Dietary Zn—Recent Advances in Studies on Its Bioaccessibility and Bioavailability

Zn is a trace element necessary for the functioning of about 300 enzymes. It plays a biochemical, structural, and regulatory role. It participates in the immune response, proper functioning of the endocrine system, and regulation of gene expression. Its deficiencies are most often caused by the mismatch between dietary intake and the body’s needs. Bioavailability of zinc depends on interactions with other food components. Phytates negatively affect this element’s absorption, whereas proteins, peptides, and amino acids increase its bioavailability. It has been proven that organic forms of zinc are better absorbed than inorganic compounds, like zinc oxide and sulfate. Amino acid combinations with zinc can use amino acid transporters in the absorption process. Estimation of Zn bioavailability and bioaccessibility are based on in vivo and in vitro studies, each having their advantages and disadvantages. The current review aims to gather and summarize recent research on the dietary role of Zn, especially data on bioavailability from food substances promoting/inhibiting absorption, and the latest methods for determining the level of bioavailability of this nutrient.