Iron is essential for many vital processes. When people go to their doctor to get their iron tested, almost always, the results are not scrutinized, even though we know that you can be healthier and live longer when your results lie within optimal ranges.
Iron deficiency can lead to anemia and several health problems. Read this post to learn about the negative health effects of iron deficiency.
This post is part 2 of a 4 Part Series
Part 2: 47 Negative Health Effects of Iron Deficiency
Negative Health Effects of Iron Deficiency
Iron Deficiency is Linked to Poor Cognitive Development in Children
In terms of brain development and brain health in infants and children, iron is critical for:
- brain and neurological development .
- normal functioning of the brain .
- neurotransmitter production (dopamine and noradrenaline)
- myelination of nerve cells
- immune function in the brain
- hippocampal structure and function [2, 3, 4].
1) Attention Deficit Hyperactivity Disorder
Lower iron and ferritin levels are associated with increased hyperactivity in children with ADHD [5, 6]. Blood ferritin levels were low (<30 ng/mL) in 84% of the children with ADHD as compared to 18% of healthy children [7, 8, 9]. Children with ADHD also have lower blood levels of iron and ferritin .
Low brain iron stores may contribute to ADHD symptoms because low iron levels in the brain can alter the activity of dopamine, a neurotransmitter involved in movement, cognitive functions, and attention .
Low iron level in the brain is a promising marker of ADHD [6, 17] as children with ADHD have lower iron in the thalamus . However, other studies did not detect low ferritin in children with ADHD, suggesting that blood iron measures may not provide reliable markers for ADHD [17, 18, 19, 20].
Iron deficiency and anemia are prevalent among autistic children [21, 22, 12]. Iron deficiency may contribute to learning and behavioral impairments observed in children with autism spectrum disorder (ASD)
Iron deficiency may contribute to learning and behavioral impairments observed in children with autism spectrum disorder (ASD) . The risk for ASD increases with lower maternal iron intake
The risk for ASD increases with lower maternal iron intake . However, not all autistic children have low iron
However, not all autistic children have low iron .
3) Causes Mental Retardation and Delayed Development
- mild or moderate mental retardation [34, 35, 12]
- slower brain development
- poorer school performance later in childhood 
- lower scores on language, movement measures, and environmental sound perception [36, 26, 27].
- lower IQ
- poorer attention and memory
- slower language and motor development
Children with iron deficiency anemia are more than twice as likely to score below average on standardized tests than children with normal iron status .
Iron Deficiency and Cognitive/Mental Health in Adults
4) Associated with Depression/Anxiety
Severe chronic iron deficiency in infancy is associated with a higher prevalence of anxiety, depression, and attention problems later in life .
Iron deficiency can cause abnormal dopaminergic neurotransmission and depress dopaminergic activity.
Weaning rats fed an iron-deficient diet showed decreased physical activity and increased anxiety-like behavior with a reduction of brain dopamine receptors .
Both men and women with iron deficiency anemia have a markedly higher risk of developing an anxiety disorder .
5) Iron is Lower in Bipolar Disorder
There is a higher percentage of bipolar disorder among patients with iron deficiency anemia .
6) Low Iron is Associated with Tic Disorder
Females with iron deficiency anemia have a significantly increased risk of tic disorder .
Ferritin and blood iron levels were markedly lower in Tourette’s syndrome patients, indicating that lower iron availability may have a causal role in the progression of tics and other movement disorders .
Iron and Women’s Health
Women of reproductive age are at particular risk of iron deficiency .
Data from the National Health and Nutrition Examination Survey indicated that 12 – 16% of nonpregnant women aged 16 – 49 years have iron deficiency, and 2 – 4% have iron-deficiency anemia .
Heavy menstrual bleeding is the most common cause of iron deficiency anemia in the developed world .
- the use of an intrauterine device (IUD)
- a vegetarian diet
- accelerated growth during the teenage years
- intensive exercise
Women are at greater risk of experiencing fatigue and exhaustion and are 3 times more likely than men to feel fatigued .
7) Increases the Risks of Premenstrual Syndrome (PMS) and Worsens PMS symptoms
A low intake of iron is associated with a higher risk of premenstrual syndrome .
