The importance of zinc is often underestimated. It is no coincidence that over 80% of people lack this precious trace element. About 2 g of zinc is present in the human body; it is concentrated in the muscles, bones, prostate, eyes and skin, but can also be accumulated in the bones and spleen, where it is not readily available to be released when zinc is lacking. About 1% of the zinc present in the body is lost every day, mostly through the intestines and to a much lesser extent through sweat and urine. This precious mineral is involved in a large number of enzymatic processes and has an important role in growth, development and neurological function, with a great impact on growth and the immune response. Over 300 enzymes depend on the presence of zinc, including some involved in the synthesis of DNA and RNA, others that regulate growth and development processes, as well as others that regulate immune function or are involved in digestive and metabolic functions. One example of a very important enzyme containing zinc is carbonate dehydratase, which lets the body collect the carbon dioxide produced in tissues and eliminate it through the lungs. Its role is truly fundamental, considering how many activities it is involved in. Zinc also plays an important role in ensuring the integrity of structural proteins and membranes; a zinc deficiency would expose them to a higher risk of oxidative damage and thus reduce their functionality. Its “structural” role is linked to the fact that it is involved in the creation of “collagenases”, enzymes responsible for the formation of collagen and its elimination when damaged. In the “protein” field, it should be noted that proteins containing zinc are also involved in the regulation of genome transcription and cell signalling processes and influence the release of hormones, positively influencing insulin activity. Considering the countless activities in which its presence is requested, zinc is undoubtedly of great importance, but there are no real effective biological indicators to evaluate the element’s nutritional status. Generally its concentration in plasma or serum is evaluated, but these values are not very indicative because they are not sensitive to intense variations both throughout the day and due to inflammation, so the symptoms of a marginal zinc deficiency are not very clear and are often neglected. In children living in developing countries, for example, severe growth retardation and increased susceptibility to infections have been noted.
