolism of progesterone and oestrogen and is essential for ovulation and pregnancy.

• Pregnancy & Breastfeeding – It is very important to have adequate zinc levels during pregnancy. Zinc helps contribute to a healthy pregnancy as it is essential for the formation and development of an embryo and contributes to healthy foetal growth and development. A deficiency in zinc or low maternal zinc status, can seriously impact pregnancy outcomes. Adequate levels of zinc are also important to maintain during breastfeeding, as zinc is necessary for the healthy functioning of the mammary gland. So it is crucial to maintain healthy zinc levels during preconception, pregnancy and breastfeeding.

• Antioxidant – Zinc has a fundamental role in protecting the body from free radical damage. It does this in multiple ways including:

1. Playing a crucial structural role in the antioxidant superoxide dismutase (SOD), a vital antioxidant in our body that has an essential role in the defense against oxidative stress (free radical damage).

2. Controlling the release of vitamin A.

3. Protects against the depletion of vitamin E.

4. Supresses the creation of internal free radicals.

5. Controlling the body’s concentration of metallothionein (MT), which is important for zinc homeostasis. Metallothionein can donate zinc ions to other proteins and it may also reduce free radical damage in cells that are under high stress.

Could you be deficient in Zinc?

An inadequate intake of zinc and borderline zinc deficiency is actually quite common. However, severe zinc deficiency is rare in developed countries. If zinc deficiency was to occur, signs and symptoms can happen and happen quickly, especially if the dietary zinc intake is low. In children who are still growing, zinc deficiency signs and symptoms can start to show in a few days. Where as in adults, signs and symptoms of zinc deficiency can develop within a few weeks. But don’t worry, low level zinc deficiency can be rectified relatively quickly once zinc intake is increased.

Some of the most common symptoms of zinc deficiency include:

• Reduced sense of smell and taste
• Poor wound healing
• Lowered immune system function
• Delayed growth and development
• Slow sexual maturation
• Dermatitis
• Low appetite
• Mental fatigue
• Hair loss

People at risk of zinc deficiency:

• Strict vegetarians
• The elderly
• People consuming high phytate diets
• People under high stress

If you are concerned about your zinc levels, speak to your doctor to have your levels checked. 

How much zinc should I be having?

The recommended daily dietary intake of zinc is as follows:

What foods contain zinc?

Zinc is found in high concentrations in meat, poultry, fish and animal foods including liver, eggs, oysters and shellfish. Non animal sources include mushrooms, brewer’s yeast, green beans, miso and tofu. Zinc is also found in nuts, seeds, legumes and wholegrains but it is hard to absorb due to the phytate content. However, to help the bioavailability and absorption of zinc from those sources, sprouting or fermenting these foods where appropriate, helps reduce the phytate content in these foods.

So now you know a little more about this marvellous mineral!

References

1. Braun, L. & Cohen, M. 2015. Herbs & Natural Supplements An evidence-based guide, volume 2, 4^th edition. Zinc (chapter). Churchill Livingstone Elsevier. Sydney. Pp 1197 – 1223

2. Global Information Hun On Integrated Medicine (Globinmed). Zinc (Dietary Supplement (Professional)). Accessed from http://www.globinmed.com/index.php?option=com_content&view=article&id=78264:zinc-78264&catid=18&Itemid=101 on 29.3.19

3. Linus Pauling Institute – Micronutrient Information Centre. 2013. Zinc monograph. Accessed from https://lpi.oregonstate.edu/mic/minerals/zinc on 29.3.19

4. Linus Pauling Institute Micronutrient Information Center. Minerals and Skin Health. Accessed from http://lpi.oregonstate.edu/mic/health-disease/skin-health/minerals

5. Cervantes, J. et al. The role of zinc in the treatment of acne: A review of the literature. Wiley Dermatologic therapy. 2007. Pp: 7-17

6. Butool, F., Rekha, C. & Gnaneswar Rao. Clinical Study on Serum Zinc Levels in Patients with Acne Vulgaris. Asian J. Research Chem. 6(5): May 2013; Page 464-466

7. Amer, M. et al. Serum Zinc in Acne Vulgaris. International Journal of Dermatology. 1982 Vol. 21. Pp 481 – 484

8. Reavley N. Encyclopedia vitamins, minerals, supplements, & herbs. M. Evans. Lanham. Pp 310 – 324

9. Murray, M. Encyclopedia of nutritional supplements. Three Rivers Press. New York. Pp 181 – 189

10. Younus, H. Therapeutic potentials of superoxide dismutase. Int J Health Sci (Qassim). 2018 May-Jun; 12(3): 88-93

11. Zhao J, Dong X, Hu X, et al. Zinc levels in seminal plasma and their correlation with male infertility: A systematic review and meta-analysis. Scientific Reports. 2016;6:22386. doi:10.1038/srep22386.

12. Foresta C., et al. Role of zinc trafficking in male fertility: from germ to sperm. Human Reproduction, Vol.29, No.6 pp. 1134-1145,2014