By Rebecca Scritchfield, MA, RD, LD
Sports Nutritionist And Acsm Health Fitness Specialist
March/april 2009
For The Washington Running Report
There are many reasons active people may feel low in energy, such as eating too few calories, not getting enough sleep, stress, and overtraining. If you do not eat enough healthful foods or if you habitually get little sleep, chances are you are going to feel tired. But your low energy may be related to lack of iron. People who experience fatigue, weakness, pale skin, headache, and irritability may have low iron levels. Others may have severe iron depletion called anemia or “tired blood.” Often there is a nutrition connection.
Iron is a mineral with many functions. First and foremost, iron helps carry oxygen to all the body’s cells, where it is used to produce energy. After releasing oxygen, it removes carbon dioxide waste. Also on iron’s “resume” is protecting you from infections as part of your immune system, creating vitamin A, producing collagen (which holds body tissues together), and making body proteins (amino acids).
If your iron is low, you cannot carry as much oxygen so you may feel run down and tired even if you eat enough calories and get plenty of rest. It is important for active people to get enough iron because strenuous exercise uses it up more quickly. Athletes, especially women, vegetarians, and those competing in endurance events are known to have low iron. Endurance sports, such as marathon running, promote iron loss through sweat, urine, feces, and gastrointestinal bleeding.
Even a small iron shortfall can cause problems for athletes. Low iron can impact performance by slowing your ability to generate energy, increasing your exercise heart rate, causing intense muscle “burning,” reducing your ability to recover quickly, and increasing chances of injury-all situations you would probably rather avoid.
Beginning runners, especially first-time marathoners and half-marathoners, should pay attention to signs of fatigue and weakness when first starting a training program. “Sports anemia” is often caused by increases in blood volume as a result of training, which decreases iron concentration in the blood. Sports anemia is not a true iron deficiency. As your body adapts to physical activity your fatigue should go away as long as you are getting enough iron.
Meeting your daily iron needs through food is the best way to maintain your iron levels. Men should aim for 8mg of iron and women need 18mg of iron a day. Unfortunately, most people don’t reach these levels on a daily basis. In fact 75 percent of females 18 to 44 do not eat enough iron-rich foods and at least 50 percent of female endurance athletes have iron depletion.
Don’t panic just yet. Getting enough iron in food is easy. The front-runner foods naturally high in iron content are beef (4oz), kidney beans (1 cup), and spinach (1/2 cup cooked) with 3mg each. Grains, such as cereal, are often fortified with iron. One cup of Total 100% has all 18mg that women need. Both Wheaties and Cheerios offer the full 8mg men need.
You can even add iron to foods just by cooking. Acidic foods, such as tomatoes and eggs, can absorb the iron from the skillet. Make eggs in a cast iron skillet and you will increase the iron content from 1.5mg to 5mg. Use a cast-iron pot to simmer spaghetti sauce and chili for three hours to boost iron levels from 3mg to up to 90mg in just half a cup!
It is possible to get “too much of a good thing.” Although rare, a genetic condition called hemochromatosis causes too much iron to be stored. A person may develop diabetes, bronze-colored skin, and an enlarged liver. This condition is ten times more prevalent in males than females and usually shows up in adults over 30. The safe Tolerable Upper Intake Level (UL) is 45mg per day for people over 14 years old. Some iron supplements can be dangerous because they easily provide more iron than the body can use.
You can find out how much iron you are getting from foods and if you should have your iron levels tested through a nutrition assessment by a dietitian. Before thinking about taking an iron supplement, ask your doctor for a blood test to determine your iron status. This will help guide the best course of treatment, including supplementation needs and changes to your usual food intake. You may even have a type of anemia not related to iron-so get the facts first.
Endurance athletes, especially pre-menopausal women, should have their iron tested by a physician periodically because of their increased risk for low iron levels and potential performance-hindering problems. Vegetarian and vegan athletes should meet with a registered dietitian to develop a fueling plan that will meet iron and other vitamin and mineral needs.
All athletes should remember that it is very easy to get enough iron in a healthy sports diet. Include iron-fortified cereal or toast with orange juice at breakfast, enjoy three bean chili and a whole grain roll at lunch, and fuel up on wheat pasta with tomato and meat sauce at dinner. Snack on dried apricots, plums, raisins, and pretzels. These are just some of your options for a high performance, high iron, “winning” sports menu.
In health, Rebecca
Rebecca Scritchfield is a registered dietitian specializing in performance nutrition and weight management. She regularly runs marathons and half marathons in the DC area. Visit her Web site and blog at www.elitenutritiondc.com. Send correspondence regarding this article to: mrscritchfield@gmail.
http://www.runwashington.com/news/776/309/Low-on-Energy-Check-Your-Iron.htm
