Primary Keyword: Iron Deficiency

Secondary Keywords

• Iron Deficiency Symptoms
• Low Iron
• Low Ferritin
• Ferritin Levels
• Anaemia
• Fatigue
• Personalised Medicine
• Lifestyle Medicine
  
  

Introduction

Iron deficiency is one of the most common nutritional deficiencies worldwide, affecting millions of people across all age groups.

Although it is often associated with anaemia, iron deficiency can exist long before anaemia develops. During these early stages, individuals may experience symptoms such as fatigue, reduced exercise tolerance, poor concentration or decreased physical performance despite having normal haemoglobin levels.

Because these symptoms are non-specific, iron deficiency frequently goes unrecognised or is attributed to stress, ageing or a busy lifestyle.

However, identifying iron deficiency early is important not only for relieving symptoms but also for understanding why iron stores have become depleted.

In some individuals, low iron simply reflects increased physiological demands or insufficient dietary intake.

In others, it may indicate chronic blood loss, impaired intestinal absorption or an underlying medical condition requiring further investigation.

For this reason, modern medicine focuses on identifying the cause of iron deficiency rather than simply replacing iron.

Throughout this article, we explain the role of iron in the body, the causes and symptoms of iron deficiency, how it is diagnosed and why a personalised medical assessment is essential for selecting the most appropriate treatment.

What Is Iron?

Iron is an essential mineral that plays a fundamental role in many physiological processes.

Its best-known function is its contribution to the production of haemoglobin, the protein inside red blood cells responsible for transporting oxygen from the lungs to tissues throughout the body.

Without sufficient iron, oxygen delivery becomes less efficient, potentially leading to reduced energy levels and impaired physical performance.

However, iron has many other important functions beyond haemoglobin production.

Iron contributes to:

• Oxygen transport.
• Energy production within cells.
• Normal muscle function.
• Cognitive performance.
• Immune system function.
• DNA synthesis.
• Cellular growth and repair.

Because these processes occur throughout the body, iron deficiency may affect multiple organ systems and produce a wide variety of symptoms.

Why Is Iron Essential?

Every cell in the body depends on oxygen to produce energy.

Iron is central to this process because it allows haemoglobin to bind oxygen in the lungs and release it to tissues where it is needed.

Iron is also present in myoglobin, a protein found in muscles that stores and delivers oxygen during physical activity.

In addition, iron supports numerous enzymes involved in cellular metabolism and mitochondrial energy production.

When iron stores become depleted, the body gradually adapts by prioritising essential functions.

Initially, iron deficiency may cause only subtle symptoms.

If deficiency progresses, red blood cell production becomes impaired, eventually leading to iron deficiency anaemia.

This gradual progression explains why many people experience fatigue or reduced exercise capacity before anaemia is detected.

Iron vs Ferritin: What Is the Difference?

Many people assume that iron and ferritin are the same thing.

In reality, they measure different aspects of iron metabolism.

Iron refers to the amount of circulating iron available in the bloodstream at a particular moment.

These levels naturally fluctuate throughout the day and are influenced by recent food intake and other physiological factors.

Ferritin, by contrast, is a protein that stores iron inside cells.

Blood ferritin levels provide a useful estimate of the body's iron reserves.

For this reason, ferritin is often considered one of the most informative laboratory markers when assessing iron deficiency.

In many individuals, ferritin levels begin to fall before haemoglobin becomes abnormal.

This means a person may have depleted iron stores and experience symptoms even though they have not yet developed anaemia.

Interpreting iron studies therefore requires looking at the complete clinical picture rather than relying on a single laboratory value.

Who Is Most at Risk of Iron Deficiency?

Although iron deficiency can affect anyone, certain groups have a substantially higher risk.

Women of Reproductive Age

Menstrual blood loss is one of the most common causes of iron deficiency worldwide.

Women with heavy menstrual bleeding are particularly vulnerable to depleted iron stores.

Pregnancy

During pregnancy, iron requirements increase significantly to support maternal blood volume expansion and fetal development.

Adequate monitoring and appropriate supplementation may be recommended when clinically indicated.

Children and Adolescents

Periods of rapid growth increase iron requirements.

If dietary intake does not meet these increased demands, deficiency may develop.

Endurance Athletes

Long-distance runners, cyclists and other endurance athletes may have increased iron requirements due to repeated physical stress, minor gastrointestinal blood loss and increased red blood cell turnover.

Vegetarians and Vegans

Plant-based diets can provide iron, but the non-haem iron found in plant foods is generally absorbed less efficiently than the haem iron found in animal products.

A well-planned vegetarian or vegan diet can still meet iron requirements, but careful dietary planning is important.

