Sources of iron

Originally Published: October 27, 1995 - Last Updated / Reviewed On: March 4, 2014
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Dear Alice,

What are the major sources of iron (especially vegetables, if any)? Thank you.

— Popeye

Dear Popeye,

You can definitely find iron in foods other than spinach, that's for sure! Animal sources of iron include liver, kidneys, red meat, poultry, fish (especially oysters and clams), and eggs. Good plant sources of iron include peas, beans, nuts, dried fruits, leafy green vegetables (especially spinach), enriched pastas and breads, and fortified cereals. Our ability to absorb iron from foods varies from about three percent to 40 percent, depending on its form in the food, the body's need for it, and a variety of other factors. Iron from animal proteins (heme iron) is better absorbed by the body than iron from plant foods (non-heme iron).

Iron is an essential mineral our body needs to function well. Iron is necessary for the formation of hemoglobin, which carries oxygen in the blood, and myoglobin, which carries oxygen in muscle. It is part of several enzymes and proteins in the body, is needed for immune function, and contributes to drug detoxification pathways in the liver.

Certain foods and nutrients can impact how much iron you get from your food: zinc, high-dose calcium supplements, and tannins in tea can all reduce iron absorption. Compounds known as phylates and oxalates, found in grains and vegetables, respectively, can all bind iron and therefore reduce its absorption as well. To optimize the amount of iron you get from plant foods, eat them with a food high in vitamin C at the same meal. Foods high in vitamin C include broccoli, tomatoes, greens, sweet potatoes, white potatoes, cantaloupe and citrus fruits. You can also eat meat or other food with heme iron along with plant foods to enhance the absorption of all nonheme iron present.

The recommended daily allowance (RDA) for iron is 8 mg for adult men (ages 19-50+) and 18 mg for adult women (ages 19-50). The higher dosage for women in this age range is primarily because of menstrual blood loss. After the age of 50, a woman's RDA is 8 mg. If you don't take in enough iron, you can become iron-deficient. Iron deficiency is one of the most common nutrient deficiencies internationally, and is most common when iron needs are greatest in your life cycle — during infancy, preschool years, and puberty, and during child-bearing years for women. Pregnancy and disease also increase iron needs. For more information, see Iron deficiency in the General Health archive. If you are at Columbia, contact Medical Services (Morningside) or the Student Health Service (CUMC) to make an appointment with a health care provider and/or a nutritionist, who can discuss your dietary needs and iron intake.

Alice