Performance Nutrients (cont.)
Like vitamins, certain minerals are involved in energy metabolism, muscle contraction and oxygen transport, and regulating heart rate. Calcium in particular is involved in all kinds of muscle contraction, bone mass, nerve transmission and secretion of hormones, all important to athletic performance.
Dairy products are very concentrated sources of calcium and for most individuals provide about seventy-five percent of their total calcium intake. For vegetarian athletes, calcium-fortified foods like orange juice, tofu, and cereals, can supplement the diet. Other vitamins required for healthy bones are vitamin D, magnesium, and vitamin K.
Iron is essential for the development of hemoglobin, which transports oxygen to muscle cells. Iron deficiency is the most common form of nutrient deficiency in the United States. It is estimated that approximately twenty-five percent of female athletes are iron deficient. True iron deficiency will decrease a person’s athletic performance. Symptoms include fatigue and poor ability to recover from training. Development of iron deficiency can result from an inadequate diet, vegetarian diets, and fad diets (like very high carbohydrate diets). Fish, meats, iron-fortified cereals, lentils, kidney beans, and prune juice are all good sources of iron.
Zinc is another important mineral for athletes. An adequate amount of zinc keeps your immune system strong and promotes healing of wounds and injuries. Zinc is also a component of several enzymes involved with energy metabolism and protein synthesis. Plant sources of zinc are garbanzo beans, lentils, lima beans, and brown rice. However, animal sources of zinc are better absorbed. Good sources of zinc are meat, turkey, yogurt, and seafood.
Moderately active people and recreational athletes rarely need supplementation for vitamins and minerals. Following the dietary guidelines for a balanced diet should be sufficient to meet nutrient needs. However, if fatigue or other physical symptoms are present, it is important to seek professional help and not self-diagnose the need for supplements. In most cases, a variety of wise food choices is sufficient to meet the needs of active people and recreational athletes.