We all know that a healthy well balanced diet is important for athletic performance. As we increase our exercise we put stresses on our bodies that can lead to an increase in your daily nutritional needs. The one that most people have heard of is increasing carbohydrates when distance running aka “carbo-loading” or “carbing up.” We should know by now that hydration plays a major role in most bodily functions, and that proteins help build muscle/ muscle recovery. One that is gaining more attention lately is iron. Iron is an important mineral element used by the body in a variety of metabolic and physiologic processes. These processes are highly active when the body is undergoing physical exercises. This key nutrient tends to go unnoticed until it is problematic.
Iron plays a key role in oxygen transport and fuel utilization (Schumacher et al. 2002). Symptoms for iron deficiency may eventually include reduced endurance capacity, lethargy, poor concentration, irritability and increased risk of injury (Rockwell & Hinton 2005). This is because when an athlete operates without adequate iron, less oxygen is delivered to the muscles, maximal oxygen consumption (VO2max) drops, and physical performance suffers (Rockwell & Hinton 2005). Additionally, too little iron may impair immune and other physiological functions (Beard & Tobin 2000).
So why is this an issue for athletes? An athlete can lose iron through sweat, urine and the gastrointestinal tract (Rockwell & Hinton 2005). Female athletes are at greater risk of iron deficiency amenia because of the added losses through menstruation.
While the stress of exercise is a significant factor, dietary choices cause most cases of iron depletion. Vegetarian athletes are especially vulnerable in this regard, because they avoid animal sources of dietary iron, known as heme iron, which is more effectively absorbed than the nonheme iron from plant sources (Rockwell & Hinton 2005). In fact, heme iron provides up to one-third of all absorbed dietary iron (Rockwell & Hinton 2005).
Athletes who regularly restrict their caloric intake in order to lose or maintain a certain weight are also probably getting inadequate iron, which can result in iron deficiency anemia, unless they are specifically focusing on eating foods that are rich in iron. However, that kind of focus takes considerable effort and planning, which is why so few athletes stick to that approach.
Combine plant nonheme iron sources, such as lentils and green, leafy veggies, with foods that are high in vitamin C, such as orange juice. Use cast-iron cookware, which may increase the iron content of cooked foods. Don’t drink tea and coffee while eating iron-rich foods, since both beverages can impair iron absorption. Avoid pairing iron-rich foods with certain grains, such as wheat bran, or with veggies such as spinach, rhubarb, chard and beet greens. These foods contain chemical compounds called phytates and oxalates, which impair iron absorption. Don’t mix calcium-rich beverages, like milk and fortified orange juice, with foods that are high in iron, since calcium can also inhibit iron absorption (Rockwell & Hinton 2005).
Animal Sources (heme iron) Plant Sources (nonheme iron)
liver iron-enriched breakfast cereal
roast beef, steak nuts (cashews, almonds)
roast lamb, sweet corn, potato
eggs lentils, baked beans in sauce, bean soup, chili with beans
dark-flesh tuna, whole-grain foods (oatmeal, sunflower seeds)
lean pork, ham enriched bread, mostly wholemeal
skinless chicken, green, leafy vegetables (broccoli, spinach, cabbage)
white fish, dried fruit (prunes, apricots, raisins); fresh fruit
soy (tofu, soybeans, soymilk)
Burke & Deakin 2000; Rockwell & Hinton 2005.
American Dietetic Association, www.eatright.org
Breaking News on Supplements and Nutrition (North America),
Ohio State Buckeye Sports Nutrition (Minerals), www.hec.osu.edu/ sportsnut/nutrients/minerals.htm
Australian Institute of Sport (Sports Nutrition), www.ais.org.au/ nutrition/index.asp