Iron Deficiency in Athletes

Introduction:

Athletes intake a high quantity of carbohydrates, proteins, and fat but fail to add essential micronutrients like iron to their diet. Iron deficiency may affect athletes’ performance. Iron is essential for growth and development. The body uses iron to make hemoglobin (a protein that carries oxygen to the tissues) and myoglobin (a protein that carries oxygen to the muscles).

What Are the Key Roles of Iron?

• Helps in energy metabolism.

• Helps in delivering oxygen to tissues and muscles.

• It supports immunity.

• Helps to fight against stress.

• Helps to synthesize hormones.

Where Is Iron Stored in the Human Body?

The adult human body contains three to four grams of iron. Most of the iron is in hemoglobin; the rest is in the spleen, liver, bone marrow, and muscles.

What Is Sports Anemia?

Athletes have lower hemoglobin levels than general people, called sports anemia or false anemia. Iron deficiency occurs when the body does not have enough iron required to make hemoglobin. This leads to a lack of oxygen supply to tissues and muscles. Poor iron status results in higher blood lactate concentrations during exercise.

What Are the Severity Levels of Iron Deficiency?

• Storage Iron Depletion: Functioning iron is intact, while storage iron is depleted. This will not affect athletic performance.

• Early Functional Iron Deficiency: Hemoglobin levels are normal. There is low serum ferritin and impaired red blood cell count production.

• Iron Deficiency Anemia: Hemoglobin level is reduced and causes fatigue and reduced ability to work. They are common in athletes and regular exercises.

What Are the Causes and Symptoms of Anemia?

• Fatigue.

• Weakness.

• Pale skin.

• Shortness of breath.

• Lightheadedness.

Why Does Iron Deficiency Occur?

The main mechanism that leads to iron deficiency are:

• Increase in iron demand.

• Increase in iron loss.

• Blockage in iron absorption.

What Are the Factors That Influence Iron Metabolism?

1. Iron Absorption: The iron in the intestine is absorbed by its bioavailability. The factors that affect iron absorption are a vegetarian diet and a diet plan without carbohydrates for a longer period, especially for athletes, to increase their performance level. Ascorbic acid helps in iron absorption. The bioavailability of iron should be higher than that of ingested iron. Thus it is important to decrease the factors that reduce its absorption and to increase those factors that help in the absorption of iron.

2. Iron Loss During Exercise: It occurs through sweating, hematuria (presence of blood in urine), abdominal bleeding, inflammation, and hemolysis (breakdown of red blood cells). Sweating is the outcome of physical activity, and it is involved in thermoregulation. Sweating causes loss of iron up to 2.5 micrograms of iron/liter of sweat. Hematuria (presence of blood in urine) is seen in runners due to repeated contact of the wall of the bladder with its neck during running. This leads to hypoxia (absence of oxygen to tissues), lactate accumulation, stress, and hormonal imbalance and indicates acute kidney injury in runners.

3. Gastrointestinal Diseases: Gastrointestinal disease in athletes causes digestive blood loss. Physical exercise prevents and reduces disease progression. Exercise also decreases stress and anxiety. However, strenuous activity induces intestinal injury and slows down gastric and intestinal motility, and leads to malabsorption. The exercise-induced gastrointestinal syndrome occurs due to the following reasons:

• Redistribution of blood from the gastrointestinal tract to the working muscles.

• Physical activity increases sympathetic activity, which reduces nervous system functions.

Causes:

• Malabsorption.

• Fecal blood loss.

• Alteration in gut microflora.

• Systemic inflammation.

Prevention:

• Maintaining hydration during exercise.

• Consumption of carbohydrates.

• Pre-exercise dietary adaptation.

• Including a gluten-free diet.

• Avoiding painkillers.

• Using dietary antioxidant supplements.

1. Inflammation: Regardless of the type and intensity of the exercise, interleukin-6 increases after physical activity and increases the chances of inflammation. The increased interleukin-6 causes hepcidin elevation and thus lowers iron absorption. Hepcidin is increased in individuals with inflammatory anemia. Pre-exercise iron status and hypoxia (absence of oxygen to tissues) are the regulators of hepcidin. These suppress the hepcidin activity and increase the bioavailability.

2. Other Loses: Other losses include heavy menstrual bleeding in female athletes, which impacts the athletes' performance. Oral contraceptives are used to control menstrual cycle bleeding. They increase the oxidative stress biomarkers and c-reactive proteins that regulate the menstrual flow.

What Is Sports-Related Hemolytic Anemia?

Exercise-induced hemolytic anemia is the rupture and disruption of red blood cells during exercise. It most commonly occurs in runners and swimmers.

Causes:

• Mechanical injury- forceful ground contact.

• Repeated muscle contraction.

• Vasoconstriction.

• Metabolic disturbances like hyperthermia (rise in temperature), dehydration, hypoxia (impaired oxygen supply to tissues), shear stress, and oxidative damage.

Prevention:

• The urine dipstick test helps to identify acute kidney injury.

• Continuous cycling with low intensity.

What Are the Other Considerations?

• Evaluating athletes’ iron status- including diet, sex hormones, environmental stress, and types of exercise.

• Exercise training at high altitudes increases adaptation to hypoxia- improvement has been taken to change to sea level performance.

• Extra iron intake is necessary for high-altitude training.

• Altitude training iron requirements- 100-200 milligrams of elemental iron per day.

Why Are Athletes at Risk of Iron Deficiency?

Athletes exercise regularly and lose iron through sweat, skin, urine, and menstruation. Also, the body is not very effective at absorbing dietary iron.

Who Is at Risk of Iron Deficient Anemia Among Athletes?

• Female athletes.

• Vegetarian athletes or athletes who restrict iron-rich foods in their diet.

• Underweight or undernourished athletes.

• Endurance athletes.

What Are Iron-Rich Foods?

• Dark meat.

• Beans, lentils, nuts, and sunflower seeds.

• Iron-fortified cereals- cold cereals and oatmeal.

• Green leafy vegetables- spinach and broccoli.

• Dried fruits- raisins, apricots, and prunes.

What Are the Ways to Improve Iron Absorption?

• Animal sources of iron are absorbed better than plant sources.

• Intake of more citrus fruit or orange juice as vitamin C enhances iron absorption.

• Intake of more vitamin C foods such as red pepper, grapefruit, broccoli, and strawberries.

• Should avoid tea, coffee, and cocoa products.

Conclusion:

If the iron level is not increased through diet or taking a multivitamin, it is important to consult a physician and start with iron supplements. Iron supplements have side effects like constipation, nausea, stomach pain, and organ damage. Athletes who are at high-risk should check their iron levels annually.