Iron plays an essential role in cell growth and the delivery of oxygen to the body's organs and tissues. Iron absorbed in the intestinal tract goes toward the production of hemoglobin, a protein in red blood cells responsible for oxygen transport, and myoglobin, a protein that delivers oxygen to muscles. A variety of food components can hinder absorption of iron from plant-based sources.
Types of Iron
Animal-based foods that originally contained hemoglobin provide sources of heme iron, a type of iron that the body absorbs efficiently. The body absorbs 15 percent to 35 percent of heme iron, according to the National Institutes of Health Office of Dietary Supplements. Plant-based iron sources such as soybeans, lentils, kidney beans, spinach, grits and raisins contain nonheme iron, a type of iron more difficult for the body to absorb. The body absorbs only 2 percent to 20 percent of nonheme iron, notes the National Institutes of Health Office of Dietary Supplements. Food components have little effect on heme absorption, but can have a significant effect on nonheme absorption.
Absorption Inhibitors
Food components that can inhibit iron absorption include tannins found in teas, calcium in milk and dairy products, polyphenols in wine and tea, phytates in legumes and whole grains, and proteins in soybeans, according to the National Institutes of Health Office of Dietary Supplements. Coffee and cereals may also inhibit iron absorption, according to MedlinePlus.
Absorption Boosters
Food components that boost nonheme iron absorption include meat proteins and vitamin C. Try to eat nonheme iron sources with these foods whenever possible. For example, have cooked spinach with tomatoes, a source of vitamin C, or have grits and raisins with a cup of orange juice. Or pair lentils or spinach with a meat protein such as turkey, a good source of heme iron.
Other Factors
A variety of other factors can affect iron absorption. Iron absorption increases when the body's iron stores are low, and decreases when its stores are high to protect against iron overload. Gastrointestinal disorders affecting the small intestines, such as Crohn's disease and celiac disease, may cause chronic malabsorption of iron.
Iron Deficiency
People at risk of iron deficiency include vegetarians and vegans, pregnant women, teenage girls and women of childbearing age, and patients with kidney failure. Symptoms of iron deficiency include weakness, fatigue, decreased immune function, difficulty concentrating, irritability, headaches, pale skin, shortness of breath, brittle nails and sore or inflamed tongue. Iron supplements can help prevent and treat iron deficiency anemia. Ask your doctor before adding supplements to your diet.
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