Zinc is one of the more common deficient nutrients in the developed world. The reasons for this vary. Everything from poor soil quality, through to restricted diets or diets heavily reliant on processed foods have been blamed for this. Whatever the reason, it is important that you are aware of how vital this nutrient is for our health, and how easy it is to get enough.
Immunity and wound healing
In the many trials that have studied nutrition and immune function, especially in the context of fighting things like the common cold, the outcomes have been mixed to say the least. Vitamin C for example has a really mixed performance for reducing the duration of a common cold and is the subject of much debate. however, one nutrient has consistently performed well in trials. Zinc!
Zinc has many roles to play in immunity. It is crucial for the development and function of Neutrophils and Natural Killer cells (both are types of white blood cell in the immune system). It is also used by white blood cells to code genes that regulate the way in which they respond to pathogens - ie regulating the release of cytokines, or how white cells can instigate programmed death of infected cells etc.
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.
Keeps hormones in Check
Zinc plays a vital role in the regulation of many hormones. It is involved in the production and regulation of testosterone. In men, testosterone keeps us young and vigorous, helps maintain muscle mass, keeps us lean, and is important for fertility, to name but a few things. Much of the change that happens in middle age and beyond is due to testosterone levels dropping, so keeping it high is a must. Testosterone isn't just a male hormone. Women have it too and it is needed for the creation and release of eggs from the ovaries, the production of oestrogen, and of progesterone.
It also goes as far as influencing, to some degree at least, metabolic hormones such as insulin.
Influences on 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.
It is used by over 300 different enzymes in the body
Enzymes are essentially facilitators in the body. They are the biochemical agents that allow things to happen at an accelerated rate. They speed up different pathways that make things, release things, regulate things. They can be thought of as the green light for these processes taking place. Zinc is used by over 300 of these enzymes, so you can see that if we don't have enough to go around, then we can get into trouble.
So….what are the best dietary sources?
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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