What Depletes Iron from the Body? A Comprehensive Guide

October 18, 2025 •

4 min read

According to the World Health Organization, iron deficiency is the most common nutritional deficiency worldwide, affecting over 1.6 billion people. This depletion can lead to health issues, and understanding what depletes iron from the body is crucial for effective prevention and treatment.

Quick Summary

This article explores the primary factors that cause iron depletion in the body, including chronic blood loss, dietary inhibitors, certain medical conditions, and physiological demands. It covers how different foods and medications impact iron absorption and provides actionable advice for maintaining healthy levels.

Key Points

Blood Loss is a Major Cause: Chronic blood loss from heavy menstrual periods, GI bleeding, or frequent donations is a leading factor in iron depletion.
Dietary Inhibitors Exist: Compounds in certain foods and drinks, like phytates in grains and tannins in tea, can block iron absorption, particularly non-heme iron from plants.
Certain Medical Conditions Interfere: Diseases affecting the digestive tract, such as celiac and Crohn's, or conditions causing chronic inflammation can impair iron absorption and utilization.
Medications Can Have an Impact: Acid-reducing drugs like PPIs can inhibit iron absorption, while NSAIDs can cause GI bleeding that leads to iron loss.
Increased Needs during Life Stages: Pregnancy, breastfeeding, and rapid growth spurts in children and teenagers create higher iron demands that, if not met, result in depletion.
Diagnosis is Crucial: Due to the varied causes, a proper medical diagnosis is necessary to identify the specific reason for iron depletion and create an effective treatment plan.

Introduction to Iron Depletion

Iron is an essential mineral vital for producing hemoglobin, the protein in red blood cells that carries oxygen throughout the body. The body meticulously regulates its iron stores, but various factors can disrupt this balance, leading to depletion. When iron stores drop too low, it can lead to iron deficiency anemia, a condition characterized by fatigue, weakness, and other health issues. Unlike some other nutrients, the body cannot produce iron and must absorb it from food, making diet and absorption key factors.

Chronic Blood Loss: The Primary Culprit

For many adults, especially in developed countries, the most significant cause of iron depletion is chronic blood loss.

Menstruation: Heavy or prolonged menstrual bleeding is the most common cause of iron deficiency in pre-menopausal women. The amount of blood lost each month can vary significantly, directly impacting iron levels.
Gastrointestinal (GI) Bleeding: This is a major cause in men and post-menopausal women. GI bleeding can result from several conditions, including stomach ulcers, gastritis, inflammatory bowel diseases like Crohn's or ulcerative colitis, and colon polyps or cancer. The bleeding may be slow and go unnoticed, draining the body's iron stores over time.
Frequent Blood Donation: Regular blood donors are at a higher risk of iron deficiency due to the iron loss with each donation.
Urinary Tract Bleeding: Conditions leading to blood loss in the urine, such as intravascular hemolysis, can also cause iron depletion.
Injury and Surgery: Significant blood loss during major surgery or physical trauma can rapidly deplete iron.

Dietary Factors Inhibiting Iron Absorption

Even with an iron-rich diet, certain foods and drinks can hinder the body's ability to absorb iron, particularly the non-heme iron found in plant-based sources.

Phytates: Found in whole grains, cereals, and legumes, phytates bind to non-heme iron and reduce its absorption. Soaking, sprouting, or fermenting these foods can help mitigate this effect.
Tannins and Polyphenols: These compounds in tea, coffee, cocoa, and red wine can significantly inhibit non-heme iron absorption. It is best to consume these beverages a couple of hours away from iron-rich meals.
Calcium: High doses of calcium from supplements or dairy products can interfere with the absorption of both heme and non-heme iron. It is advisable to take iron and calcium supplements at different times of the day.

Medical Conditions and Medications

Several health issues and treatments can impair iron absorption or increase the body's iron needs.

GI Disorders: Conditions like celiac disease, Crohn's disease, and H. pylori infection damage the intestinal lining, impeding the absorption of nutrients, including iron.
Bariatric Surgery: Procedures that bypass parts of the small intestine, like gastric bypass, reduce the surface area available for absorption, often leading to iron deficiency.
Kidney Disease: Chronic kidney disease can cause iron deficiency because the kidneys produce less erythropoietin, a hormone needed to make red blood cells.
Chronic Inflammation: Conditions that cause long-lasting inflammation, such as rheumatoid arthritis, can interfere with how the body regulates and uses iron.
Medications: Proton pump inhibitors (PPIs) and other acid-reducing medications can decrease stomach acid, which is necessary to convert non-heme iron into an absorbable form. Regular use of NSAIDs like aspirin can also cause GI bleeding, leading to iron loss.

