Iron: Part of hemoglobin found in red blood cells that carries oxygen in the body; needed for energy metabolism
Food sources of iron: Organ meats; red meats; fish; poultry; shellfish (especially clams); egg yolks; legumes; dried fruits; dark, leafy greens; iron-enriched breads and cereals; and fortified cereals

Zinc: Part of many enzymes; needed for making protein and genetic material; has a function in taste perception, wound healing, normal fetal development, production of sperm, normal growth and sexual maturation, immune system health
Food sources of zinc: Meats, fish, poultry, leavened whole grains, vegetables

Iodine: Makes up thyroid hormone which helps regulate growth, development, and metabolism
Food sources of iodine: Seafood, foods grown in iodine-rich soil, iodized salt, bread, dairy products

Selenium: Antioxidant for cellular health
Food sources of selenium: Brazil nuts, oysters and some other seafood, meats, grains, brewer's yeast

Copper: Part of many enzymes; needed for iron metabolism
Food sources of copper: Legumes, nuts and seeds, whole grains, organ meats, drinking water from copper pipes

Chromium: Works closely with insulin to regulate blood sugar (glucose) levels
Food sources of chromium: Unrefined foods, especially liver, brewer's yeast, whole grains, nuts, cheeses

Molybdenum: Part of some enzymes
Food sources of molybdenum: Legumes; breads and grains; leafy greens; leafy, green vegetables; milk; liver

Manganese: Part of many enzymes
Food sources of manganese: Widespread in foods, especially plant foods

Other trace nutrients known to be essential in tiny amounts include silicon, vanadium, and cobalt.