PICA & IRON DEFICIENCY: What Every Parent Should Know
PICA & IRON DEFICIENCY · What Every Parent Should Know
A closer look at pica in children, its possible connection to iron deficiency, and the practical steps parents can take.
Tali Engor, B.Sc. Pharm, B.Sc Pharmaceutical Chemistry
Licensed Pharmacist & Pharmaceutical Chemist Founder & Scientific Director, C.A.T. Center
B.Sc Pharmacy
B.Sc. Pharmaceutical
Chemist
20+ Years of Experience in Pharmaceutical Chemistry
Scientifically reviewed under the direction of Tali Engor
This article reflects Tali Engor's work interpreting complex laboratory findings and
nutrition and biochemical factors in children on the autism spectrum
- Is Pica Really Associated With Iron Deficiency?
- Association Does Not Prove Causation
- Can a Child Have Iron Deficiency Without Anemia?
- What About Zinc Deficiency?
- Pica in Autistic Children: A More Complex Picture
- Is Pica Behavioral or Biological?
- Does Treating Iron Deficiency Make Pica Stop?
- What If Pica Continues After Iron Treatment?
- Iron Absorption, Inflammation and Hepcidin
- Could the Gut Environment Influence the Response to Iron?
- What Should Be Considered When a Child Has Pica?
- The Most Important Distinction
Frequently Asked Questions
What Is Pica?
This guide walks through what pica is, what the science does and doesn’t say about its link to iron deficiency, and the practical, safe steps that make sense for your family.
Pica refers to the persistent consumption of non-food, non-nutritive substances in a manner that is inappropriate for a child’s developmental stage. Depending on the child, this may involve substances such as:
- Paper
- Cardboard
- Dirt or soil
- Clay
- Chalk
- Paint
- Hair
- Fabric
- Soap
Pagophagia – the persistent or compulsive consumption of ice – is also commonly discussed as a specific form of pica and has been particularly associated with iron deficiency. However, pica should not necessarily be viewed as one single biological phenomenon.
Eating soil, repeatedly consuming paper, and persistently consuming ice are all behaviors that may fall under the broad concept of pica, but that does not necessarily mean that the same mechanism is responsible for each one.
This distinction matters when trying to understand the relationship between pica and nutritional deficiencies.
In very young children, putting objects into the mouth can also be part of normal developmental exploration. Pica generally refers to persistent consumption that is developmentally inappropriate rather than occasional mouthing of objects
Is Pica Really Associated With Iron Deficiency?
Clinical Insight
Clinical Perspective by Tali Engor, B.Sc. Pharm, B.Sc. Pharmaceutical Chemistry
There is substantial evidence of an association between pica and abnormalities related to iron status.
A major meta-analysis examining 43 studies and more than 16,000 participants found that individuals with pica had approximately 2.4 times the odds of anemia compared with those without pica.
Pica was also associated with lower average hemoglobin and hematocrit concentrations, and the association was observed in analyses involving children.
However, an important distinction is often lost when these findings are discussed.
Much of the strongest population-level evidence concerns anemia and hemoglobin rather than iron deficiency defined specifically by biochemical markers of iron stores.
These conditions overlap, but they are not identical.
A child may develop depleted iron stores before hemoglobin falls sufficiently for anemia to be diagnosed.
Therefore, evidence that pica is associated with anemia should not automatically be translated into a precise estimate of how frequently children with pica have iron deficiency without anemia.
The evidence supports an association. It does not make pica a diagnostic test for iron deficiency.
Association Does Not Prove Causation
The association between pica and iron abnormalities can potentially be explained in several ways.
Iron deficiency may contribute to pica
One possibility is that changes in iron status influence biological pathways involved in unusual cravings or eating behavior.
This hypothesis is biologically plausible, but the exact mechanism has not been established.
Although iron has important functions throughout the nervous system, those functions alone do not explain why a particular child might begin eating paper, soil, or another non-food substance.
At present, science does not have a complete answer.
Some forms of pica may contribute to nutritional problems
The relationship could also operate in the opposite direction.
Depending on the substance consumed, some forms of pica may affect nutrient intake or interfere with nutrient absorption.
This possibility may be particularly relevant to certain forms of geophagy — the consumption of soil or clay — but should not automatically be generalized to every form of pica.
