TL;DR
- Iron stores represent reserves of iron that the body stores for future needs.
- The most important indicator of iron stores is ferritin.
- Hemoglobin can be normal even when iron reserves are depleted.
- Low ferritin can be the first sign of iron deficiency, even before anemia develops.
- Replenishing iron stores is important in order to prevent iron deficiency from developing again.
- In children, adequate iron reserves are especially important for growth, development, and everyday functioning of the body.
What Are Iron Stores?
When discussing the role of iron in the body, most people first think of hemoglobin and the blood count. However, the body does not use iron only for immediate needs. Part of the iron is stored and kept as a reserve for the body’s future needs.
These reserves are called iron stores.
The body uses iron every day for hemoglobin production, oxygen transport, energy production, and many other processes. When iron intake is insufficient or the body’s needs are increased, the body first begins to use its stored reserves.
This is why iron deficiency often develops gradually and can exist long before changes appear in the blood count.
According to a systematic review and meta-analysis published in the Journal of Global Health, which included more than 2.1 million children from 55 studies worldwide, iron deficiency and iron-deficiency anemia remain among the most common nutritional disorders in childhood.
(Source: Global prevalence of iron deficiency anaemia among children aged 5–12 years: a systematic review and meta-analysis)
What Is Ferritin?
Ferritin is a protein that stores iron in the body and is considered one of the most important indicators of iron reserves. It plays a key role in safely storing iron in cells, mostly in the liver, spleen, bone marrow, and muscles. When the body needs iron for the production of red blood cells, or for other processes, it “draws” iron from these reserves.
This is why doctors often measure ferritin levels when they want to assess whether the body has enough iron stores.
Low ferritin most commonly indicates reduced iron stores and may represent the first laboratory sign of iron deficiency.
According to clinical studies, ferritin levels can decrease even before pronounced iron-deficiency anemia develops, which is why ferritin is considered one of the most important indicators of early iron deficiency. However, it should be kept in mind that ferritin is also an acute-phase reactant in inflammation, and elevated values are present in all conditions in which an immune response has been activated. When interpreting results, it is important to consider whether the blood sample was taken during inflammation.
(Source: Iron Bisglycinate Chelate and Polymaltose Iron for the Treatment of Iron Deficiency Anemia: A Pilot Randomized Trial)
Can Hemoglobin Be Normal While Ferritin Is Low?
Yes. This is one of the most common situations that confuses parents and patients. Such a situation often confuses parents because the laboratory result may appear normal, while the doctor still recommends continuing iron supplementation. This is precisely why it is important to understand the difference between hemoglobin and iron stores.
When the body starts running out of iron, the iron stores are depleted first, meaning ferritin decreases. Only later, if the deficiency continues, hemoglobin decreases and iron-deficiency anemia develops. Reduced hemoglobin concentration and reduced red blood cell volume, or MCV, are already a late manifestation of iron deficiency and lead to the development of anemia. For example, a child may have normal hemoglobin but still have low ferritin. In such a situation, the body does not have enough iron reserves, so the doctor may recommend continuing supplementation in order to restore iron stores.
This means that a person can have:
- normal hemoglobin
- a normal blood count
- low ferritin
- depleted iron stores
This is why experts today increasingly emphasize the importance of timely recognition of low ferritin and correction of iron deficiency before pronounced anemia develops. Adequate iron reserves are especially important during periods of rapid growth, when the body has increased needs for this mineral.
Why Is It Important to Replenish Iron Stores?
One of the most common mistakes is stopping iron supplementation as soon as hemoglobin returns to normal values.
However, normal hemoglobin does not necessarily mean that iron stores have been restored.
If supplementation is stopped too early:
- ferritin may remain low
- iron reserves may remain depleted
- iron deficiency may develop again
- symptoms may return after a certain period of time
This is why the goal of iron supplementation is not only to normalize hemoglobin, but also to restore iron reserves, which are most commonly assessed by monitoring ferritin.
Why Are Iron Stores Especially Important in Children?
In children, the body does not use iron only for hemoglobin production. Iron is also necessary for growth and development processes.
It has an especially important role in:
- brain development
- maturation of the nervous system
- attention and concentration
- learning and memory
- energy production
Many parents notice that the child seems more tired, more irritable, or has difficulty concentrating, but they do not immediately connect these changes with iron status.
This is why experts emphasize that in children it is important not only to correct anemia, but also to restore iron stores so that the body has enough reserves during periods of intensive growth and development.
How Long Does It Take to Restore Iron Stores?
There is no single answer that applies to everyone.
The duration of iron supplementation depends on:
- age
- degree of deficiency
- initial ferritin level
- individual needs of the body
- doctor’s assessment
It is recommended that iron supplementation continue even after hemoglobin normalizes, precisely in order to allow iron stores to be restored. Most commonly, iron stores are replenished for at least 2 to 3 months after hemoglobin values normalize, which means that iron therapy usually lasts 3 to 6 months in total.
This is why regular check-ups and laboratory analyses are an important part of monitoring the success of therapy.
