As an endurance athlete, you may be wondering: do athletes need more iron? With the extra stress allotted to exercise, making sure athletes get sufficient nutrients is important.
Here is everything you need to know about iron and athletic performance.
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Disclaimer – This post is for informational purposes only and is not for diagnosing or treatment. See your medical provider or Registered Dietitian for individual recommendations applicable to your health and health history.
If you’ve been taking your running seriously, you know that good nutrition is essential for improving your performance.
You want to make sure you’re adequately fueling yourself by having a pre-workout snack before a long run.
During your run, you’re getting in your energy gels for quick energy to sustain your efforts.
In addition, you prioritize good carbohydrates after a run to replenish your glycogen stores and recover your muscles. You may do this through a recovery drink or knowing what to eat after a long run.
These are all great and important things to do!
But, what if your micronutrient status is off? For example, you’re deficient in Vitamin D, calcium, and/or iron?
Athletes are actually at a greater risk for iron deficiency than those who are sedentary, and this article will explain the importance of iron for athletes.
Importance of Iron for Athletes
Why exactly is iron so important for runners and athletes? Many reasons!
- Transporting oxygen to the tissues and muscles – As a component of hemoglobin and myoglobin, respectively, iron helps allow your body to transport iron to tissues and muscles to help support your exercise workload. Iron deficiency may impact your energy levels, workload, recovery and training.
- Healthy connective tissue – Iron is a component of your connective tissue, so it’s necessary for the functioning of healthy tissues and cells.
- Immune function – Iron is important for limiting pathogens and mounting immune responses.
- Growth – Iron is involved in the regulation of cell cycles and growth, and thus, is necessary in periods of growth, such as infancy, childhood, pregnancy, training and more.
- Metabolism – Furthermore, iron is involved in carbohydrate metabolism, so iron for runners is obviously monumental. Too much or not enough iron will have an impact on energy production in the body.
Training and Iron Status
Here’s how it works: Your lungs take in oxygen and that oxygen enters the bloodstream. The hemoglobin in your blood takes that oxygen to all the different parts of your body.
Therefore, low iron levels can lead to reduced production of red blood cells and hemoglobin, otherwise known as anemia. Anemia in athletes can be common.
When you train, you improve your ability to consume oxygen more efficiently. But if you are low in iron, and your hemoglobin levels are low, your training and performance will be hindered at or after a certain point.
In short, both oxygen transport and glucose metabolism are paramount for runners.
Your muscles need both oxygen and glucose to perform their best.
Iron for Other Athletes
Runners aren’t the only ones who need adequate iron levels.
Some nutrients compete for absorption. For example, Since iron and calcium compete for absorption, you should avoid high-calcium and high-iron foods in the same meals.
As previously mentioned, phytates inhibit the absorption of both iron and zinc.
While this information is meant to be informative and not diagnostic criteria, you can learn more about the best supplements for runners to see how to distinguish between third-party verified and top quality brands.
Always consult with your individual care provider before taking any sort of supplement.
How Much Iron Do Runners Need?
Runners aren’t the only ones who need iron.
Women typically need 18mg of iron per day, while the RDA (recommended daily intake) for men is 8 mg. These needs increase during pregnancy, during heavy training sessions, and for those with heavy periods.
Some research indicates that vegetarians and vegan athletes should take in more iron since it is less bioavailable (not as optimally absorbed).
Of course, iron is important for everyone, but there is a higher demand in all athletes, and low iron in athletes is a problem.
- For example, this study showed that ball players (soccer and basketball) had lower iron levels than that of their normal peers.
- It’s not just the pros we’re worried about. Even those who are recreationally active had a higher prevalence of low iron levels.
So, why is it that athletes seem to have lower iron levels?
Here are some things that can impact iron for runners.
It’s been found that hepcidin, a hormone that helps regulate iron, peaks about 3-6 hours after exercise.
Hepcidin decreases iron absorption. Researchers have concluded that this peak is likely a major contributor to iron deficiency in athletes.
