Dietary sources of iron

High levels of iron can come from taking iron supplements or eating too much of foods rich in iron, like red meat. Food contains two types of iron: heme iron and nonheme iron. Heme iron is derived from hemoglobin, the protein in red blood cells that delivers oxygen to cells. Heme iron is found in animal foods that originally contained hemoglobin, such as red meats, fish, and poultry. Iron in plant foods such as lentils and beans is arranged in a chemical structure called nonheme iron. Nonheme iron is absorbed better when it is consumed with animal protein and with vitamin C. Heme iron is absorbed much better than nonheme iron.

The best dietary sources of iron are liver and other organ meats, lean red meat, poultry, fish, and shellfish (particularly oysters). Iron from these sources is readily absorbed in the intestines. Other sources of iron include dried beans and peas, legumes, nuts and seeds, whole grains, dark molasses, and green leafy vegetables. Ferrous sulfate is the most common type of iron supplement. Other available forms include ferrous fumarate, ferrous succinate, ferrous gluconate, ferrous lactate, ferrous glutamate, and ferrous glycine.