Why do iron deficient people chew ice?

January 7, 2026 •

5 min read

In a study of individuals with iron deficiency anemia, researchers found that 56% reported experiencing pagophagia—the compulsive craving for and chewing of ice. This peculiar habit, in which iron deficient people chew ice, is a well-documented symptom of the condition, though the exact physiological mechanism is not yet fully understood.

Quick Summary

The craving to chew ice, or pagophagia, is a pica disorder commonly associated with iron deficiency anemia. Proposed explanations include a temporary increase in mental alertness due to enhanced cerebral blood flow or relief from oral inflammation caused by the deficiency.

Key Points

Craving ice is a medical symptom: Persistent ice-chewing, known as pagophagia, is a common sign of pica, an eating disorder linked to nutritional deficiencies.
Iron deficiency is the primary cause: A strong craving for ice is often indicative of iron deficiency anemia and typically resolves once the deficiency is treated.
It offers temporary mental relief: Chewing ice may temporarily increase blood flow to the brain, boosting alertness and combating the fatigue and mental fog from low iron levels.
It can also soothe oral symptoms: For some, the cold sensation may relieve pain from glossitis (swollen tongue) or dry mouth, which are other symptoms of anemia.
Pagophagia is harmful to your teeth: Compulsively chewing ice can lead to significant dental damage, including cracked teeth, enamel erosion, and harm to existing fillings.
The cure is treating the deficiency: Chewing ice does not fix the iron deficiency; the only effective treatment is addressing the root cause through medical intervention, like iron supplements.
Medical consultation is essential: Anyone with a persistent ice-chewing habit should consult a doctor to get tested for iron deficiency and rule out other potential causes.

The Connection Between Iron Deficiency and Pagophagia

Pagophagia, or the compulsive consumption of ice, is a type of pica often seen in people with iron deficiency anemia. While the consumption of ice does not provide any iron, the craving is a significant behavioral symptom that frequently resolves once iron levels are restored. The precise reason for this link remains an area of ongoing research, with several compelling hypotheses.

The Brain Perfusion Theory

One of the leading theories suggests that chewing ice triggers a physiological response that temporarily benefits the brain function of iron-deficient individuals.

Enhancing Cerebral Blood Flow: Researchers hypothesize that the cold stimulus in the mouth activates the trigeminal nerve, causing vasoconstriction in the periphery and diverting more blood flow to the brain. This temporary increase in cerebral blood flow may provide a much-needed oxygen boost to combat the fatigue and sluggishness caused by anemia.
Improving Alertness: Studies have shown that chewing ice can improve cognitive performance, specifically response times on neuropsychological tests, but only in anemic subjects. This suggests that the ice-chewing is a self-soothing mechanism that provides a temporary burst of alertness, helping to counteract the mental fog associated with low iron levels.

The Oral Relief Hypothesis

Another possibility is that chewing ice provides a soothing sensation for oral symptoms often associated with iron deficiency.

Inflammation: Some people with anemia develop glossitis (a sore, swollen tongue) or stomatitis (inflammation of the mouth). The cold from the ice can numb the inflamed tissue, offering temporary relief from discomfort.
Dry Mouth: The condition can also cause xerostomia, or dry mouth. Chewing ice can help produce saliva and provide temporary moisture.

Why Chewing Ice is Not a Solution

While the craving and the temporary relief it provides are compelling, it is crucial to understand that chewing ice does not treat iron deficiency. Instead, it can cause significant harm to your dental health over time. The habit is a symptom, not a cure, and the underlying deficiency requires proper medical treatment.

Comparison of Iron Deficiency Theories


Feature	Brain Perfusion Theory	Oral Relief Hypothesis
Primary Mechanism	Chewing ice triggers a neurological response that increases blood flow and oxygenation to the brain.	The cold sensation of ice provides soothing relief for oral inflammation and dryness.
Effect on Cognitive Function	Documented improvement in cognitive performance and alertness specifically in iron-deficient subjects.	Potential to alleviate discomfort, which may improve focus, but lacks direct cognitive enhancement.
Scientific Evidence	Supported by studies showing improved neuropsychological test performance in anemic individuals who chew ice.	Based on observational reports and the known symptom of glossitis in anemic patients.
Nature of Benefit	Acts as a temporary stimulant to combat fatigue and mental sluggishness caused by oxygen deprivation.	Provides physical comfort and reduces pain or irritation in the mouth and tongue.
Resolution with Treatment	Often resolves completely once iron levels are restored with supplements or therapy.	Resolves as the underlying oral symptoms caused by the deficiency heal with treatment.