Another factor may contribute to both
Pica and iron deficiency may sometimes occur together because both arise from another underlying factor rather than because one directly causes the other.
For example, a child with a highly restricted diet could be at increased risk of inadequate iron intake while independently displaying sensory-driven oral behaviors.
These possibilities are not mutually exclusive, and different mechanisms may apply to different children.
Blood iron circulates in the bloodstream, while ferritin serves as the body’s primary iron storage protein. Ferritin levels generally reflect iron stores, although they may also be influenced by inflammation and should always be interpreted within the child’s overall clinical context.
In This Article
1. What Is Pica? 2. Is Pica Really Associated With Iron Deficiency? 3. Association Does Not Prove Causation 4. Can a Child Have Iron Deficiency Without Anemia? 5. What About Zinc Deficiency? 6. Pica in Autistic Children: A More Complex Picture 7. Is Pica Behavioral or Biological? 8. Does Treating Iron Deficiency Make Pica Stop? 9. What If Pica Continues After Iron Treatment? 10. Iron Absorption, Inflammation and Hepcidin 11. Could the Gut Environment Influence the Response to Iron? 12. What Should Be Considered When a Child Has Pica? 13. The Most Important Distinction Frequently Asked Questions ```
Laboratory-Guided Autism Support
At C.A.T. Center, we use advanced laboratory testing to identify biological and nutritional factors that may be affecting your child's focus, behavior and well-being.
Can a Child Have Iron Deficiency Without Anemia?
Yes.
Iron deficiency develops along a continuum. Iron stores can decline before hemoglobin falls sufficiently for the child to meet the criteria for anemia. This means that a normal hemoglobin result does not always rule out depleted iron stores.
Ferritin is commonly used to help assess stored iron, while other measurements can provide additional information about iron availability and red blood cell status. However, laboratory interpretation also requires context.
Ferritin is an acute-phase reactant, and inflammation can increase ferritin concentrations independently of iron stores. As a result, a normal or elevated ferritin concentration does not always exclude iron deficiency when significant inflammation is present.
This is one reason why interpreting iron status can require more than looking at a single laboratory value.
What About Zinc Deficiency?
Iron is not the only micronutrient that has been associated with pica. Research has also found an association between pica and lower zinc concentrations. In the same meta-analysis that found higher odds of anemia among individuals with pica, pica was also associated with lower plasma zinc concentrations in the studies that measured zinc status. However, as with iron, an association does not establish that zinc deficiency causes pica.
The available evidence is also more limited and less consistent than the evidence linking pica with anemia and abnormalities related to iron status. This means that when a child has persistent pica, particularly alongside a restricted diet or other signs of possible nutritional deficiency, focusing exclusively on iron may provide an incomplete picture. Depending on the child’s individual circumstances, the broader nutritional context — including zinc status — may also deserve consideration.
Pica should therefore be viewed as a possible signal that nutritional assessment may be warranted, rather than as evidence of one specific nutrient deficiency.
Pica in Autistic Children: A More Complex Picture
Pica appears to be substantially more common among autistic children than among children in the general population.
In a large study of preschool-aged children, pica was reported in approximately 3.5% of the general-population control group compared with 23.2% of children with autism.
The prevalence was even higher among autistic children who also had intellectual disability.
These findings establish an important association between autism and pica.
They do not, however, tell us why the association exists.
Possible contributors may include:
- Sensory-seeking behavior
- Developmental factors
- Restricted eating patterns
- Learned behavioral reinforcement
- Nutritional abnormalities
The important point is that these possibilities can coexist.
Is Pica Behavioral or Biological?
When an autistic child repeatedly eats paper or another non-food substance, the behavior may quickly be described as sensory or behavioral.
In another setting, the same behavior may be attributed entirely to a nutritional deficiency.
Both interpretations can become overly simplistic.
A child may simultaneously have:
- A sensory drive toward a particular texture
- A highly selective diet
- An iron deficiency
- A learned behavioral component that reinforces the behavior
Finding iron deficiency does not prove that the deficiency caused the pica.
But identifying a sensory explanation does not prove that the child’s iron status is normal.
A behavioral explanation and a biological finding do not necessarily compete with one another.