B. Inflammation and Mineral Loss
Another factor potentially impacting the amount of iron absorbed by the body is something known as exercise-induced inflammation. Additionally, the body loses iron through sweat.
C. Restrictive Diets
And in some sports, diets may be restrictive. For example, a female athlete diet should be different than a male counterpart’s because women have different hormones, nutrition needs, hydration needs and more.
Relative energy deficiency in sport, something known as RED-S, can be a major problem when undereating, over-exercising, or a combination of the two. It isn’t even necessarily intentional, but it can be when linked to eating disorders and disordered eating habits.
The reduced iron absorption and increased iron losses need to be made up through the intake of iron, whether that be through foods, supplements, or other measures as prescribed by your doctor.
Female vs. Male Iron Needs and Status
There is a difference between males and females when it comes to iron levels. Women tend to be more iron deficient than males, and may struggle with higher bouts of anemia.
This 2019 research review suggests that between 15-35% of female athletes are iron deficient, compared to 5-11% of male athletes.
There are a few reasons why women, particularly female athletes, are more likely to be iron deficient than male athletes.
- blood loss during menstruation
- Undereating, diet restriction and/or restricting large food groups (this applies to both males and females)
- pregnancy and childbirth, if applicable
Because of this, female athletes need to be more diligent about getting enough iron through diet or supplementation.
The Academy of Nutrition and Dietetics Sports Nutrition Position Paper states that “iron requirements for all female athletes may be increased by up to 70% of the estimated average requirement.”
Undereating is a big one that deserves more recognition and it makes sense.
Since we only absorb about 6 mg of iron per 1,000 calories eaten, it is nearly impossible to meet your iron needs if you are restricting your calories.
Loading up on staples from the athletes grocery list can help you learn to make balanced meals.
Low Iron in Athletes: Signs and Symptoms
You may be wondering if you are suffering from low iron, and wondering what the signs or symptoms of that may look like.
While it may be specific to each individual, there are some overall umbrella symptoms to be aware of.
Also, remember that because of the reduced absorption and increased iron loss, as an athlete, you are at a greater risk for iron deficiency.
Signs of iron deficiency include:
- Cold hands and feet
- Looking pale
- Sore or tender tongue
- Rapid heartbeat
- Chest pain
- Nails easily break
- Shortness of breath
Iron Levels for Athletes- What’s Normal?
It’s important to have your iron levels checked on a regular basis to make sure you aren’t deficient. A lab draw, including a complete blood count (CBC), will measure your hemoglobin.
The normal hemoglobin range for males is 14-18 g/dL, while females is 12-16 g/dL. Besides hemoglobin levels, iron status will be measured to determine if you have iron deficiency anemia.
Labwork can also measure ferritin, the protein that stores iron in the blood.
Here are the normal iron laboratory levels:
Dietary Sources of Iron
The best way to prevent iron deficiency is to eat adequate iron through your diet.
There are 2 forms of iron found in food—heme and non-heme iron.
Heme iron is the most easily absorbable form of dietary iron (15-35%), and are found in the following foods:
- Red meat
- Clams and oysters
- Gamey meats, like venison or elk
- Organ meats
Heme iron contributes 10% or more of our total absorbed iron.
Non Heme Iron Sources
Don’t worry – there are many plant-based sources that contribute non-heme iron.
- Eggs (particularly the yolk) – Lots of benefits of eggs for runners!
- Nuts and seeds
- Whole grains, like whole grain pasta
- Fortified foods
To optimize iron absorption from food, pair your iron sources with foods rich in vitamin C, like fruits or vegetables.
For instance, throw some peppers or broccoli in with your beans or beef stir-fry to improve iron uptake.
Fruits like oranges, berries, mango, pineapple, and kiwi, can also be eaten alongside meals to boost iron absorption.
What Impacts Iron Absorption?
There are a few nutrients that play a role in the amount of iron absorption in the intestines.
- Calcium – Too much calcium can interfere with the absorption of iron. Therefore, you may want to save your glass of milk for snack time if your meal is iron-rich to prevent absorption competition.