People with Gastrointestinal Disorders

Conditions affecting the digestive tract may reduce iron absorption or cause chronic blood loss.

Examples include:

• Coeliac disease.
• Inflammatory bowel disease.
• Peptic ulcer disease.
• Previous gastrointestinal surgery.
  
  

Why Is Iron Deficiency So Common?

Iron deficiency develops when iron losses or requirements exceed iron intake and absorption over time.

This imbalance may result from one or several contributing factors.

Common causes include:

• Heavy menstrual bleeding.
• Pregnancy.
• Inadequate dietary intake.
• Reduced intestinal absorption.
• Chronic gastrointestinal bleeding.
• Frequent blood donation.
• Increased athletic demands.
• Certain chronic medical conditions.

Because the causes vary considerably between individuals, simply replacing iron without investigating the underlying reason may fail to address the problem completely.

This illustrates one of the core principles of personalised medicine:

Successful treatment begins with understanding the cause—not simply correcting the laboratory value.

Common Symptoms of Iron Deficiency

Iron deficiency often develops gradually.

In the early stages, the body's iron stores begin to decline while haemoglobin levels may still remain within the normal range.

As a result, many individuals experience symptoms long before iron deficiency anaemia develops.

The severity of symptoms varies considerably from one person to another and does not always correlate perfectly with laboratory values.

Common symptoms include:

• Persistent fatigue.
• Reduced energy.
• Weakness.
• Shortness of breath during physical activity.
• Reduced exercise tolerance.
• Difficulty concentrating.
• Brain fog.
• Headaches.
• Dizziness.
• Pale skin.
• Cold hands and feet.

Because these symptoms are common to many medical conditions, iron deficiency should always be considered alongside other possible causes rather than assumed to be the sole explanation.

Iron Deficiency Without Anaemia

One of the most important concepts in modern medicine is that iron deficiency may exist even when haemoglobin levels remain normal.

This stage is often referred to as iron deficiency without anaemia.

During this period, the body's iron stores become depleted before red blood cell production is significantly affected.

Some individuals may already experience symptoms such as:

• Fatigue.
• Poor physical performance.
• Difficulty concentrating.
• Reduced endurance.
• Decreased exercise recovery.
• Restless legs in some individuals.

Research suggests that certain patients with documented iron deficiency but normal haemoglobin may still benefit from identifying and treating the underlying deficiency when clinically appropriate.

However, treatment decisions should always be individualised and based on careful medical assessment rather than laboratory values alone.

Iron Deficiency Anaemia

If iron deficiency continues untreated, iron stores eventually become insufficient to support normal red blood cell production.

This results in iron deficiency anaemia.

Without adequate haemoglobin, oxygen delivery throughout the body becomes less efficient.

Common symptoms may include:

• Marked fatigue.
• Significant weakness.
• Shortness of breath.
• Rapid heartbeat.
• Palpitations.
• Reduced exercise capacity.
• Dizziness.
• Pale skin.

In more severe cases, everyday activities such as climbing stairs or walking moderate distances may become increasingly difficult.

Fortunately, when identified early and managed appropriately, iron deficiency anaemia is often highly treatable.

How Is Iron Deficiency Diagnosed?

Diagnosis begins with a detailed medical history and physical examination.

Rather than relying on a single laboratory value, physicians consider the patient's overall clinical picture.

Important aspects of assessment include:

• Current symptoms.
• Duration of symptoms.
• Menstrual history where appropriate.
• Dietary habits.
• Gastrointestinal symptoms.
• Medical history.
• Current medications.
• Family history.
• Previous blood test results.
• Risk factors for blood loss or impaired absorption.

This information helps determine both the likelihood of iron deficiency and the most appropriate investigations.

Laboratory Testing

Several laboratory tests contribute to the diagnosis of iron deficiency.

Common investigations include:

• Full blood count (FBC).
• Haemoglobin.
• Ferritin.
• Serum iron.
• Transferrin saturation.
• Total iron-binding capacity (TIBC).
• Mean corpuscular volume (MCV).

Depending on the clinical situation, additional investigations may also be appropriate, including:

• Vitamin B12.
• Folate.
• C-reactive protein (CRP).
• Kidney function.
• Coeliac disease screening.
• Stool testing for occult blood in selected patients.

Because ferritin is also an acute-phase protein that increases during inflammation, interpreting ferritin levels may sometimes require consideration of inflammatory markers and the patient's broader clinical context.

What Does Current Scientific Evidence Say?

Current international guidelines recommend that iron deficiency should not simply be treated as an isolated laboratory abnormality.

Instead, physicians should identify why iron deficiency has developed.

Evidence consistently supports investigating potential causes such as:

• Menstrual blood loss.
• Gastrointestinal bleeding.
• Malabsorption disorders.
• Increased physiological requirements.
• Nutritional factors.

