Zinc

Zinc is, after iron, the most abundant trace element in your body, and it is everywhere. Hundreds of enzymes need it, and thousands of proteins that read your DNA use zinc as a clamp. So a deficiency affects everything that divides and repairs quickly: your immune cells, your skin and hair, the lining of your gut, your taste and smell buds, and the cells in the testicles that make testosterone. Zinc is in oysters and other shellfish, meat, cheese, eggs, pumpkin seeds, legumes and whole grains; from plant sources you absorb it less well, because the fibres bind it. Your body has no real store of zinc. What you do not take in, you miss within weeks, and that is why the supply counts continuously. The value in your blood is moreover only a fraction of all your zinc, and that fraction travels largely bound to albumin. If albumin falls, the zinc value falls with it without you having less zinc. With an inflammation the body also pulls zinc temporarily out of the blood into the liver, and after a meal the value dips a little too. Your report shows zinc in µmol/L, and normal is about 11 to 18 µmol/L where the labs overlap. It is drawn in the morning, fasting, in a special tube free of metal traces, and the tube must not haemolyse, because your red blood cells are full of zinc.

Zinc is one of the deficiencies you see on the outside before you measure it: slower-healing cuts, more frequent colds, skin complaints, hair loss, brittle nails, less taste and smell, and in men a lower testosterone and less desire. None of those symptoms is proof on its own, but together they point at the supply, and a zinc value turns that suspicion into a number. The groups in which the supply falls short are clear. Anyone who eats plant-based gets zinc from sources it is poorly absorbed from, because the fibres in grains and legumes bind it; soaking, sprouting and fermenting help with that. Anyone who drinks a lot passes more zinc in the urine and often eats less. Anyone pregnant or breastfeeding needs more. And anyone who absorbs poorly, after stomach surgery, with coeliac disease or a chronic gut inflammation, or with prolonged diarrhoea, loses zinc faster than it comes in. Older people often combine a few of these. The other side exists too. Zinc is a popular supplement, against colds, for the skin and for testosterone, and months of a high dose push copper out of the uptake. That gives a copper deficiency with anaemia and nerve symptoms, and that is an unhappy result of a well-meant jar. A zinc value beside a copper value shows whether the balance still holds.

A low zinc means too little supply, too much loss, a low albumin or an inflammation. Usually it is the first and rarely the last: one-sided or plant-based eating, a low albumin, alcohol, poor absorption in the gut, an inflammation, and rarely chronic kidney disease or an inherited absorption disorder. Look first at albumin and CRP: if albumin is low or CRP high, the low zinc value is a consequence of that and says little about your supply. If those two are fine, a low zinc is a real deficiency, and then diet and a supplement help within weeks. A high zinc is usually a supplement taken shortly before the draw, or a tube that has haemolysed or sat too long under the tourniquet. Too much zinc from food does not occur. The harm of too much zinc does not sit in the zinc value itself, but in the copper it pushes out. Zinc belongs beside albumin and CRP, and beyond that beside copper, and in men with symptoms beside testosterone. Have blood drawn in the morning, fasting, and compare over time at the same lab.