The adult RDA for zinc is 15 milligrams per day for males, and 12 mg per day for females. Individual adult requirements vary depending on your age, activity level, and foods that you eat. For example, competitive athletes can lose more than one mg of zinc through their sweat per day, which increases their zinc requirements. After puberty, the requirement is the same as the adult requirement. Although the RDA for someone 63 years old is the same as for younger adults, many adults eat less zinc-rich foods as they get older, and their ability to absorb the zinc they do eat decreases.
Zinc deficiency is most common in older people.
It is even more difficult for children and adults to get enough zinc if they are on vegetarian diets, since these diets do not contain zinc-rich foods, which include lean red meats, poultry, and certain seafood, such as oysters. There are fortified cereals, certain vegetable foods, such as wild rice, wheat germ, pumpkin seeds, and some nuts, such as pecans and Brazil nuts, which contain zinc. However, the zinc in these foods is not as easily and completely absorbed as the zinc in animal foods.