What illness depletes iron? A comprehensive guide to causes and conditions

September 30, 2025 •

4 min read

According to the World Health Organization, iron deficiency is the most common nutritional deficiency worldwide, and it can affect people of all ages. While diet is a factor, an underlying illness often explains what illness depletes iron and leads to a significant deficit. This can occur through three primary mechanisms: chronic blood loss, impaired absorption, or inflammation.

Quick Summary

Iron deficiency stems from illnesses causing chronic blood loss, impaired iron absorption in the gut, or chronic inflammation that disrupts iron metabolism. Conditions range from gastrointestinal disorders like celiac disease to autoimmune disorders, chronic kidney disease, and heavy menstrual bleeding.

Key Points

Blood Loss is a Major Culprit: Conditions causing chronic, low-grade bleeding, like gastrointestinal ulcers or heavy menstrual periods, are common reasons for iron depletion.
GI Disorders Impair Absorption: Diseases such as celiac disease and Crohn's damage the intestinal lining, preventing the effective absorption of iron from food.
Inflammation Blocks Iron Use: Anemia of chronic disease, driven by inflammatory conditions like rheumatoid arthritis or kidney disease, traps iron in the body's storage cells, making it inaccessible.
Diagnosis is Key: Relying solely on iron supplements is not a fix; a medical professional must diagnose and treat the underlying illness to properly restore iron levels.
Symptoms Require Attention: If you experience persistent fatigue, pale skin, or shortness of breath, consult a doctor to investigate potential underlying causes beyond diet.
Medication and Surgery Play a Role: Long-term use of NSAIDs can cause GI bleeding, while certain surgeries, like gastric bypass, can impact the body's ability to absorb iron.
CKD Affects Iron in Multiple Ways: Chronic kidney disease uniquely affects iron levels by causing inflammation and reducing erythropoietin, a hormone needed for red blood cell production.

The Major Pathways to Iron Depletion

Understanding how different diseases impact the body's iron supply requires a look at the three main pathways. Many conditions, in fact, involve a combination of these mechanisms, making diagnosis complex.

Chronic Blood Loss: The Hidden Culprit

This is the most common cause of iron deficiency in adults and can often go unnoticed. When you lose blood, you also lose iron-rich hemoglobin. If the blood loss is persistent but slow, the body's iron stores can become critically low over time without visible signs of bleeding.

Common causes of chronic blood loss include:

Gastrointestinal (GI) Bleeding: This is a major concern, particularly in men and postmenopausal women, and can be caused by conditions like peptic ulcers, gastritis, inflammatory bowel disease (IBD), and GI cancers,. The long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen is also a frequent cause of GI bleeding.
Heavy Menstrual Periods (Menorrhagia): Women who experience heavy, long, or frequent periods are at a high risk of developing iron deficiency because they lose more blood than their body can replace.
Frequent Blood Donation: Regular blood donors may deplete their iron stores faster than they can be replenished through diet alone.

Impaired Iron Absorption (Malabsorption)

The majority of iron is absorbed in the small intestine, specifically the duodenum. Certain diseases can damage or alter this part of the gut, preventing the body from properly absorbing iron from food and supplements, even with a sufficient dietary intake.

Conditions leading to malabsorption include:

Celiac Disease: An autoimmune disease triggered by gluten, it causes damage to the lining of the small intestine, leading to malabsorption of iron and other nutrients. Even after adopting a gluten-free diet, some individuals may have persistent issues.
Inflammatory Bowel Disease (IBD): Chronic inflammation from conditions like Crohn's disease and ulcerative colitis can impair the intestine's ability to absorb iron.
Gastric Bypass Surgery: Procedures that bypass parts of the small intestine can significantly reduce the area where iron is absorbed.
Helicobacter pylori (H. pylori) Infection: This bacteria can cause chronic gastritis, leading to decreased stomach acid and inflammation that interferes with iron absorption.

Anemia of Chronic Disease (Inflammation)

Anemia of inflammation, also known as anemia of chronic disease (ACD), is the second most common type of anemia after iron deficiency anemia. In this scenario, the body has sufficient or even high iron stores, but the chronic inflammation prevents the body from using this iron effectively to produce red blood cells. This is mediated by an increase in the hormone hepcidin, which blocks the release of iron from storage cells.

