Zinc is more important than we may realise
Zinc was not something I gave much thought to as a young adult until as a Chemistry student I to attended a lecture by Professor Derek Bryce-Smith. The topic was the importance of zinc in the diet. Professor Bryce Smith was convinced that the use of artificial fertilisers in agriculture were responsible for the growing numbers of people with zinc deficiency. Vegetarians were particularly vulnerable to zinc deficiency.
Professor Bryce-Smith used his guest lecture to introduce us to a product he had just started selling through health food shops. Essentially his product was simply a very dilute zinc sulphate solution. If drinking it was just like a nice sip of water then this indicated zinc deficiency. Because zinc is toxic at levels just above those required by the body; if there is enough zinc in the body, the product tastes foul.
I was a committed vegetarian at the time, I might even have been vegan and that liquid was delicious. All around me, people were pulling faces and yucking loudly. I did the same, pretending that it was the most disgusting stuff I had ever eaten. It was a moment I have never forgotten. Over the years since then I have prepared the occasional, very dilute solution of zinc sulphate and tasted it.
(By the way, don’t try that in your own local chemistry lab – bench chemicals are NOT suitable for human consumption!)
Every time the solution was completely tasteless. Until a couple of weeks ago when a couple of horrified technicians watched me gag. Not only was the solution disgusting but the aftertaste lasted for hours. Having given up eating grains and reduced the amount of phytic acid in my system meant that I was no longer deficient in zinc. Phytic acid is one of the antinutrients in grains and it prevents the body absorbing a number of different minerals.
We only need a tiny amount of zinc in our body, too much is toxic but it is essential for health and well being. Our immune systems depend on it. It is necessary for cell maintenance and development and a lack of it can cause skin problems such as acne and boils. People with psoriasis are advised to take zinc supplements and those white spots on the fingernails signal a lack of zinc.
Deficiency is also characterised by allergies, night blindness (my vegan friend suffered with this) loss of sense of smell, loss of sex drive, loss of hair, sleep problems and frequent infections.
Adequate levels of zinc are needed for good fertility in both sexes and it is particularly important for men as zinc is lost from the body everytime they ejaculate.
Oysters are famously a particularly good source of zinc but most people rely on other shellfish, meat, grains, eggs, nuts, seeds and brewers yeast to get their daily dose. Grains are not a good source of zinc because their phytic acid content which makes it inaccessible to the body.
Professor Bryce-Smith died in 2011 at the age of 85. He was one of the first chemists to identify tetra ethyl lead, widely used as an anti knocking additive in petrol as toxic and worked hard to spread knowledge on zinc deficiency.