The Dangers of Untreated Pagophagia

Ignoring the persistent craving for ice and failing to address the underlying iron deficiency can lead to a cascade of health issues. Most notably, the constant habit of chewing hard ice can cause significant dental problems, including damaged tooth enamel, cracked teeth, and harm to existing dental work. Furthermore, if the craving is so severe that it replaces food intake, it can exacerbate malnutrition. Untreated iron deficiency anemia itself can lead to serious health complications, such as heart problems, issues during pregnancy, and developmental delays in children.

Conclusion: Seeking Medical Advice is Crucial

The phenomenon of iron deficient people who chew ice is a complex interplay of physiological and neurological factors. While the immediate act might offer a temporary sense of relief or mental clarity, it is a clear indicator of an underlying nutritional deficiency. Recognizing this habit as a potential symptom of anemia is the first step toward proper diagnosis and effective treatment. Addressing the root cause with iron supplementation and dietary adjustments is the only way to permanently resolve the craving and prevent further health complications. If you or someone you know has a persistent and unexplained craving for ice, it is essential to consult a healthcare provider for a blood test and a comprehensive evaluation. Treating the deficiency, not the symptom, is the key to regaining health. More information about the link between pica and nutritional deficiencies can be found on resources like the American Society of Hematology, a leading authority on blood disorders.

Practical Steps to Manage Pagophagia

Consult a Doctor: The most important step is to get a proper medical diagnosis and a blood test to check for iron deficiency.
Address the Root Cause: Follow your doctor's recommendations, which will likely include iron supplements and dietary changes to correct the deficiency.
Protect Your Teeth: While working on the underlying deficiency, try to let ice melt in your mouth rather than chewing it to prevent dental damage.
Find Alternative Satisfactions: If the crunch is the main draw, replace ice with healthier, crunchy alternatives like baby carrots, apple slices, or frozen grapes.
Hydrate Differently: Drink cold water or other cool, healthy beverages instead of chewing ice.
Manage Other Symptoms: Treat other symptoms of iron deficiency, such as oral inflammation, with your doctor's guidance.
Monitor Progress: The craving for ice should decrease as your iron levels improve with treatment. Report any persistence to your doctor.

The Neurobiological Angle: A Deeper Look

Research on the brain's response to pagophagia suggests that the cold from the ice may activate the sympathetic nervous system. This, combined with the activation of the dive reflex—a physiological response triggered by cold stimulation—could cause blood vessels to constrict and redirect blood flow to vital organs, including the brain. For a person with iron-deficiency anemia, whose brain may be experiencing a reduced oxygen supply due to fewer red blood cells, this increased blood flow could provide a temporary cognitive boost, which the body begins to crave. This theory aligns with the observation that improved alertness and performance are only seen in iron-deficient individuals who chew ice, not in healthy controls.

Frequently Asked Questions

The medical term for a compulsive craving to chew and consume ice is pagophagia. It is classified as a form of pica, an eating disorder characterized by consuming non-food items.

While an intense and persistent craving for ice is strongly correlated with iron deficiency, it is not the only potential cause. Other factors, including other nutritional deficiencies, psychological issues like stress or OCD, and dry mouth, can also cause pagophagia.

Researchers theorize that chewing ice can increase blood flow to the brain by activating the nervous system or the 'diving reflex'. This provides a temporary boost of oxygen and alertness to combat the fatigue caused by low iron levels.

No, chewing ice does not treat or cure iron deficiency. It is merely a symptom of the underlying condition. The only way to resolve the deficiency is through proper medical treatment, typically with iron supplements or dietary changes.

Yes, regularly chewing ice can be harmful to your teeth. It can chip or crack your teeth, damage enamel, irritate gums, and dislodge dental work like fillings or braces.

The craving for ice often resolves remarkably quickly once a person begins iron replacement therapy. Some studies have shown a decrease in cravings within days to weeks of starting treatment.

If you have a persistent ice-chewing habit, you should see a healthcare provider for a blood test to check your iron levels. While awaiting diagnosis, you can try safer alternatives like chewing baby carrots or frozen fruit, or letting ice melt instead of crunching.