Zinc is an essential mineral of exceptional biologic health importance. Zinc is directly related to over 50 body functions including taste, smell, vision, sexual development, digestive enzyme production, blood sugar regulation, male potency, prostate gland health and the processing of alcohol.
There are between 2 and 4 grams of zinc distributed throughout the human body. Most zinc is in the brain, muscle, bones, kidney, and liver, with the highest concentrations in the prostate and parts of the eye. It is a key factor in proper prostate function and reproductive organ growth.
Zinc reacts with a great number of organic molecules in the body: it has been estimated that about 10% of human proteins potentially bind zinc, in addition to hundreds more which transport and traffic zinc. It also plays a role in the metabolism of DNA, RNA and gene expression.
In the brain, zinc is known to modulate brain excitability, and plays a key role in synaptic plasticity (and thus in the ability to learn).
Refined food is low in zinc, however good sources are herring, oysters, clams, wheat bran, oatmeal, liver, red meats (especially beef, lamb and liver) and chicken thighs. Vegetarians run a high risk of zinc deficiency as the concentration of zinc in plants varies based on levels of the element in soil. When there is adequate zinc in the soil, the food plants that contain the most zinc are wheat (germ and bran) and various seeds (sesame, poppy, alfalfa, celery, mustard). Zinc is also found in beans, nuts, almonds, whole grains, pumpkin seeds, sunflower seeds and blackcurrant.
Groups at risk for zinc deficiency include the elderly, vegetarians, and those with renal insufficiency – and diagnosing zinc deficiency is a persistent challenge.
Zinc deficiency is usually due to insufficient dietary intake – which can be the result of an excessive reliance on refined or ‘fast foods’ – but can be associated with malabsorption, liver disease, renal disease, sickle cell disease, diabetes, and malignancy. Symptoms of even mild zinc deficiency are diverse – including depressed growth, diarrhea, impotence and delayed sexual maturation, alopecia, eye and skin lesions, impaired appetite, altered cognition, impaired host defense properties, defects in carbohydrate utilization, and reproductive teratogenesis. Mild zinc deficiency depresses immunity, although the same can be true of excessive zinc intake. Zinc also helps prevent diabetes, acne, epilepsy and childhood hyperactivity and helps detoxify toxic metals.
Zinc deficiency affects about two billion people worldwide and contributes to the death of about 800,000 children worldwide per year.