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Iron is an important nutrient for athletes

October 10, 2000

Iron is an important nutrient for athletes



Whether pumping iron, training for the Iron Man Marathon or just trying to stay fit, iron is one nutrient that needs to be in balance for peak performance.

Iron-deficiency anemia is relatively common among teenage girls and women. It's even more common among female athletes, especially runners and ballet dancers. When women with marginal iron stores stop menstruating as their bodies attempt to conserve iron, they may be setting themselves up for the early onset of osteoporosis.

Iron gives the body energy by helping carry oxygen from the lungs to muscles during exercise. When iron stores become low, the flow of oxygen to the muscles slows. As a result, carbohydrates and fats are not burned as efficiently and performance suffers.

Female runners are particularly susceptible because of the iron they lose during menstruation. Male runners, however, are by no means immune. Iron is commonly lost through sweat - one reason both male and female runners in long-term, high-volume training are at risk. Other possible mechanisms include foot strike haemolysis, a breakdown of red blood cells in the foot, and losses through destruction of red blood cells or bleeding in the gastrointestinal or urinary tracts. There is also some evidence that runners may have more difficulty absorbing the iron in their foods than nonrunners.

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Regardless of how the iron is lost, the bottom line is clear:

Athletes, particularly runners and especially women, should take pains to eat an iron-rich diet.

Two sources of iron in food


There are two main sources of iron in food: Heme iron and nonheme iron. Heme iron is easier for the body to absorb. Heme iron, from the hemoglobin of animals, is found in lean red meat, liver, poultry, fish, oysters and clams. The body may absorb as much as 15 percent of the iron available in heme sources.

Nonheme iron can be harder to absorb. It's found in nuts, dried peas and beans, whole-grain breads and fortified cereals, fruits and molasses. Typically the body will manage to absorb only 4 to 5 percent of the iron in nonheme sources. Eating these foods together with meat, poultry, fish or vitamin C-containing foods will increase the absorption of iron from nonheme sources. In contrast, eating nonheme sources of iron together with foods containing phytates, carbonates, oxalates, phosphates or tannins will decrease the body's absorption of iron.

Phytates are found in nuts, legumes, and the germ and bran of cereal grains. Oxalates are found in spinach, cocoa and tea. Tea and coffee are important sources of tannins. Translated into food choices, to maximize the iron in the morning toast or cereal, it's better to drink orange juice than coffee or tea.

It's best to take iron supplements only under the advice of a physician or dietitian. Too much iron can be as detrimental to your health and performance as too little. A better choice is to make sure your iron reserves never dwindle by eating a variety of iron-rich foods.

Lynn F. Little is a family and consumer sciences extension educator for Maryland Cooperative Extension, Washington County. Maryland Cooperative Extension programs are open to all citizens without regard to race, color, sex, disability, age, religion or national origin.

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