In an autistic child, identifying a behavioral or sensory explanation for pica should not automatically end the medical investigation — just as finding iron deficiency does not prove that the deficiency caused the behavior.
Does Treating Iron Deficiency Make Pica Stop?
The answer is more complicated than is often suggested.
Numerous clinical reports describe pica improving or disappearing after iron deficiency was corrected.
These observations have contributed to the widespread belief that iron deficiency can directly cause pica.
They are important observations, but they do not provide definitive proof of causation.
Case reports and uncontrolled studies cannot reliably determine whether the improvement occurred specifically because iron was restored or whether other factors contributed.
Controlled intervention evidence is limited.
In at least some controlled studies of specific forms of pica, including geophagy, iron supplementation did not significantly reduce the behavior.
This means that observations of improvement after iron treatment should not be generalized to every form of pica or interpreted as proof of a universal causal mechanism.
Correction of iron deficiency may be associated with improvement in pica in some individuals, but response to iron treatment does not establish a universal mechanism for pica.
Iron deficiency should be appropriately addressed when it is identified.
But the presence of iron deficiency should not automatically end the investigation into why a particular child has pica.
What If Pica Continues After Iron Treatment?
A lack of improvement can provide useful information, but it should not lead immediately to one conclusion.
Several possibilities should be considered.
The iron deficiency may not have been the primary driver
The pica may have sensory, behavioral, developmental, or other contributors that remain present after iron status improves.
Iron deficiency may still be present
The child may not yet have achieved adequate correction of the deficiency.
The underlying cause of the deficiency may still be active
Low dietary intake, restricted eating, impaired absorption, ongoing blood loss, or other medical factors may continue to affect iron status.
Inflammation may be affecting iron availability
Iron status is regulated not only by how much iron enters the diet. It is also influenced by a hormone called hepcidin.
Importantly, this is one possible explanation for persistent abnormalities in iron status.
It is not an established explanation for persistent pica itself.
Another nutritional deficiency may also be present
Lower zinc concentrations have also been reported in individuals with pica, although the evidence is less consistent than the evidence relating pica to anemia and abnormalities in iron status.
Persistent pica after iron treatment should not automatically be interpreted as evidence of zinc deficiency, but focusing on iron alone may sometimes provide an incomplete nutritional picture.
Iron Absorption, Inflammation and Hepcidin
Hepcidin is one of the body’s central regulators of iron metabolism.
When hepcidin levels rise, the activity of ferroportin — a protein involved in moving iron into the circulation — is reduced.
This can decrease intestinal iron absorption and restrict the release of iron from body stores into the circulation.
Inflammation can increase hepcidin signaling.
This creates an important distinction between iron being present in the body and iron being sufficiently available for physiological use.
Research in inflammatory conditions, including pediatric inflammatory bowel disease, supports a relationship between inflammation, hepcidin regulation, and reduced iron availability or absorption.
This does not mean that every child with iron deficiency has an inflammatory problem.
It means that when iron status does not respond as expected, the underlying biological context may matter.
Simply increasing iron intake does not explain why the deficiency developed or why it persists.
Could the Gut Environment Influence the Response to Iron?
Please never start your child on an iron supplement on a hunch. Test first — then treat only if the results and your doctor say so.
The safety point that matters most
Iron overdose is one of the leading causes of poisoning in young children. Iron tablets can look like sweets, and a relatively small number swallowed by a small child can cause serious harm. If there are any iron supplements in your home — including a parent’s or an older sibling’s — keep them locked well out of reach.
This is an emerging and considerably less established area of research.
The gastrointestinal tract contains a complex ecosystem of bacteria, fungi, metabolites, immune signals, and host cells.
Research, including studies in pediatric populations, has shown that oral iron can influence the intestinal microbial environment in some contexts, partly because not all orally administered iron is absorbed.
However, these effects are not uniform across all populations, formulations, doses, or clinical circumstances.
Microorganisms themselves also have complex relationships with iron.
One organism of particular interest is Candida albicans.
C. albicans requires iron for important biological processes and possesses sophisticated systems that allow it to acquire and regulate iron under different environmental conditions.
Experimental research suggests that the iron environment can influence aspects of Candida biology and gastrointestinal colonization.