Taking dietary and iron supplements for 2 months reduced PMS symptoms considerably in all women having anemia .
Eating a diet that provided about 22 mg of iron every day for 10 years was linked to a 33% decrease in risks of developing premenstrual syndrome .
8) Linked to Pregnancy Complications
Anemia occurs in 35 – 75% of pregnancies in developing countries, and in 18% of pregnancies in developed countries .
Iron requirements are increased during pregnancy because the mother’s blood volume expands, and the developing fetus and placenta need iron to grow .
Apgar (Appearance, Pulse, Grimace, Activity, Respiration) scores, assessing newborn’s health, are significantly higher in infants born to iron-supplemented mothers .
Iron deficiency after delivery is associated with an increased risk of postpartum depression, increased prevalence of infections, fatigue, and exhaustion, and lower quality and quantity of breast milk produced [64, 65, 66, 67].
Iron is Important for Immune Function
- immune cell production
- cytokine production
- immune response
- the generation of reactive oxygen species required for killing pathogens
9) Compromises Immune Function
Iron deficiency is associated with some reduced function of lymphoid organs (tissues that produce lymphocytes) and immune cells, specifically:
- thymus degeneration, resulting in a decrease of T lymphocytes .
- reduced neutrophil activity against bacteria. Myeloperoxidase, an enzyme in neutrophils required for killing bacteria, needs iron to function . Neutrophil function is restored to normal with iron supplementation [74, 69, 75].
- reduced cytokine production, including IFN-gamma, TNF-alpha, IL-6, and IL-8
- reduced macrophage functions because iron accumulation within macrophages allow them to generate reactive oxygen species needed to combat infectious agents and cancer cells 
- Th2 dominance and lowered Th1 immune responses, which lowers the ability to fight off viral and bacterial infections . Also, functions and growth of Th1 cells are more sensitive to iron removal than Th2 cells in a cell-based study .
Antibody concentrations, production, responses to antigens, and complement levels (also called humoral immunity) are less affected by iron deficiency .
While iron deficiency hampers the recovery and morbidity of some infections, it seems to help with other infections .
10) Causes Skin Problems and Poor Wound Healing
Iron is essential for healthy skin, hair, and nails. Iron is required for collagen production.
Signs of iron deficiency include pale and itchy skin, skin infections (impetigo, candidiasis), fragile nails, and dry and brittle hair .
Severe deficiency results in decreased collagen production, and poor wound healing .
Iron Deficiency and Autoimmune Diseases
Chronic inflammation from infections and autoimmunity can cause iron deficiency, and anemia from chronic inflammation is the most common type of anemias . When the immune system is fighting off a pathogen, inflammatory cytokines increase iron stores and iron inside of immune cells, while lowering systemic iron in order to reduce the iron available to the pathogen.
Chronic inflammation also reduces iron absorption in the gut .
Also, iron can increase the production of several autoantigens initiating the process of autoimmunity .
Therefore, iron deficiency is associated with several autoimmune diseases, but iron deficiency may be the effect rather than the cause. However, not all autoimmune patients are anemic.
11) Linked to Rheumatoid Arthritis
The severity of the anemia is associated with the activity of the disease .
In patients with rheumatoid arthritis, iron accumulates in the joints. This iron in the joint may inflame the joints by producing dangerous oxygen molecules and attracting inflammatory cells .
However, iron therapy in rheumatoid arthritis patients without iron deficiency may worsen joint inflammation, pain, and dysfunction .
12) Associated with Systemic Lupus Erythematosus
Iron deficiency is common in patients with systemic lupus erythematosus (SLE) due to heavy menstrual bleeding and increased gut blood loss, caused by the use of drugs such as aspirin and oral anticoagulants [101, 102].
Anemia of chronic disease frequently accompanies SLE flareups and is a useful parameter of disease activity .
13) Linked to Inflammatory Bowel Disease
Iron deficiency occurs in about 60 – 80% of patients with IBD, and anemia occurs in approximately 30% of patients .
Iron deficiency anemia is due to chronic blood loss, poor dietary intake of iron, and reduced iron absorption due to tissue inflammation .