Current evidence also recognises that iron deficiency without anaemia may produce clinically relevant symptoms in some individuals.

For this reason, diagnosis combines:

• Clinical symptoms.
• Medical history.
• Physical examination.
• Laboratory investigations.
• Assessment of underlying causes.

This personalised approach allows treatment to address both the deficiency itself and the reason it developed.

Common Myths About Iron Deficiency

Iron deficiency is one of the most misunderstood nutritional disorders.

Several misconceptions may delay diagnosis or lead to inappropriate supplementation.

Myth 1: Only women develop iron deficiency.

False.

Although women of reproductive age are at increased risk, iron deficiency also affects men, children, older adults, athletes and individuals with gastrointestinal disorders.

Myth 2: Normal haemoglobin means iron deficiency is impossible.

False.

Iron deficiency frequently develops before anaemia appears.

Many individuals have depleted iron stores despite normal haemoglobin levels.

Myth 3: Feeling tired automatically means low iron.

False.

Fatigue has many possible causes, including vitamin B12 deficiency, thyroid disorders, chronic stress, poor sleep, chronic disease and psychological factors.

Iron deficiency is only one possible explanation.

Myth 4: Everyone with low ferritin needs the same treatment.

False.

Treatment depends on:

• The severity of deficiency.
• Symptoms.
• Underlying cause.
• Medical history.
• Individual clinical circumstances.

There is no one-size-fits-all approach.

Myth 5: Taking iron supplements is always harmless.

False.

Iron supplementation should not be started solely because of fatigue or suspicion of deficiency.

Excess iron can accumulate in the body and may be harmful in certain medical conditions.

Whenever possible, supplementation should follow appropriate medical assessment and laboratory confirmation of deficiency.

How Is Iron Deficiency Treated?

The treatment of iron deficiency depends not only on restoring iron levels but also on identifying and addressing why the deficiency developed.

This is one of the fundamental principles of evidence-based medicine.

Simply replacing iron without investigating the underlying cause may allow an important medical condition to remain undiagnosed.

Treatment varies according to several factors, including:

• The severity of iron deficiency.
• Whether anaemia is present.
• The patient's symptoms.
• The underlying cause.
• Gastrointestinal absorption.
• Existing medical conditions.

For some individuals, improving dietary intake may be sufficient.

Others may require oral supplementation, intravenous iron or treatment of the underlying condition responsible for iron loss.

Oral Iron vs Intravenous Iron

One of the most common questions patients ask is whether intravenous iron is more effective than oral supplements.

The answer depends on the individual's clinical situation.

For many patients with mild to moderate iron deficiency and normal intestinal absorption, oral iron supplementation remains the first-line treatment.

However, intravenous iron may be considered in selected circumstances, including:

• Significant iron deficiency when rapid replacement is required.
• Poor tolerance of oral iron supplements.
• Inadequate response to oral treatment.
• Chronic inflammatory bowel disease.
• Significant gastrointestinal malabsorption.
• Chronic kidney disease in selected patients.
• Situations where oral iron is unlikely to be effective.

Current clinical guidelines recommend selecting the route of treatment according to the patient's clinical needs rather than assuming intravenous therapy is always superior.

Both approaches have an important role when used appropriately.

Can Diet Alone Correct Iron Deficiency?

Diet is essential for maintaining healthy iron stores, but it may not always be sufficient to correct an established deficiency.

Iron is naturally present in two forms:

Haem iron, found primarily in animal-based foods such as:

• Lean red meat.
• Poultry.
• Fish.

This form is generally absorbed more efficiently.

Non-haem iron, found in plant-based foods such as:

• Lentils.
• Chickpeas.
• Beans.
• Tofu.
• Spinach.
• Pumpkin seeds.
• Fortified cereals.

Although non-haem iron is absorbed less efficiently, a well-planned vegetarian or vegan diet can still provide adequate iron intake.

Absorption can often be improved by consuming vitamin C-rich foods alongside iron-containing meals.

However, if iron deficiency results from chronic blood loss or impaired intestinal absorption, dietary modification alone is unlikely to restore normal iron stores.

This is why identifying the underlying cause remains just as important as replacing iron itself.

Why Follow-Up Is Important

Successful treatment does not end once iron supplementation has begun.

Follow-up allows physicians to evaluate whether treatment is working as expected and whether iron stores are being adequately restored.

Depending on the individual situation, follow-up may include:

• Review of symptoms.
• Repeat haemoglobin testing.
• Ferritin measurement.
• Assessment of iron stores.
• Monitoring for side effects.
• Evaluation of the underlying cause.
• Adjustment of treatment where necessary.

