This is adapted from the book, Eat Smart, Play Hard, by RW USA Nutrition Editor Liz Applegate.
You must have an adequate amount of iron in your blood to get oxygen to your muscles. If you dont get enough, you experience extreme fatigue, lagging performances, and are often more susceptible to colds. Since you may be losing some iron in your sweat and urine, and because exercise itself can hamper your ability to absorb the mineral, you need to pay careful attention to your intake.
Before you start taking supplements, however, try getting more iron in your diet. To reach the recommended amount, which is 10 milligrams for men, 15 milligrams for women age 50 and under, and 10 milligrams for women over 50, consume iron from a variety of sources. Meat is your best source because it contains heme iron, which is the most readily absorbable form. Other good sources of iron are fortified cereals, lentils, and broccoli. Eat a food that is rich in vitamin C, such as strawberries or bell peppers, with your iron source because vitamin C significantly improves iron absorption.
My recommendation: Stay away from supplements that contain more than 15 milligrams of iron. Too much iron can hamper your zinc absorption, making you just as tired as if you had low iron.