Iron Deficiency in Athletes: The Hidden Barrier to Peak Performance?

Iron may play a critical role in athletic performance

Iron is a key component of hemoglobin and myoglobin, proteins responsible for oxygen transport and storage in muscles, essential during aerobic exercise. When you’re exercising, especially in endurance sports, your muscles need a constant supply of oxygen to produce the energy they need to keep going. This process, known as aerobic respiration, is heavily dependent on iron (iron is what bind oxygen for transport in the body).

current recommendations for iron intake in men and premenopausal women do not take into account higher demands that attributable to exercise or sport.

There is past research that suggests athletes, specifically endurance athletes, may have iron needs that exceed the recommended intake by up to 70% (PMID: 38068803). However, other research shows that iron supplementation does not affect endurance performance if an iron deficiency is not present.

A recent study published in Nutrition (PMID: 39002373) highlights that iron deficiency is surprisingly common among athletes, particularly in female athletes, with nearly 20% affected (35% of total athletes including males). This deficiency can lead to reduced VO2 max, a key indicator of endurance (aerobic) performance.

The study looked at over 1100 athletes and showed that those with iron deficiency had significantly lower VO2 peak values, impacting their endurance capacity. Interestingly, the most iron-deficient athletes were females <19 years old.

findings:

• Iron deficiency without anemia still contributes to diminished athletic performance, especially in endurance sports.
• Nearly 35% of athletes, with higher rates in female athletes, suffer from iron deficiency, which was linked to lower VO2 peak levels.

Recommendations: Regular screening of iron levels, particularly in high-risk groups like female athletes, and ensuring adequate iron intake through diet or supplementation (under medical supervision, in this case) can help prevent performance declines.

For athletes (especially young ones), maintaining optimal iron levels is not just about avoiding anemia, it's also about maximizing your performance potential.

https://www.sciencedirect.com/science/article/pii/S0899900724001655?via%3Dihub

Chapters

• 0:00 The Importance of Iron in Athletics
• 7:10 Optimizing Athletic Performance Through Iron

Transcript

Speaker 1: 0:00

Hello everyone, I'm William Wallace and you're listening to Daily Value. Today, we're going to be looking at the critical role iron plays in athletic performance. This was brought on by a very recent publication in the journal entitled Nutrition, finding that iron deficiency is common amongst athletes and that it may, in fact, reduce performance, notably reducing the probability that an athlete would reach their peak oxygen consumption, that is, their VO2 max, during exercise. So, whether you're an elite athlete or someone who trains regularly, iron is a micronutrient you can't afford to overlook. Today's discussion will break down the findings, discuss the physiological mechanisms at play and explore what this means for your training and performance. As always, I must preface with the disclaimer that this video is being generated purely for educational purposes. The contents of this video do not constitute medical advice and are not meant to substitute for standard medical practice. Please consult with your primary health care practitioner before beginning any nutrition or supplement-based protocols that we go over here today. First, let's talk about why iron is actually important to athletic performance.

Speaker 1: 1:10

Iron is a component of hemoglobin, the protein in your red blood cells that carries oxygen from your lungs to your muscles. It's also a part of myoglobin, which stores and releases oxygen within your muscles. Iron itself is what binds oxygen in hemoglobin and myoglobin, so no iron means no oxygen transport to working muscles. When you're exercising, especially in endurance sports, your muscles need a constant supply of oxygen to produce the energy they need to keep going. This process, known as aerobic respiration, is heavily dependent on iron. Iron also plays a role in the production of ATP, the energy currency of the cell, through its involvement in the electron transport chain within mitochondria. This means that not only does iron help transport oxygen in the body, but it also helps your muscles use that oxygen to generate energy efficiently. As such, iron deficiency or insufficiency is primarily related to impaired aerobic performance, with a greater loss in performance the more severe an iron deficiency becomes. Now, sure enough, current recommendations for iron intake in men and premenopausal women do not take into account higher demands that are attributable to exercise or sport. The current recommendations are 11 milligrams for males, 14 to 18 years old and 8 milligrams for men, 19 years and older. For females, the recommendation is 15 milligrams for 14 to 18 year olds and 18 milligrams for 19 to 50 year olds.