Some individuals require only temporary supplementation.

Others may need longer-term monitoring if an ongoing condition continues to increase iron requirements or reduce iron absorption.

Regular follow-up helps ensure that treatment remains effective while reducing the risk of recurrence.

A Personalised Medical Approach to Iron Deficiency

Although iron deficiency is common, no two patients present in exactly the same way.

One individual may have significant fatigue despite only mildly reduced ferritin levels.

Another may have severe anaemia with surprisingly few symptoms.

Similarly, identical laboratory results may reflect completely different underlying causes.

At Dr. Indhira Ghyssaert's practice in Mallorca, every patient undergoes a comprehensive medical assessment before treatment recommendations are made.

This assessment considers:

• Current symptoms.
• Medical history.
• Dietary habits.
• Menstrual history where appropriate.
• Gastrointestinal symptoms.
• Current medications.
• Previous laboratory investigations.
• Lifestyle factors.
• Individual risk factors.

Where clinically appropriate, further investigations may be recommended to identify the underlying cause of iron deficiency and guide long-term management.

This personalised approach reflects the principles of evidence-based medicine, ensuring that treatment addresses both the deficiency itself and the reason it developed.

Frequently Asked Questions

What causes iron deficiency?

Iron deficiency may result from inadequate dietary intake, heavy menstrual bleeding, pregnancy, gastrointestinal blood loss, impaired absorption or increased physiological requirements.

Identifying the underlying cause is an essential part of treatment.

Can iron deficiency cause fatigue?

Yes.

Fatigue is one of the most common symptoms of iron deficiency because iron plays an essential role in oxygen transport and cellular energy production.

However, fatigue has many possible causes, so medical assessment is important.

Is low ferritin the same as iron deficiency?

Low ferritin usually indicates reduced iron stores and is one of the most useful laboratory markers of iron deficiency.

However, ferritin should always be interpreted alongside other blood tests, symptoms and the patient's overall clinical picture.

Are iron infusions always necessary?

No.

Many patients respond well to oral iron supplements.

Intravenous iron is generally reserved for selected clinical situations where oral treatment is ineffective, poorly tolerated or unlikely to correct the deficiency.

How long does treatment take?

Recovery varies depending on the severity of the deficiency and its underlying cause.

Many patients begin to feel more energetic within several weeks, while restoring normal iron stores often takes several months.

Regular follow-up helps monitor progress and determine the appropriate duration of treatment.

Key Takeaways

• Iron is essential for oxygen transport, energy production and normal cellular function.
• Iron deficiency may cause fatigue, poor concentration and reduced exercise tolerance, even before anaemia develops.
• Ferritin is one of the most useful markers for assessing iron stores.
• Diagnosis combines clinical assessment with appropriate laboratory investigations.
• Treatment should focus on identifying and correcting the underlying cause of deficiency.
• Oral iron remains first-line treatment for many patients, while intravenous iron has an important role in selected situations.
• Personalised medical assessment helps determine the most appropriate investigation and treatment strategy.
  
  

Conclusion

Iron deficiency is one of the most common nutritional deficiencies worldwide and a frequent cause of fatigue, reduced physical performance and impaired quality of life.

Because symptoms often develop gradually and overlap with many other medical conditions, diagnosis requires more than a single laboratory test.

Current scientific evidence supports a personalised approach in which symptoms, medical history, physical examination and laboratory investigations are interpreted together to identify both the deficiency and its underlying cause.

Whether iron deficiency results from dietary factors, increased physiological demands, chronic blood loss or impaired absorption, appropriate medical assessment allows treatment to be tailored to the individual's specific needs.

This evidence-based, patient-centred philosophy guides every consultation provided by Dr. Indhira Ghyssaert in Mallorca, where personalised medicine begins with understanding the cause of symptoms before recommending treatment.

About Dr. Indhira Ghyssaert

Dr. Indhira Ghyssaert is a physician based in Mallorca with a special interest in personalised medicine, lifestyle medicine and preventive healthcare.

Her clinical approach combines comprehensive medical assessment with current scientific evidence to develop treatment strategies tailored to each patient's individual needs, medical history and long-term health goals.

Rather than applying standardised treatment protocols, every recommendation is guided by careful clinical evaluation and evidence-based medicine.¨¨

Medical Disclaimer

The information provided in this article is intended for educational purposes only and should not replace individual medical advice.

Iron deficiency can have many different causes and should always be assessed within the context of a person's symptoms, medical history and laboratory findings. If you experience persistent fatigue, shortness of breath, dizziness or other concerning symptoms, seek assessment from a qualified healthcare professional.

Any investigations or treatment should always be based on an individual medical evaluation and current clinical evidence.