Vitamins and minerals are necessary for energy production and muscle building pathways. Unlike carbohydrates, protein and fat, these micronutrients do not provide energy (calories) and are needed in very small amounts. Some nutrients can be manufactured in the body, but many of the essential nutrients must be supplied daily through diet. Athletes need to recognize that vitamins and minerals are vital to helping the body and muscles use food for fuel. The body cannot use energy from carbohydrates, fat and protein effectively without them, which can negatively impact performance.
For most athletes, vitamin and mineral needs can be met through a balanced intake of whole grains, lean meats, poultry, fish, low-fat dairy, fruits and vegetables. Even strict vegetarians can meet vitamin and mineral needs through a careful selection of a variety of plant-based foods. When athletes have difficulty meeting their vitamin and mineral needs through traditional food intake, nutrient supplementation may be necessary. The coach should keep in mind, however, that sport bars, gels and shakes may already contribute to the athlete’s nutritional needs. Serious nutrient deficiencies are uncommon but still may be a concern. Physical signs such as performance staleness, weakness, apathy, hair, skin and eyesight problems, gastrointestinal distress, frequent stress fractures or illness may be indicators for further medical evaluation.
A daily multivitamin and mineral supplement (with no more than 100% of the recommended daily amount) has been recommended by the American Medical Association for adults. Female athletes may benefit from a multivitamin/mineral supplement with iron, whereas male athletes should look for one without iron unless advised otherwise by a physician.
Supplementation with vitamins and minerals does not improve athletic performance unless the athlete’s diet is inadequate. Athletes should first consult with a physician or qualified nutrition professional to address specific supplementation needs before taking supplements.
Two nutrients that are commonly inadequate in an endurance athlete’s diet are iron and calcium.
• 8 mg/day for Men and Women
Iron is a critical mineral for oxygen use and the production of hemoglobin. Blood hemoglobin carries oxygen from the lungs to the muscles for use in exercise. Iron deficiency is the most common nutrient deficiency in the United States. Iron deficiency anemia, even in its early stages, can have a significant impact on performance. Signs that an athlete may have low iron stores include fatigue, a decrease in performance or frequent illness. endurance athletes are at risk for anemia due to iron sweat losses, gastrointestinal bleeding commonly associated with distance running, and menstrual losses.
Many foods contain two types of iron, heme and nonheme, but the iron is not always easily absorbed. Heme iron, which is found in meat (beef, pork, lamb, veal, poultry and fish), is better absorbed than nonheme iron that is found in plant foods. Foods rich in Vitamin C, such as berries, peppers, citrus fruits and juices, tomatoes, potatoes and broccoli, can help the body absorb more iron.
Athletes should be encouraged to include heme iron sources at least 3-4 times per week and nonheme iron sources and foods high in Vitamin C daily.
• 1,000−1,300 mg/day Men and Women
Calcium is a mineral needed for bone formation and strength. It is also needed for muscle contractions, blood clotting and nerve impulse transmission. Calcium can be lost in sweat and body waste. female athletes and athletes on energy-restricted diets are at risk for inadequate calcium intake. Diets low in calcium can stunt growth and place an athlete at risk for stress fractures and osteoporosis later in life.
Food sources richest in the most absorbable form of calcium are low fat dairy products. One cup of milk or 1.5 oz of cheese can provide 300 mg of calcium. Other foods that provide calcium in a less absorbable form are soybeans, almonds, kale and broccoli. Athletes who are milk intolerant should consider calcium- fortified orange juice or breads that are readily available in the supermarket. Some athletes may need calcium supplementation as a result of a dairy allergy, intolerance or strong food dislike. These athletes should consult with a physician or nutrition professional for guidance.