How Is the Success of Iron Supplementation Monitored?
In most children, venous blood sampling is avoided unless necessary, so in everyday pediatric practice a therapeutic iron test is carried out, based on monitoring hemoglobin concentration after iron is introduced into therapy, using a finger-prick blood sample. One month after therapy is introduced, hemoglobin concentration should increase by at least 10 g/L.
Checking the concentration of iron in the blood is not recommended because it is an unreliable indicator of iron reserves and represents circulating iron taken in through food or a product over the previous few days.
The best indicator of whether iron stores have been restored is ferritin. However, if the pediatrician and parents do not want to perform venous blood sampling in order to determine ferritin values, the recommendation is to empirically continue iron supplementation after hemoglobin levels normalize for a minimum of 2 to 3 months.
What Do Clinical Studies Show?
Clinical studies show that successful correction of iron deficiency does not only mean increasing hemoglobin, but also restoring iron reserves.
A study by Name and colleagues showed that iron supplementation can contribute to a significant increase in ferritin levels and restoration of iron stores in people with iron deficiency.
(Source: Iron Bisglycinate Chelate and Polymaltose Iron for the Treatment of Iron Deficiency Anemia: A Pilot Randomized Trial)
In addition, numerous studies confirm that ferritin is an important indicator of the success of long-term correction of iron deficiency.
A Modern Approach to Iron Supplementation
In children, good tolerability of iron preparations is especially important because supplementation often lasts for a longer period of time.
Modern forms of iron, such as iron (II) bisglycinate chelate, are characterized by good absorption and gastrointestinal tolerability.
A randomized study published in the journal Clinical Therapeutics showed that iron bisglycinate chelate may have better gastrointestinal tolerability compared with ferrous sulfate, with a lower incidence of gastrointestinal side effects.
(Source: Tolerability of iron: a comparison of bis-glycino iron II and ferrous sulfate)
In the study by Pineda and Ashmead, conducted in infants and young children with iron deficiency, iron (II) bisglycinate chelate showed high bioavailability and good tolerability.
(Source: Effectiveness of treatment of iron-deficiency anemia in infants and young children with ferrous bis-glycinate chelate)
The Ferroly® for you preparation contains iron in the form of iron (II) bisglycinate chelate and enables precise dosing adapted to the child’s age.
Frequently Asked Questions
What Are Iron Stores?
Iron stores represent reserves of iron that the body stores for future needs.
What Does Ferritin Show?
Ferritin is the most important indicator of iron reserves in the body.
Can Hemoglobin Be Normal While Ferritin Is Low?
Yes. Low ferritin often represents the first sign of iron deficiency and can occur before anemia develops.
Why Should Iron Be Continued When Hemoglobin Is Normal?
Because time is often needed to restore iron stores and increase ferritin levels.
How Long Does It Take to Restore Iron Stores?
The duration depends on the degree of deficiency, age, and the doctor’s assessment.
How Are Iron Stores Checked?
Most commonly by determining ferritin levels through laboratory analyses.
Does Low Ferritin Mean That a Child Has Anemia?
Not necessarily. Low ferritin may be a sign of depleted iron stores and can occur before iron-deficiency anemia develops.
Iron deficiency is a common problem and, in most cases, an easily manageable one when recognized on time. Timely diagnosis, an adequate diet, and proper iron supplementation can help not only normalize hemoglobin, but also restore iron stores, which are important for normal functioning of the body.
Text prepared by: Estela Gaković Ranisavljević, Specialist in Pharmacy
The text was prepared based on available professional literature and published clinical studies.
Literature
- Sukwuttichai P, Tidwong N, Chaipichit N, et al. Global prevalence of iron deficiency anaemia among children aged 5–12 years: a systematic review and meta-analysis. Journal of Global Health. 2026;16:04027.
- Pineda O, Ashmead HD. Effectiveness of treatment of iron-deficiency anemia in infants and young children with ferrous bis-glycinate chelate. Nutrition. 2001;17(5):381–384.
- Name JJ, Vasconcelos AR, Valzachi Rocha Maluf MC. Iron bisglycinate chelate and polymaltose iron for the treatment of iron deficiency anemia: A pilot randomized trial. Current Pediatric Reviews. 2018;14(4):261–268.
- Coplin M, Schuette S, Leichtmann G, Lashner B. Tolerability of iron: a comparison of bis-glycino iron II and ferrous sulfate. Clin Ther. 1991;13(5):606–612.
- Beard JL. Why Iron Deficiency Is Important in Infant Development. The Journal of Nutrition. 2008.
- Lozoff B. Iron Deficiency and Child Development. Food and Nutrition Bulletin. 2007.
- Lozoff B, Jimenez E, Hagen J, Mollen E, Wolf AW. Poorer Behavioral and Developmental Outcome More Than 10 Years After Treatment for Iron Deficiency in Infancy. Pediatrics / JAMA Pediatrics.
- World Health Organization (WHO). Anaemia in children aged 6-59 months.
- World Health Organization (WHO). WHO guidance helps detect iron deficiency and protect brain development.
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