Keeping your body healthy with balanced nutrition is important for sports performance and for maximizing the benefits you get from a workout. Not only does your body need macronutrients like protein, fat, and carbohydrates, it also needs co-factors like vitamins and minerals. Researchers have long been intrigued by the idea that certain vitamins and minerals might improve sports performance. Now a new study reveals the role of iron, a mineral your body needs in trace amounts, plays in exercise capacity in women.
Iron Supplements, Strength and Sports Performance
Researchers at the University of Melbourne recently looked at the effects of iron on exercise performance in women. After analyzing a number of previous studies, they found women in their child-bearing years that supplemented with iron showed improvements in maximal and submaximal exercise performance. Women taking iron supplements experienced a lower heart rate during sub-maximal exercise. In other words, their heart rate didn’t have to increase as much to successfully deliver oxygen to tissues. They were also able to achieve a higher level of performance during maximal exercise. Research also shows iron supplements decrease lactate accumulation during high-intensity exercise so you can go a little longer without experiencing fatigue.
When you consider the role iron plays in oxygen delivery, these results aren’t surprising. Iron is bound to hemoglobin the oxygen-carrying part of red blood cells. When oxygen attaches to hemoglobin, it binds to the iron portion of the hemoglobin molecule. Without iron, oxygen can’t be carried to the tissues that need it. Iron is also necessary to make hemoglobin. That’s why people who don’t have enough iron in their body sometimes develop iron-deficiency anemia. The classic symptoms of iron deficiency anemia are reduced exercise tolerance, fatigue, lightheadedness, and rapid heart rate. Iron plays an essential role in delivering oxygen to tissues during exercise and at rest and oxygen delivery is vital for exercise performance. It plays a role in cognitive function too. If your iron levels are too low, you may feel less motivated to exercise. Iron is also important for a healthy immune system.
How common is an iron deficiency in female athletes? Some research shows up to a third of all female athletes of child-bearing age have low iron levels. Although they may not have iron deficiency anemia, they have fewer “iron reserves.” Over time this could develop into iron deficiency anemia. In the meantime, it may subtly reduce exercise performance, especially during endurance exercise. The best measure of body iron stores is a blood test that measures ferritin, the storage form of iron. It’s only when ferritin drops below a critical level that hemoglobin synthesis is affected and iron deficiency anemia develops. You can be low in iron yet still have normal hemoglobin.
Does This Mean You Should Take Iron Supplements?
Supplementing with iron can be harmful if you don’t need it. At higher levels, iron acts as a “pro-oxidant,” meaning it can damage cells. Taking iron as a supplement can also interfere with the absorption of other minerals like zinc. This can create a nutritional imbalance. In addition, iron supplements can interact with some medications. Blindly taking an iron supplement to improve exercise performance isn’t a good idea. Some people have a condition called hemochromatosis where they store too much iron. These can damage organs and tissues including the heart and liver.
What this study shows is the importance of monitoring your iron level. During the child-bearing years, women are at risk for iron deficiency because they lose iron monthly through menstrual bleeding. This changes after menopause when iron requirements decrease. That’s why women who have reached menopause shouldn’t take a multivitamin with iron or supplement with iron unless their iron level is low.
Measuring Iron
Your doctor can do a blood test called an iron panel to see if you’re low in iron. An iron panel measures the amount of iron in your blood, total iron binding capacity (the ability of your body to bind iron) and ferritin, the storage form of iron. By looking at the results of a full iron panel, you can identify lower iron levels that may be impacting your exercise performance. These tests are a more sensitive way to check for iron deficiency than measuring a hemoglobin level. If you’re pre-menopausal, it’s a good idea to check an iron panel every year especially if you eat a vegetarian or vegan diet. Keep in mind that vigorous exercise can falsely elevate your ferritin level, so don’t exercise before checking an iron panel.
Even if your hemoglobin is normal, you may benefit from an iron supplement if your stored iron levels, as measured by ferritin, is low. Iron deficiency without anemia is a fairly common problem in female athletes. Some research also shows that sports training itself is associated with a drop in iron levels. Distance runners are at particularly high risk for iron deficiency.
The Bottom Line?
If you’re deficient in iron it can affect your exercise performance and your endurance. If you eat a vegetarian diet or have heavy menstrual periods, monitor your iron status closely. Also, if you notice a decline in exercise performance, check an iron panel as soon as possible. On the other hand, if you have normal iron levels, it’s not a good idea to take an iron supplement.
References:
Medscape Family Medicine. “Nutrition and Athletic Performance”
Medical News Today. ” Women Need Iron and Calcium for Strength and Exercise Performance”
J. Nutr. June 1, 2014 jn.113.189589.
National Institutes of Health. “Iron”
Medscape Family Medicine. “Iron Deficiency in Athletes”
Related Articles By Cathe:
How Do Low Iron Levels Impact Exercise Performance?
4 Reasons Why Iron Deficiency Is More Common in Athletes
Exercise and Anemia: If You Work Out Do You Need More Iron?
Iron Absorption: How Much Iron Are You Absorbing From Your Diet?
