Zinc - A True Precious Metal
The role of zinc in health is one that is becoming more and more widely understood, and we now realise how important a nutrient it really is. The mineral zinc is vital for Human health, and it is needed daily. Its roles are truly diverse and it has jobs to do in virtually every single body system. It has roles to play in the health of our immune system, in regulating hormones, influencing inflammation and much more.
Zinc in Immunity
Most likely one of the more well known roles that zinc plays in the body is a role in immunity. You only need to look on the shelves in your local health food store and you will see an array of zinc based supplements and remedies to target the common cold. Zinc lozenges for example. Whilst vitamin C has often been rather hit and miss when it comes to its performance in clinical trials for treating or aiding the common cold, zinc has been far more consistent. Many trials have shown that zinc can be very effective at shorten the duration and reducing the severity of the common cold.
The main reason behind this is that zinc has a regulatory role to play in the cells that make up the bulk of our immune system – the leukocytes or white blood cells. Zinc is actually used by the white blood cells to manufacture genes that are then used by the white cells to control the way in which they interact with pathogens and/or damaged and infected cells. Genes are the software that runs the hardware, and zinc is one of the programmers.
Zinc can also have an antiviral and antibacterial effect in its own right and can help to reduce bacteria and mucus build up in the nasal passages.
Zinc as an Antioxidant Co-Factor
Zinc has long been marketed as an antioxidant supplement, but this is slightly off the mark, but it IS important for reducing oxidative stress. It is a co factor for one of the body’s own in built antioxidant enzymes – Super Oxide Dismutase or SOD. This can help to reduce both oxidative stress that arises from day to day metabolism, through to localised immunologically driven inflammatory damage (Jarosz et al, 2017).
Zinc as a Hormonal Modulator
Another area that zinc is well known for is the influence that it has upon hormones. In men, zinc is vital for regulating the production of testosterone, and its effects appear to be a two way street. In adolescent males, where testosterone is pumping through the veins like a torrent, and causing all manner of issues such as mood fluctuations and acne, zinc can help to just curb things a little. Then, when men get over 40 their testosterone levels can begin to drop, leading to an array of issues such as – again, mood disorders and depression,. Loss of libido, weight gain and reduced lean muscle mass. In this scenario zinc can give testosterone a bit of a lift by increasing its production.
In women, zinc is necessary for the production of oestrogen and progesterone. Also, zinc will also help to curb excess androgen hormones in women. These androgen hormones such as testosterone do have important roles to play in women, but if allowed to get too high, they can cause fertility issues, PCOS and hirsutism amongst other issues.
The other hormone that zinc has an important impact upon is insulin. It appears that an adequate intake of zinc can increase the production of insulin in beta cells of the pancreas, and certainly animal studies have shown that zinc deficient diets have led to reduced beta cell insulin granules (Fukunaka & Fujitani 2018).
Zinc in Cardiovascular Disease
Zinc does appear to have an important protective role to play in cardiovascular disease. Firstly, as we saw earlier, it plays a role in the manufacture of Super Oxide Dismutase, the antioxidant enzyme that can prevent a certain amount of oxidative stress that can give rise to localised inflammation. When this happens within the endothelium (the skin that lines the insides of blood vessels) this can cause pockets of tissue damage that soon get occupied by lipids, white blood cells from the immune system, and develop into an atheroma or plaque. Preventing some of the inflammation early on can reduce the occurrence of these events.
Zinc also seems to play a role in managing hypertension aka elevated blood pressure. Again, this seems to be enzyme mediated with zinc being the enzyme cofactor.
Zinc in muscle growth and repair
Zinc is a vitally important nutrient for any athlete or anyone that engages in intense exercise. Zinc is important for muscle growth and repair. This is because it helps increase testosterone, growth hormone, and insulin like growth factor. These elements combined shorten workout recovery time and stimulate muscle growth.
Zinc and Mood
Zinc is a relatively new thing in terms of discussion around diet and mood, but it appears that zinc is involved in regulating many aspects of neurological function, from how signals in the brain are received, to how our brain and body responds to stress, and the one area in the body where zinc is most concentrated, is the brain.
It has been found that blood levels of zinc are very low in depressed patients. The more depressed the patient is, the lower their zinc levels.
The exact mechanisms here are not understood. It may prove to be the case that zinc partially has a role to play in the neurophysiology of depression, as well as being swallowed up by inflammation. Inflammation has been linked to depression, and zinc gets used up in large amounts in many of the biochemical pathways that manufacture proteins involved in the inflammatory response. So it is unclear at this point whether it is low intake of zinc that is contributing to the onset and development of depression, or whether inflammation is essentially burning it up and thats why blood levels appear low in patients with depression.
Zinc and Acne
Zinc is one of the most important nutrients for maintaining healthy skin. Firstly, it regulates the activity of the sebaceous glands. These are the glands in the skin that secrete oil to lubricate the skin. If the skin is too oily or too dry, adequate zinc intake appears to help the sebaceous glands adjust accordingly.
Secondly, as described above, zinc is vital for immune function. in issues such as acne, there is active infection which is causing the flare up. Supporting the immune system means that we are helping to reduce this active infection faster. The faster we can tackle the infection, the faster our skin clears and the lesions get better.
Best Food Sources of Zinc
The good news in all of this is that there are some everyday foods that are very rich in this vital mineral. Including my favourite – seafood. Here are the top contenders:
Milligrams Per 100g:
- Oysters – 78.6
- Beef – 12.3
- Pumpkin Seeds – 10.3
- Cashew Nuts – 5.6
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Fukunaka A, Fujitani Y. Role of zinc homeostasis in the Pathogenesis of Diabetes and Obesity. International Journal of Molecular Sciences. 2018 Feb; 19(2): 476.
Jarosz M, Olbert M, Wzszogrodzka G, Mlyniec K, Librowski T. Antioxidant and anti-inflammatory effects of zinc. Zinc dependent NF-kB signalling. Inflammopharmacology. 2017; 25(1): 11-24.