Zinc is an essential mineral that is naturally present in some foods, added to others, and available as a dietary supplement. Zinc is involved in numerous aspects of cellular metabolism. It is required for the catalytic activity of approximately 100 enzymes and it plays a role in immune function, protein synthesis, wound healing, DNA synthesis, and cell division. Zinc also supports normal growth and development during pregnancy, childhood, and adolescence and is required for proper sense of taste and smell. A daily intake of zinc is required to maintain a steady state because the body has no specialized zinc storage system.
Sources of Zinc
Oysters contain more zinc per serving than any other food, but red meat and poultry provide the majority of zinc in the Western diet. Other good food sources include beans, nuts, certain types of seafood (such as crab and lobster), whole grains, and dairy products. Phytates bind zinc and inhibit its absorption which is commonly found in whole-grain breads, cereals, legumes, and other foods. Thus, 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
People with gastrointestinal and other diseases
Gastrointestinal surgery and digestive disorders (such as ulcerative colitis, Crohn’s disease, and short bowel syndrome) can decrease zinc absorption. Other diseases associated with zinc deficiency include malabsorption syndrome, chronic liver disease, chronic renal disease, sickle cell disease, diabetes, malignancy, and other chronic illnesses. Chronic diarrhea also leads to excessive loss of zinc.
Vegetarians
The bioavailability of zinc from vegetarian diets is lower than from non-vegetarian diets because vegetarians do not eat meat, which is high in bioavailable zinc and may enhance zinc absorption. In addition, vegetarians typically eat high levels of legumes and whole grains, which contain phytates that bind zinc and inhibit its absorption. To increase zinc bioavailability, include soaking beans, grains, and seeds in water for sev- eral hours before cooking them and allowing them to sit after soaking until sprouts form.