They’re three of the most important nutrients in a woman’s diet: iron, calcium and folate. Run low on any one of this triad and the first place it will show up is your workout. Active women in particular benefit from the oxygen and energy supplied by iron and folate, and the strong bones and protection against fractures produced by calcium. Studies have shown that most women don’t get enough of at least one of these essential nutrients–but there are ways to make sure you do.
Muscle in more iron
Professional triathlete Karen Smyers knew something was wrong in 1988, when her training took a turn for the worse soon after she’d increased her running mileage. “Whenever I was exercising at high intensity,” she recalls, “I couldn’t sustain my normal pace and had trouble breathing.” Her physician diagnosed an iron deficiency and prescribed iron supplements; Smyers also decided to start eating red meat again. A few months later she was back to normal.
You don’t have to be a triathlete to deplete your iron stores. Any active woman risks doing this, especially if she’s eliminated red meat from her diet or stepped up her workout intensity and duration. Iron deficiency develops over time, often creeping up on you till your morning run turns into a walk or you find yourself gasping for air as if you were running up Kilimanjaro instead of around the track. Iron enables the blood to carry oxygen to the muscles. A deficiency means you’ll have trouble getting enough oxygen to fuel your workout and you’ll tire sooner.
The severest form of iron deficiency is anemia. “The incidence of true anemia in women is actually quite low, about 5 percent,” says thomas Rowland, M.D., of Baystate Medical Center in Springfield, Massachusetts. “But up to half of all female athletes have low ferritin, the main form iron is stored in. These athletes can develop anemia.” rowland adds that women athletes, and runners in particular, are unusually prone to low ferritin levels. Although doctors aren’t sure why this is, they suspect that it may be due to iron losses in sweat or the jarring of high-impact exercise, which can burst blood cells.
Diets low in iron and blood loss during menstruation are what put most women at risk of anemia. A concern about fat and cholesterol has led many active women to limit their intake of one of the best sources of iron, red meat. But the iron found in lean meat, poultry and seafood is absorbed more readily by your body than iron from plant sources. In order to get the 15-milligram recommended daily allowance (RDA) of iron, try adding lean beef to a high-carbohydrate bean chili or turkey to lentil soup. You can maximize the iron your body will absorb from plant sources by combining those with foods rich in vitamin C. Top iron-fortified cereal with strawberries and drink a glass of orange juice. Beware of coffee and tea; they contain tannins that decrease iron absorption–another good reason to limit your intake.
If you think you might be getting too little iron, ask your physician. The shortterm treatment to restore iron levels should have no ill effects, but you don’t want to take iron indiscriminately or you may end up taking too much. Doses of 25 mg a day can decrease your absorption of zinc, a mineral necessary to metabolism, would healing and immunity. And although the research is still inconclusive, excess iron may increase your risk of cancer or heart disease. You’re safe downing a daily multivitamin with the RDA of iron, but ask your doctor if you’re thinking of taking more than that.