Many men and women who engage in regular, intense exercise such as running, competitive swimming, and cycling have “marginal or inadequate iron status”. Possible explanations include increased gastrointestinal blood loss after running, a greater turnover of red blood cells, and the fact that red blood cells within the foot can rupture when you pound the ground during a long run. For these reasons, the need for iron may be 30% greater in those who engage in regular intense exercise.

Female athletes, distance runners, and vegetarian athletes are the most likely to experience iron deficiency. It is particularly important for these folks to consume recommended amounts of iron and to pay attention to dietary factors that enhance iron absorption. If appropriate nutrition (enter spinach salad with mandarin oranges and walnuts) does not promote normal iron status, iron supplementation may be required. In one study of female swimmers, researchers found that supplementation with 125 mg of ferrous sulfate per day prevented iron depletion.

Vitamin C will improve the absorption of iron. Tannins (found in tea, wine), calcium, polyphenols, and phytates (found in legumes and whole grains) can decrease absorption of iron. Some proteins found in soybeans also inhibit iron absorption, and caffeine messes up the absorption of pretty much everything. So if blood tests indicate that you need an iron supplement, don’t take it with your milk and cereal in the morning, or your tea or coffee. Have it with some citrus fruit instead.

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