Zinc

Oral tracers of enriched ⁶⁷Zn and intravenously injected stable isotopic tracers with enriched ⁷⁰Zn are used simultaneously to determine the fraction of dietary zinc absorbed in humans, maintaining the amount or concentration of a nutrient or biomolecule in organs and body fluids. For example, zinc-isotope tracers can be administered to humans to determine if zinc absorption in their bodies may be impaired by ingestion of certain foods, food components, or dietary supplements. One such study conducted with Peruvian women showed that prenatal iron supplements affected the absorption of zinc during pregnancy. Another isotope tracer study investigated zinc deficiency in children with Crohn’s disease (an inflammatory disease of the intestines, especially the colon and ileum) [249], [250]. Zinc radioisotopes (e.g. ⁶⁵Zn, with a half-life of 244 days) can also be used for determining zinc absorption in humans, but they are now used rarely because of radiation hazards [251], [252]. ZnO nanoparticles enriched with ⁶⁷Zn have been used as biological/environmental nanotoxicity tracers [253].