Physiological Demands

Certain life stages and activities demand a higher iron intake, and if not met, can lead to depletion.

Pregnancy and Breastfeeding: The iron requirement increases significantly during pregnancy to support the increased blood volume and the developing fetus. Postpartum, breastfeeding mothers also have higher iron needs.
Growth Spurts: Children and adolescents undergoing rapid growth require more iron.
Intense Exercise: Endurance athletes lose iron through sweating and the breakdown of red blood cells (hemolysis) during vigorous training, increasing their risk of deficiency.

Comparison of Factors Affecting Iron Levels


Factor Type	Example	Mechanism of Depletion	Impact on Absorption
Chronic Blood Loss	Heavy Menstruation	Directly removes iron-containing blood from the body.	No direct impact on absorption, but increases iron need.
Chronic Blood Loss	GI Bleeding (Ulcers)	Slow, internal bleeding leads to gradual iron loss.	No direct impact on absorption, but increases iron need.
Dietary Inhibitor	Tannins (Tea/Coffee)	Bind to non-heme iron, creating insoluble complexes that are not absorbed.	Strong inhibitory effect on non-heme iron.
Dietary Inhibitor	Phytates (Whole Grains)	Bind to non-heme iron, limiting its bioavailability.	Strong inhibitory effect on non-heme iron.
Medical Condition	Celiac Disease	Damages the small intestine, reducing the surface area for absorption.	Decreases overall absorption efficiency.
Medical Condition	Bariatric Surgery	Alters the digestive tract, limiting iron absorption.	Decreases overall absorption efficiency.
Medication	Proton Pump Inhibitors	Reduce stomach acid, which is vital for converting iron into an absorbable form.	Inhibits non-heme iron absorption.
Physiological Need	Pregnancy	Increases blood volume and provides for fetal development.	Increases the demand for iron beyond typical intake.

Conclusion

Iron depletion is a complex issue driven by a combination of blood loss, dietary choices, and underlying medical conditions. While inadequate dietary intake is a factor, especially for those on vegetarian or vegan diets, chronic blood loss from menstruation or the gastrointestinal tract is a leading cause in many populations. Lifestyle factors, such as frequent blood donation or intense exercise, also contribute. Understanding these varied causes is the first step toward effective management. A proper diagnosis from a healthcare provider is essential to determine the root cause and create a targeted treatment plan, which may involve dietary changes, supplements, or addressing an underlying condition. You can explore more about iron absorption on the National Institutes of Health website at ods.od.nih.gov/factsheets/Iron-HealthProfessional.

Frequently Asked Questions

Foods containing phytates (whole grains, legumes), tannins (tea, coffee, wine), and high levels of calcium (dairy products) can inhibit the body's absorption of iron, especially non-heme iron from plant sources.

Yes, coffee and tea contain compounds called tannins and polyphenols that can significantly reduce iron absorption. It is recommended to consume these beverages a few hours before or after an iron-rich meal.

Yes, some medications can affect iron levels. Proton pump inhibitors (PPIs) can reduce stomach acid needed for absorption, and long-term use of NSAIDs like aspirin can cause internal bleeding that leads to iron loss.

Vegetarians and vegans can be at a higher risk of iron depletion because they only consume non-heme iron, which is less efficiently absorbed than heme iron from animal products. However, a well-planned plant-based diet can still provide adequate iron.

Heavy menstrual bleeding causes a consistent loss of blood each month. Since iron is a component of red blood cells, this blood loss directly reduces the body's iron stores over time, particularly if dietary intake doesn't compensate.

Diseases like celiac disease, inflammatory bowel disease, and stomach ulcers can cause chronic blood loss or damage the small intestine, impairing its ability to absorb iron from food.

Yes, endurance athletes are at a higher risk of iron deficiency. Intense, regular exercise can increase iron loss through sweating and a breakdown of red blood cells, known as hemolysis.