Commonly discussed topics for athletes include carbs, protein, hydration, sleep, and recovery.
Micronutrients are often overlooked by the public, yet prove to be just as vital for training and maintaining a healthy body as the topics previously listed. This article teaches you more about your specific needs, the components needed to optimize athletic performance on a plant-based diet, and how to get the competitive edge you’ve been looking for. Let’s begin!
What Is Iron?
Iron is a trace mineral in the body and an extremely important one for exercise. The main function of iron is to synthesize hemoglobin and myoglobin. Ooo, two big science words…break it down! Simply put, hemoglobin is a protein found in red blood cells (heme = iron, globin = protein). These proteins carry oxygen inside red blood cells from the lungs to various tissues. Billions of cells in the body need oxygen to maintain and build itself, so hemoglobin truly is an important player in the transportation of oxygen to active and working muscle tissues!
Myoglobin on the other hand is primarily located in muscle tissue (myo = muscle, globin = protein). It serves as a local reservoir for oxygen (think: storage unit), and can provide oxygen temporarily to the muscle tissue during intense periods of activity. Having high concentrations of myoglobin is beneficial because it allows organisms to function without as much breathing. This is why myoglobin is found in abundance inside muscle tissues of seals and whales (1). Endurance exercise can help increase myoglobin in muscle cells due to the increase in aerobic respiration (2). However, abnormally high myoglobin amounts in the blood or urine may infer muscle tissue or kidney damage.
By having adequate iron stores, one can optimize aerobic capacities and abilities. On the flip side, lack of iron can cause decreased exercise endurance and fatigue which makes sense because not enough oxygen is being transported to tissues or muscles. This deficiency is called iron-deficient anemia and poses high risk among athletes, specifically, women. This is because most women have lower energy consumption and lower intake of meat, combined with additional iron losses from sweat, menstruation, and excretion of ruptured red blood cells (3). Additionally, distance sports such as running cause destruction, and eventually a shorter lifespan, to red blood cells in the feet due to constant pounding during the footstrike motion. To help you meet recommended levels, five animal-based sources rich in heme-iron are listed below. Be aware that gender, exercise type, and dietary intake all play a large role in iron status, and supplementation may be needed.
If animal products are not in your diet then special concern should be taken to seek out plant-based sources. Clueless? I’m so glad you asked…
Legumes (beans, lentils, etc.)
One last note: Heme vs. Non-Heme Iron
Heme iron comes from animal-based foods, and non-heme iron comes from plant-based foods. In the body, heme iron is most easily absorbed at up to ~40%. Non-heme iron contains only ~10-15% heme and therefore has a much lower absorption rate. When getting all, or the majority, of your dietary iron from non-heme sources consider increasing your intake and pairing foods with a vitamin C source to help increase absorption. Studies show up to a 67% increase in absorption when 100mg of vitamin C is taken with an iron rich meal (100mg = 1 cup of oranges) (4). Studies also have shown that vegetarian and vegan diets, when done properly, result in equal if not higher amounts of iron than when meat is included (5).
Foods rich in vitamin C include dark leafy greens, bell peppers, citrus fruits, strawberries, and melons.
Recommended Daily Iron Intake:
13.7-15.1mg/d for children ages 2-11 years
16.3mg/d for ages 12-19 years
19.3-20.5mg/d for men over 19 years
17-18.9mg/d for women over 19 years.
*Vegetarians and vegans should multiply that number by 1.8 due to the lower absorption from non-heme sources.
*Food label percentages are based on 18mg/day iron requirements
If you have questions or concerns regarding diagnosis, symptoms, deficiencies, supplementation, etc. please reach out with the call link HERE, or contact your primary care provider.
1) Mirceta, S., Signore, A. V., Burns, J. M., Cossins, A. R., Campbell, K. L., & Berenbrink, M. (2013, June 14). Evolution of Mammalian Diving Capacity Traced by Myoglobin Net Surface Charge. Retrieved October 18, 2019, from https://science.sciencemag.org/content/340/6138/1234192
(2) OpenStax. (2013, March 6). 10.6 Exercise and Muscle Performance. Retrieved October 18, 2019, from https://opentextbc.ca/anatomyandphysiology/chapter/10-6-exercise-and-muscle-performance/
(3) Rosenbloom, C. A. (2012). Sports Nutrition: A Practice Manual for Professionals. (E. J. Coleman, Ed.) (5th ed.). Academy of Nutrition and Dietetics.
(4) Hallberg, L., & Hulthén, L. (2000, May). Prediction of dietary iron absorption: an algorithm for calculating absorption and bioavailability of dietary iron. Retrieved October 18, 2019, from https://www.ncbi.nlm.nih.gov/pubmed/10799377
(5) Craig, W. J., Mangels, A. R., & American Dietetic Association. (2009, July). Position of the American Dietetic Association: vegetarian diets. Retrieved October 18, 2019, from https://www.ncbi.nlm.nih.gov/pubmed/19562864