Enhancing Endurance: Addressing Iron Deficiency in Athletes
Previously, we learned that ketones have a beneficial impact on Erythropoietin (EPO) production and an enhancement in capillary density. These two physiological factors improve the performance of endurance athletes by enhancing the body's oxygen absorption and utilization. You can find more information on ketones and performance in the blog post here.
The ketone blog post prompted an introduction to the iron profile due to the many questions that resulted from ketone/EPO release/red blood cells. So before we get going, it is important to clarify that this is not medical advice, but rather a summary of information found in textbooks and research papers that most athletes can access at their fingertips. If you have any concerns, please consult your physician.
Questions we will attempt to answer:
1.What is the function of iron?
2. What are the levels and types of iron intake?
3. What are the key aspects of iron deficiency: essential metrics, definition, and progression?
4. What factors lead to iron deficiency in athletes?
5. What are possible treatment options?
6. Summary
1.Function of Iron
Around 5% of the general population typically experiences iron deficiency, whereas in the athletic population, the diagnosis of iron deficiency occurs in 35% of cases (Noakes 2001) (Williams 2005). In other words, athletic or more active individuals seem to be more prone to iron deficiency issues.
Iron is involved in the formation of compounds that transport and utilize oxygen with most of the iron going to making hemoglobin which binds oxygen and carries it from the lungs to the energy factories in the muscle called mitochondria (see previous post here: https://www.thethreshold.coach/single-post/ketones-and-performance-ii-post-exercise-use). Iron is also used in the formation of myoglobin which stores and transports oxygen in the muscle as well as in the formation of ferrochromes which are present in the energy factories mentioned above and are essential for the production of energy currency called ATP (that makes muscles contract).
The remainder of the iron is stored in the tissues in the form of protein compounds called ferritins. Other places where iron is stored (as ferritin) are the spleen, liver, and bone marrow. 30% of iron is stored and 70% is involved in oxygen metabolism
2.Levels and Types of iron intake
Iron is a trace mineral which means it is required in quantities of less than 100mg a day with around 1-1.5mg lost daily from the body. However, because the ability to absorb iron from food tends to be quite low with around 10% bioavailability, it means that the recommended daily allowance is around 10 times the need. See the table below for the Upper Limits of Iron intake by the National Academy of Sciences 2006.
Iron Intake |