Diseases that cause chronic inflammation include:

Chronic Kidney Disease (CKD): Patients with CKD often develop anemia for multiple reasons, including reduced production of erythropoietin (a hormone that stimulates red blood cell production) and inflammation that contributes to ACD,. Blood loss during dialysis can also exacerbate the problem.
Autoimmune Diseases: Conditions like rheumatoid arthritis and lupus cause persistent inflammation that can trigger ACD.
Cancer: Malignancies can lead to anemia through multiple pathways, including inflammation, blood loss, and effects on the bone marrow.
Congestive Heart Failure: This condition involves chronic inflammation that can disrupt iron regulation.

Iron Depletion Mechanisms: A Comparison Table


Feature	Chronic Blood Loss	Impaired Absorption	Anemia of Chronic Disease (Inflammation)
Underlying Problem	Loss of iron from the body due to bleeding	Inability to absorb iron from the diet	Inability to use stored iron effectively
Mechanism	Mechanical loss of red blood cells and their iron content	Damage to the small intestine, blocking iron uptake	Release of inflammatory signals (hepcidin) that block iron from being released from stores
Examples of Illnesses	Heavy menstruation, GI ulcers, colorectal cancer, regular NSAID use	Celiac disease, Crohn's disease, gastric bypass surgery, H. pylori infection	Chronic Kidney Disease, Rheumatoid Arthritis, Cancer, Lupus, Congestive Heart Failure
Iron Stores (Ferritin)	Typically low to very low	Low, as the body struggles to replenish stores	May appear normal or even high, which can be misleading
Treatment Focus	Stopping the source of bleeding and iron replacement	Addressing the underlying GI condition and iron replacement	Treating the underlying chronic condition, with iron supplementation and erythropoiesis-stimulating agents as needed

The Importance of Diagnosis

If you experience symptoms of iron deficiency—such as fatigue, pale skin, shortness of breath, or cold hands and feet—it is crucial to seek a medical diagnosis. Unlike simply taking iron supplements for a dietary deficiency, treating an underlying illness is essential for long-term recovery and preventing recurrence. A healthcare provider will typically order a complete blood count (CBC) and check iron levels, including ferritin, to determine the nature of the deficiency. Depending on the results, further investigation, such as an endoscopy, may be necessary to find the root cause.

Conclusion

Numerous illnesses, from gastrointestinal disorders that cause chronic blood loss or malabsorption to chronic inflammatory diseases that disrupt the body's iron regulation, can significantly deplete iron stores. For these conditions, simply addressing dietary intake is not enough. Proper diagnosis and treatment of the underlying medical issue are essential to effectively restore iron levels and alleviate symptoms. By understanding what illness depletes iron, patients can take informed steps toward recovery with their healthcare team.(https://www.nhlbi.nih.gov/health/anemia/iron-deficiency-anemia)

Frequently Asked Questions

Gastrointestinal conditions can deplete iron in two main ways: through chronic, slow blood loss from issues like ulcers, or through malabsorption where the intestine is too damaged to absorb iron properly, as is the case with celiac or Crohn's disease,.

Chronic inflammation, often from autoimmune diseases or long-term infections, causes the body to produce high levels of a hormone called hepcidin. Hepcidin blocks the body from releasing iron from its storage cells, making it unavailable for red blood cell production.

Yes, chronic kidney disease can cause iron deficiency and anemia in multiple ways. The kidneys may not produce enough erythropoietin, and inflammation associated with the disease can lead to functional iron deficiency. Patients on dialysis may also experience blood loss.

Heavy menstrual bleeding, or menorrhagia, is a condition that, while natural, can lead to significant and chronic blood loss, directly causing iron deficiency. It is a very common cause, especially in premenopausal women.

While a gluten-free diet helps heal the small intestine, some individuals with celiac disease may still have persistent issues with malabsorption due to long-term damage or other factors. This can make oral iron supplementation ineffective and necessitate periodic intravenous iron.

Absolute iron deficiency means the body's total iron stores are depleted, often from blood loss or malabsorption. Functional iron deficiency, seen in chronic disease, means there is stored iron, but inflammation prevents the body from using it effectively for red blood cell production.

Beyond a standard complete blood count (CBC) and ferritin test, a doctor may perform additional investigations depending on your symptoms. These can include tests for occult blood in the stool, endoscopy or colonoscopy to check for GI bleeding, and checks for markers of inflammation,.