Speaker 1: 2:40

There is research in the past that suggests athletes, specifically endurance athletes, may have iron needs that exceed the recommended intake by up to 70%. However, other research shows that iron supplementation does not affect endurance performance if an iron deficiency is not present. Iron supplementation tends to benefit athletes most if ferritin blood levels are under 20 micrograms per liter. Now there are two types of iron deficiency to discuss here, and those are iron deficiency without anemia present and iron deficiency with anemia present. Iron deficiency without anemia is when iron stores are low but there's still enough iron to produce hemoglobin at normal levels. Oxygen transport capacity is not thought to be diminished in the case of iron deficiency without anemia. However, past research has suggested that athletic performance still diminishes in the case of iron deficiency without anemia. Without anemia, likewise, there's mounting evidence that even a marginal iron deficiency can be detrimental to things like mental health and development in children and young adults, which suggests possible effects on physical performance as well, which brings us to the research that was just published.

Speaker 1: 3:55

This study that we are about to discuss involved 1,100 athletes and was conducted in Germany. These athletes were grouped based on their iron levels, with iron deficiency defined as a ferritin level below 20 micrograms per liter, regardless of whether they had anemia or not. The researchers then analyzed the athlete's VO2 peak, which is the maximum amount of oxygen that their bodies could utilize during intense exercise. That's an indicator of endurance capacity. So what did the study find? Iron deficiency was surprisingly common, affecting nearly 20% of the athletes, that's males and females, with a much higher prevalence among female athletes. Over 35% of the athletes in the whole study that had iron deficiency were females. Females obviously experienced more iron loss than males via menstruation, so that's most likely the reason for higher rates in females in this case. Interestingly and unsurprisingly, iron deficiency was most pronounced in females under the age of 19. Past studies on similar topics have found the exact same thing. Now, another interesting finding was that athletes with iron deficiency had significantly lower VO2 peak values compared to those with normal iron levels. Specifically, the study found that iron deficient athletes were less likely to reach a VO2 peak of 50 milliliters per minute per kilogram of body weight. Now again, vo2 peak. Here is a benchmark associated with high aerobic fitness. That particular number is used sometimes to signify a well-defined aerobic fitness level in athletes.

Speaker 1: 5:31

After running some separate analyses, the researchers concluded that iron deficiency independently contributed to reduced endurance performance. In this case, contributed to reduced endurance performance. In this case, when your body lacks iron, it can't produce enough hemoglobin, leading to a reduced oxygen carrying capacity in your blood. This means less oxygen is delivered to your muscles, impairing their ability to perform aerobic respiration efficiently. As a result, your body might rely more on anaerobic pathways for energy, which would lead to a quicker drop in blood pH and possibly earlier depletion of glycogen levels, both contributing to fatigue. Moreover, iron deficiency affects more than just oxygen transport. It also impairs the function of key mitochondrial enzymes involved in the electron transport chain. This means your cells produce less ATP per molecule of oxygen, which, in theory, would diminish endurance performance.

Speaker 1: 6:27

So what does this mean for you as an athlete or an avid exerciser? First, it might be worth getting your iron levels checked. This is especially true for female athletes, vegetarians and those who engage in high-intensity training, as these groups are at higher risk for having insufficient iron. The CDC currently recommends screening for anemia of all non-pregnant women every five to ten years throughout their childbearing years. However, the National Athletic Trainers Association does not currently recommend anemia screening in athletes that are asymptomatic. This could potentially cause some young female athletes to look past even a marginal iron insufficiency, which may impact their performance negatively.

Speaker 1: 7:10

In terms of prevention, ensuring an adequate intake of iron-rich foods is crucial. Red meat, poultry and fish are excellent sources, while plant-based sources like beans, lentils and spinach can actually also contribute especially when paired with vitamin C rich foods to enhance the absorption of iron, either by keeping iron in its reduced state or by forming a bioavailable complex with iron. In some cases, iron supplements may be necessary, but these should always be taken under medical supervision to avoid any potential side effects like gastrointestinal discomfort or iron overload, which isn't something to be understated. In conclusion, this study underscores the significant impact of iron deficiency on athletic performance, particularly in endurance sports, and particularly in young female athletes. In endurance sports, and particularly in young female athletes, by understanding the crucial role of iron and oxygen transport and energy production, athletes can take proactive steps to ensure they're not held back by a preventable deficiency. Thank you for tuning in to Daily Value. If you found this episode helpful, be sure to subscribe and share with your training partners Now. Until next time, stay healthy.