Zinc is a metallic element (atomic number 30) that the body uses as a micronutrient. In plants and animals, it plays a key role in many enzymes, as well as being important in the metabolism of DNA and RNA. It also plays a role in some proteins. Most foods contain some zinc, and the amount of zinc in plants is generally determined by the amount of zinc in the soil. Wheat and seeds tend to be higher in zinc than other plants.
Zinc toxicity can result from exposure to too much of the metal. Too much zinc prevents the body from properly using copper and iron. In can be the result of swallowing pennies (which are almost all zinc and dissolve quickly in stomach acid) or the use of denture adhesive, which is rich in zinc oxide.