If you need to get more iron, there are many foods that you can eat to meet your needs. According to the Office of Dietary Supplements, iron comes in two forms: heme and non-heme. Heme iron is found in animal products, such as meat, poultry and fish. Fortified or enriched cereals and grains, legumes and spinach are good sources of non-heme iron, which is found in plant foods.
Iron Functions
Iron is a mineral that functions primarily as a carrier of oxygen in the body--as part of hemoglobin in the blood and myoglobin in the muscles. Iron is also a component of numerous enzymes and is essential for regulation of cell growth and differentiation.
Iron Requirements
The recommended daily allowance for iron is 8 mg for men, 18 mg for women aged 19 to 50, 8 mg for women aged 50 and older, 27 mg during pregnancy and 9 mg during lactation, according to the Institute of Medicine. The RDA or daily value used as a reference on food labels is 18 mg, according to the FDA.
Iron Deficiency
A deficiency of iron limits oxygen delivery to cells, causing fatigue and weakness, poor work performance and decreased immunity, which increases susceptibility to infection. Other symptoms include difficulty maintaining body temperature and glossitis, or inflamed tongue. Iron deficiency is usually caused by low dietary intake of iron, inadequate absorption of iron or excessive blood loss. Other causes include kidney failure, vitamin A deficiency and chronic malabsorption from a gastrointestinal disorder, such as Celiac disease or Crohn's syndrome.
Iron Sources
A 3/4- to 1-cup serving of many fortified cereals provides 100 percent DV for iron, according to the USDA National Nutrient Database. One cup of enriched farina contains 72 percent to 96 percent and a packet of fortified instant oatmeal has 58 percent DV. One cup turkey or chicken giblets provides 61 and 56 percent, respectively. Legumes are also a good source of iron, with 1 cup of baked beans, white beans, lentils, kidney beans, chickpeas, green soybeans, lima beans, black-eyed peas, navy beans, green peas, black beans or pinto beans providing 20 to 45 percent DV. One cup enriched white rice contains 44 percent DV, 1 cup of cooked spinach contains 36 percent, 3 oz. of oysters contains 33 percent and 3 oz. of beef liver contains 29 percent.
Additional foods that provide 10% to 19% DV include: 1 c. stewed tomatoes, cooked turnip greens, beets, prune juice, split peas, tomato sauce, roasted turkey, sweet potato, collards, canned plums, barley, tuna salad, stewed chicken, cooked Brussels sprouts or enriched pasta; 3 oz. beef chuck or round, sardines, clams, ground beef---85% lean or higher, roasted turkey or shrimp; 5 oz. canned chicken; or a baked potato with skin.
Iron Absorption
The body absorbs heme iron, which comes from animal sources, much more efficiently than non-heme iron, which comes from plant sources. Meat proteins and vitamin C improve the absorption of non-heme iron. The IOM explains that the RDA assumes 75 percent of iron intake is from heme iron sources. Non-heme absorption is lower for those consuming a vegetarian diet than for those eating nonvegetarian diets. Therefore, the iron requirement for vegetarians is about two times greater than for those consuming a nonvegetarian diet.
Including a vitamin C-rich food--such as citrus fruits, strawberries, red and green bell peppers, broccoli or tomatoes--will increase absorption of non-heme iron. For example, drink a glass of orange juice along with a bowl of fortified cereal. In contrast, other food components are known to decrease iron absorption, such as tannins found in tea, calcium, polyphenols and phytates found in legumes and whole grains.
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