- Phytates – Phytate, or phytic acid, is a naturally occurring compound found in plant foods, like whole grains, seeds and legumes. However, soaking beans and legumes overnight can reduce their phytate content.
- Oxalic Acid – There are some reports that oxalic acid, found in greens, coffee, beans and nuts, may decrease iron absorption.
Sample Iron Rich Meal Plan for Vegetarian Athlete
Here is an example of a day of eating for a vegetarian athletes who includes seafood and eggs.
Note: calorie and energy needs will vary for different athletes and stages of training, this is just an example.
Breakfast: 1 cup breakfast cereal, fortified with 25% iron with 6-8 ounces soy milk/yogurt + 2 eggs and 1 cup orange juice = 8-10 mg of iron
Post Workout Snack: 1 ounce cashews (~18 nuts) + 1 orange + 1 cup soy milk = 2-4 mg of iron.
* Vitamin C from the orange will help improve absorption of the iron in the cashews
Lunch: 1/2 cup cooked lentils and 1 cup cooked rice and leafy green salad with 2 pieces of bread and 1/4 avocado = 8-10 mg of iron
Pm Snack: Tortilla with 1 banana + 1 T peanut butter + 2 T hemp seeds = 2-3 mg iron
Dinner: 6 oz salmon with 1 cup green peas + 1 baked potato with 1 T vegan butter = 4-5 mg
Total Iron: 24-32 mg iron
Check out these vegetarian meals for athletes for more ideas.
Iron Supplements for Runners
Should all runners be supplementing with iron?
You should always consult with your healthcare provider before starting a supplementation regimen.
Remember, this post is meant for informational purposes only and is not for diagnosing or treatment.
A 2023 study indicated that routinely supplementing with a low dose (3.6 mg/day) of iron was beneficial for non-anemic endurance athletes.
Those who supplemented with iron had improved stress and mood, and less fatigue. And mood isn’t all. This review found supplementation with oral iron helpful in improving performance, as well.
On the other hand, iron supplementation is not recommended if you don’t have low ferritin levels. Supplementing athletes with ferritin levels <20 μg/L may be more beneficial than supplementing athletes with higher baseline ferritin levels.
Always consult with your physician first before taking an iron supplement.
Best Iron Supplements for Runners
What iron supplement should you take?
- Ferrous sulfate – Ferrous sulfate is often a top choice for supplementation. It is the most commonly used iron in studies. And it’s easy to find and the most affordable. This form is well absorbed but may cause some stomach upset or constipation.
- Ferrous gluconate – Ferrous gluconate is a good option if you are having GI trouble with a ferrous sulfate supplement. Because it’s slightly lower in elemental iron, it’s less likely to cause stomach upset. However, ferrous gluconate is typically more expensive than ferrous sulfate.
- Ferrous fumarate – This form has the highest percentage of elemental iron but isn’t quite as bioavailable as ferrous sulfate. That said, it can be an effective treatment for anemia. Again, because of the elemental iron, it may cause GI upset and adverse effects.
A best practice for supplements is to avoid taking with things that interfere with absorption, like milk or coffee, high-fiber foods, or antacids.
Because calcium interferes, don’t take your iron supplement at the same time as a calcium supplement.
When Should You Take an Iron Supplement?
Iron absorption is impacted by exercise and hormones released during and after. Hepcidin, an iron regulatory hormone, peaks after exercise and decreases iron absorption.
So, it would be best to take iron before your run, rather than after.
You want to take your iron supplement at least 30 minutes before eating to improve absorption.
Key Takeaways of Iron for Athletes
- Iron is a nutrient that is essential for the transport of oxygen in the blood. It also plays a role in carbohydrate metabolism—crucial for energizing athletes and non-athletes alike.
- Iron deficiency can impact athletic performance.
- All athletes, including runners, are at risk for iron deficiency due to absorption issues and losses through sweat.
- Women are at a higher risk for iron deficiency.
- There are physical signs and symptoms of low iron levels, like fatigue and weakness. As an athlete, it’s recommended you have your iron levels checked periodically, especially if experiencing symptoms.
- You can get iron through your diet and by supplementation.
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