However:
There is currently insufficient clinical evidence to conclude that intestinal Candida overgrowth directly depletes a child’s systemic iron stores or prevents iron supplementation from correcting an iron deficiency.
The research therefore raises a broader question rather than providing a clinical conclusion:
Could the gastrointestinal environment influence why some individuals respond differently to oral iron?
At present, that question remains open.
Clinical Insight
Clinical Perspective by Tali Engor, B.Sc. Pharm, B.Sc. Pharmaceutical Chemistry
When a child has both confirmed iron deficiency and pica, identifying and appropriately addressing the deficiency is important — but the deficiency may not explain the entire clinical picture.
If iron status does not improve as expected despite appropriately managed supplementation, the next question should not automatically be how to provide more iron.
It should also be why the expected response has not occurred.
Inadequate intake, impaired absorption, ongoing losses, and inflammation can all influence iron status. In selected cases, the gastrointestinal environment may also deserve consideration as part of the broader clinical picture.
At present, the possibility that significant alterations in the intestinal microbial or fungal environment influence the response to oral iron remains a hypothesis requiring further research.
There is insufficient clinical evidence to conclude that intestinal Candida overgrowth directly causes systemic iron deficiency or prevents medically indicated iron treatment from working.
When an expected biological response does not occur, investigating why may provide more information than simply assuming that more of the same intervention is needed.
What Should Be Considered When a Child Has Pica?
There is no single laboratory test that explains pica.
The appropriate evaluation depends on the individual child, including:
- What substance is being consumed
- How often and for how long
- Whether the child actually swallows the substance
- Dietary variety and nutritional intake
- Symptoms or evidence of nutritional deficiency
- Gastrointestinal symptoms
- Developmental and behavioral factors
- Possible exposure to toxic substances
When iron deficiency is a concern, evaluation may include a complete blood count and appropriate measures of iron status, interpreted within the child’s broader clinical context.
Depending on what the child consumes, additional investigation may also be necessary.
Some forms of pica can create risks related to:
- Lead exposure
- Gastrointestinal obstruction
- Infection
- Dental injury
The purpose of evaluation should not be to find one explanation as quickly as possible.
It should be to identify the factors that are actually relevant to that particular child.
The Most Important Distinction
- Iron helps the brain make dopamine, a chemical central to focus — so it plausibly matters for attention.
- For children on the autism spectrum, iron status may be one useful part of a broader laboratory-guided evaluation, especially when attention, sleep, restricted eating, or gastrointestinal issues overlap.
- Research suggests a link between low iron and attention difficulties in some children, but the evidence is mixed and iron is not a proven cause.
- A child can have low iron stores before anaemia shows up, so ferritin is usually the key test — read by a doctor, in context.
- Food is the sensible foundation, and pairing plant iron with vitamin C noticeably improves absorption.
- Never supplement on a guess: too much iron is genuinely dangerous. Test first, then treat only with medical guidance.
Frequently asked questions
It may contribute in some children, but the relationship is more complex than it is often presented.
Research consistently shows an association between pica and anemia or abnormalities in iron status, but association does not prove that iron deficiency causes every case of pica.
Some children improve after iron deficiency is corrected, while others continue to display pica because nutritional, sensory, developmental, or behavioral factors may also be involved.
No.
Persistent consumption of paper, dirt, cardboard, chalk, or other non-food substances may be a sign of pica, but the behavior itself cannot diagnose iron deficiency.
Instead, it should be viewed as a possible clinical signal that deserves appropriate evaluation.
Yes.
Iron stores can become depleted before hemoglobin falls enough for anemia to develop.
This means that a child may have low iron stores while a routine blood count still appears normal.
Several explanations are possible.
The iron deficiency may not have been the primary contributor, it may not yet have been fully corrected, or its underlying cause may still be present.
Restricted eating, impaired absorption, inflammation, gastrointestinal factors, sensory processing differences, and other nutritional deficiencies may also continue to contribute.
Yes.
Research indicates that pica is considerably more common among autistic children than among children in the general population.
However, autism alone does not explain why pica develops.
Not without appropriate medical evaluation.
Iron supplementation should be considered only when a deficiency has been identified and should be managed under the guidance of a qualified healthcare professional.
Giving iron solely because a child displays pica is not an appropriate substitute for testing and individualized assessment.
