Zinc is a trace mineral that is essential for many bodily processes as your body can’t produce or store it, therefore it must be acquired through the diet via the food you eat.
Zinc assists in processes throughout the body such as DNA synthesis, enzymatic reactions, immune function, protein synthesis, wound healing. Zinc is necessary for the activity of over 300 enzymes that aid in metabolism, digestion, nerve function and many other processes and is the second-most abundant trace mineral in the body (behind iron). It also supports normal growth and development during pregnancy, childhood, and adolescence and is required for proper sense of taste and smell.
A wide variety of foods contain zinc and oysters contain more zinc per serving than any other food, but red meat and poultry provide the majority of zinc in a standard diet. Other good food sources include beans, nuts, certain types of seafood (such as crab, prawns or crayfish), whole grains, fortified breakfast cereals, and dairy products.
Phytates, which are present in whole-grain breads, cereals, legumes, and other foods, bind zinc and inhibit its absorption. Therefore, the bioavailability of zinc from grains and plant foods is lower than that from animal foods, although many grain- and plant-based foods are still good sources of zinc, especially for individuals who don’t have animal foods as part of their diet.
Zinc deficiency is characterised by growth retardation, loss of appetite, and impaired immune function. In more severe cases, a zinc deficiency causes hair loss, diarrhoea, delayed sexual maturation, impotence, hypogonadism in males, and eye and skin lesions. Weight loss, delayed healing of wounds, taste abnormalities, and mental lethargy can also occur when zinc levels are low.
Zinc toxicity can occur when there has been high zinc intake and symptoms include nausea, vomiting, loss of appetite, abdominal cramps, diarrhoea and headaches. The recommended daily intakes differ across life stage, but for adult males 19+ its 11mg/day and adult females 19+ its 8mg/day. This increases for pregnant and breastfeeding women to 11mg/day and 12mg/day, respectively.