In athletes, reduced iron levels are a common condition that can impair energy, oxygenation, and performance. This article examines the causes, symptoms, and consequences of iron deficiency in athletes, with a focus on nutritional strategies, targeted supplementation, and the unique needs of individuals following vegetarian or vegan diets.

Iron needs in athletes

Among the most recommended and widely used supplements in sports, iron holds a prominent place. But why is it so important?

Iron is an essential micronutrient for the optimal functioning of an athlete's body, playing a crucial role in various vital functions, including energy metabolism, oxygen transport, cognitive function, and immune response.

In particular, iron is vital for the formation of hemoglobin, a protein in red blood cells that binds oxygen in the lungs and delivers it to body tissues, allowing cells to use it to produce energy.

Most of the body’s iron is found in circulating red blood cell hemoglobin, with smaller amounts stored in ferritin and myoglobin—proteins responsible for iron storage and oxygen transport in muscles.

Since the human body cannot produce iron, it must be obtained through diet or supplements when necessary.

Recommended daily iron intake is 10 mg for adult men and 18 mg for women of childbearing age, according to the Italian LARN (Reference Intake Levels of Nutrients and Energy for the Italian population).

Athletes are especially vulnerable to iron deficiency due to the increased demand induced by intense and prolonged exercise.

Aerobic exercise, in particular, increases iron requirements to support hemoglobin production and ensure proper oxygen delivery to skeletal muscles.

Endurance athletes such as runners or cyclists may require more iron to compensate for red blood cell breakdown and increased oxygen demand during exercise.

Groups at greater risk of deficiency include:

1. Female athletes of childbearing age, due to iron loss during menstruation

2. Endurance athletes training at altitude, where hypoxia stimulates red blood cell production and increases iron needs

3. Vegetarian and vegan athletes, as plant-based iron is less bioavailable than animal-based sources

4. Athletes with low energy availability, which can impair the ability to maintain adequate iron stores.

Iron deficiency, or sideropenia, can negatively impact health and performance, leading to:

1. Reduced oxygen transport capacity

2. Decreased energy production

3. Increased fatigue and tiredness

4. Weakened immune response

Treating iron deficiency

Managing iron deficiency in athletes requires medical supervision and an integrated approach, including periodic blood tests and early detection of reduced iron stores.

With the summer season and altitude training camps approaching, especially for amateur cyclists, it’s crucial to check iron levels 8–12 weeks beforehand to correct any deficiency and promote better physiological adaptation.

Therapeutic strategies depend on severity and clinical history, and may include dietary adjustments, oral supplementation, or intravenous treatment.

Boosting dietary iron intake is the first step when a deficiency is present.

There are two types of iron:

1. Heme iron (from animal sources like red meat, fish, poultry)

2. Non-heme iron (from plant sources like spinach, legumes, and whole grains)

The body more efficiently absorbs heme iron, but the absorption of non-heme iron can be enhanced by consuming it with vitamin C-rich foods like citrus fruits or broccoli.

If dietary intake isn’t enough, oral supplementation is the next step. This includes ferrous salts like ferrous fumarate, sulfate, or gluconate, but some athletes can poorly tolerate these.

Sucrosomial® Technology, which uses a phospholipid and sucrose ester coating, improves iron’s bioavailability and tolerability.

Supplements like Iron Race, which combine Sucrosomial® Iron (Sideral® r.m.) with other nutrients such as vitamins and minerals to support energy production and iron stores, are among the best current options.

In more severe cases—particularly when anemia is present with significantly low hemoglobin—intravenous iron therapy may be necessary, under the care of a sports physician.

Improving iron absorption

Iron absorption is enhanced when taken with a source of vitamin C, either within the supplement or alongside citrus juice like orange or grapefruit.

It’s also important to avoid iron absorption inhibitors around the time of intake. These include:

1. Calcium, found in dairy products like milk, yogurt, and cheese

2. Tannins, found in tea and coffee

Avoid these foods about one hour before and after taking iron.

Iron absorption (from food or supplements) can be influenced by two main groups of compounds:

1. Inhibitors of iron absorption, such as:

- Phytates (whole grains, legumes, nuts, seeds)

- Polyphenols (tea, coffee, red wine, chocolate)

- Calcium (dairy products, multivitamins)

- Other minerals like zinc and manganese (which compete with iron for absorption).

2. Promoters of iron absorption like:

- Vitamin C (citrus, broccoli, tomatoes, peppers)

- Carotenoids (pumpkin, carrots, grapefruit, apricots)

- Fermented foods (sauerkraut, kimchi, miso)

- Cooking (which reduces phytate content).

Risks of iron supplementation in athletes

Sideropenia treatment requires a holistic approach to avoid complications from improper supplementation.

1. Identifying and treating underlying causes: Iron supplements don’t address dietary deficiencies or root causes. It is essential to provide specialized dietary counseling through a sports dietitian to tackle nutritional deficiencies.

2. Iron overload and medical risks: Excessive iron intake can lead to overload, a potentially dangerous condition for athletes. Individuals with hemochromatosis should avoid supplementation, as high iron levels can be toxic to organs.

3. Administration risks: IV or intramuscular iron may cause serious side effects such as anaphylactic shock or injection-related complications.

4. Gastrointestinal side effects: Some oral iron forms can cause issues like gastrointestinal discomfort, such as constipation. Alternative supplementation strategies, such as alternate-day dosing, can help mitigate these side effects without compromising long-term treatment efficacy (8–12 weeks).

Conclusions

Iron is a key element for athlete health and performance, but it must be managed carefully.

Regular monitoring, targeted nutrition, and well-tolerated supplementation—like Sucrosomial® Iron—can significantly impact energy, performance adaptation, and recovery.

Addressing a deficiency is not just about filling a gap: it requires knowledge, expertise, and a tailored plan, always guided by qualified professionals.

Bibliography

Gómez-Ramírez S, Brilli E, Tarantino G, Muñoz M. Sucrosomial® Iron: A New Generation Iron for Improving Oral Supplementation. Pharmaceuticals (Basel). 2018 Oct 4;11(4):97.

Sim M, Garvican-Lewis LA, Cox GR, Govus A, McKay AKA, Stellingwerff T, Peeling P. Iron considerations for the athlete: a narrative review. Eur J Appl Physiol. 2019 Jul;119(7):1463-1478.

Stellingwerff T, Peeling P, Garvican-Lewis LA, Hall R, Koivisto AE, Heikura IA, Burke LM. Nutrition and Altitude: Strategies to Enhance Adaptation, Improve Performance and Maintain Health: A Narrative Review. Sports Med. 2019 Dec;49(Suppl 2):169-184.

Article by Dr. Alessandro Bonuccelli – Sports and Clinical Dietitian