Yes. Two children may repeatedly eat the same substance yet have entirely different underlying contributors.
This is why pica should be evaluated as a symptom rather than as a diagnosis in itself.
The gastrointestinal environment interacts with iron in complex ways, and microorganisms such as Candida albicans depend on iron for important biological processes.
However, current clinical evidence is insufficient to conclude that intestinal Candida overgrowth directly causes systemic iron deficiency or prevents medically indicated iron supplementation from working.
Clinical Insight
Clinical Perspective by Tali Engor, B.Sc. Pharm, B.Sc. Pharmaceutical Chemistry
One of the greatest challenges in evaluating pica is avoiding the assumption that every child has the same underlying cause.
In clinical practice, identifying iron deficiency is an important finding, but it is rarely the entire explanation.
Understanding why the deficiency developed, whether it explains the child’s symptoms, and whether the expected biological response to treatment has occurred is often just as important as identifying the deficiency itself.
Rather than viewing laboratory results in isolation, they should be interpreted alongside the child’s:
- Nutritional status
- Gastrointestinal health
- Dietary habits
- Developmental history
- Sensory profile
- Symptoms
- Overall clinical presentation
An abnormal laboratory finding may be highly relevant, but it should always be considered within the broader clinical context.
This perspective reflects the clinical approach developed by Tali Engor, B.Sc.Pharm., B.Sc. in Pharmaceutical Chemistry, founder of the C.A.T. Center, where laboratory findings are integrated with individualized nutritional assessment to better understand the biological factors that may contribute to each child’s unique clinical presentation.
Selected References
The scientific information presented in this article is based on internationally recognized clinical guidelines, peer-reviewed medical literature, and current evidence regarding iron metabolism, pediatric nutrition, neurodevelopment, and iron deficiency.
The references below represent a selection of the primary clinical guidelines and peer-reviewed publications that informed this article.
Diagnostic Criteria & Clinical Definitions
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders: DSM-5-TR. 5th ed., text revision. American Psychiatric Association Publishing; 2022.
Young SL. Pica in Pregnancy: New Ideas About an Old Condition. Annual Review of Nutrition. 2010;30:403–422.
Pica & Iron Deficiency
Miao D, Young SL, Golden CD. A Meta-analysis of Pica and Micronutrient Status. American Journal of Human Biology. 2015;27(1):84–93. doi:10.1002/ajhb.22598.
Nemeth E, Ganz T. The Role of Hepcidin in Iron Metabolism. Acta Haematologica. 2009;122(2–3):78–86. doi:10.1159/000243791.
Government & Professional Guidelines
National Institutes of Health (NIH), Office of Dietary Supplements. Iron – Fact Sheet for Health Professionals.
World Health Organization (WHO). Use of Ferritin Concentrations to Assess Iron Status in Individuals and Populations: Guideline. Geneva: World Health Organization; 2020.
World Health Organization (WHO). Guideline: Daily Iron Supplementation in Infants and Children. Geneva: World Health Organization; 2016.
Baker RD, Greer FR; Committee on Nutrition, American Academy of Pediatrics. Diagnosis and Prevention of Iron Deficiency and Iron-Deficiency Anemia in Infants and Young Children (0–3 Years of Age). Pediatrics. 2010;126(5):1040–1050.
Royal Children’s Hospital Melbourne. Clinical Practice Guidelines: Iron Deficiency.
Pica in Autism & Neurodevelopmental Disorders
Fields VL, Soke GN, Reynolds A, et al. Pica, Autism, and Other Disabilities. Pediatrics. 2021;147(2):e20200462. doi:10.1542/peds.2020-0462.
Iron Metabolism & Biological Mechanisms
Camaschella C. Iron-Deficiency Anemia. New England Journal of Medicine. 2015;372(19):1832–1843. doi:10.1056/NEJMra1401038.
A note for readers
This article is intended for general educational purposes only and does not provide medical advice, diagnosis, or treatment recommendations. Persistent pica should be discussed with an appropriately qualified healthcare professional, particularly when a child swallows potentially harmful substances or when nutritional deficiency is suspected. Iron supplementation should not be started, stopped, or changed solely because a child has pica. Iron deficiency and an inadequate response to treatment require appropriate professional evaluation based on the individual child’s clinical circumstances and laboratory findings.