14) Linked to Celiac Disease
IDA was reported in up to 46% of patients with celiac disease, occurring more often in adults than children .
15) Linked to Autoimmune Gastritis
Autoimmune gastritis (inflammation of the stomach) is classically associated with pernicious anemia (anemia from low vitamin B12) in adults, but recent studies have reported its association with iron-deficiency anemia in both adults and children .
Autoimmune gastritis was present in 27% – 52% of patients with iron-deficiency anemia .
Infections that Lower Iron Levels
16) Helicobacter pylori Infection
H.pylori infection is associated with iron-deficiency anemia, particularly in children. The presence of iron deficiency is 40 % more prevalent in children infected with H.pylori than in healthy children .
GI bleeding and bacterial competition for iron may explain the deficiency of iron in afflicted patients .
17) Parasitic Infection
Subjects with intestinal parasitic infections commonly experience iron deficiency from chronic blood loss .
Iron Deficiency and Metabolic and Cardiovascular Health
Increased hepcidin production in obese people may account for this reduction of iron levels .
19) Impairs Thyroid Function
Deficiency of iron may have an adverse effect on thyroid function .
Iron deficiency decreases thyroid peroxidase function, an enzyme important in the synthesis of thyroid hormones, thereby leading to hypothyroidism (underactive thyroid) .
20) Decreases Body Temperature
Iron-deficient patients may have a decreased ability to maintain body temperature in response to cold .
21) Heart Failure
The European Society of Cardiology Guidelines for heart failure recommend an evaluation of iron status in all patients with suspected heart failure .
On the other hand, increased iron stores may be associated with an increased risk of heart diseases, especially in men and menopausal women.
22) Worsens Blood Pressure Medications (ACE inhibitor)-induced Cough
A dry cough is a common side effect of blood pressure-lowering drugs that are angiotensin-converting enzyme (ACE) inhibitors, such as Capoten and Vasotec.
An ACE inhibitor-induced cough may be associated with excessive production of dangerous nitrogen molecules in bronchial cells caused by iron deficiency.
Iron deficiency impairs the protective mechanisms of airway lining .
Iron supplementation successfully decreases ACE inhibitor-induced cough .
23) Increases Risk of Stroke
Previously healthy children with stroke were 10 times more likely to have iron deficiency anemia than healthy children without stroke .
Thrombocytosis due to iron deficiency anemia is a rare but recognized cause of stroke .
Other Negative Effects of Iron Deficiency
Iron deficiency anemia is significantly associated with pica, a condition where patients develop unusual cravings for nonfood items like ice and dirt .
25) May Cause Restless Leg Syndrome
Restless legs syndrome (RLS), also called Willis-Ekbom disease, is characterized by an urge to move the legs and transient relief with movement.
The symptoms occur at rest, are worst at night, and often interfere with sleep .
Iron deficiency may be involved in disease development, possibly by affecting the production of the neurotransmitter dopamine .
The treatment of RLS includes iron therapy and the use of drugs like dopamine agonists .
Iron supplementation improves RLS symptoms.
26) Decreases Physical Performance
Iron deficiency can affect physical performance by:
- lowering tissue cytochrome c and muscle myoglobin to about 50% of the normal values [167, 168, 169]
- decreasing oxygen uptake and use by muscles [170, 171, 172, 173]
- reducing oxygen supply to the heart and muscles, resulting in fatigue and decreased exercise performance [170, 174]
Work performance in anemic individuals may be improved with iron supplementation.
Iron deficiency anemia is found in 2% of male and in 2.5% of female athletes because heavy athletic training increases iron need.
Athletes also have a significant decrease in red blood cell number, hemoglobin and ferritin levels .
27) Iron is Lower in Fibromyalgia
Low blood ferritin is associated with a 6.5 fold increased risks for fibromyalgia. This could be because iron is required for the production of serotonin, dopamine, and norepinephrine, which were found to be low in the cerebrospinal fluid of fibromyalgia patients .
28) Causes Fatigue
Its deficiency increased fatigue and decreases the quality of life in women .
29) Lung Diseases
Iron deficiency is more common in patients with chronic obstructive pulmonary disease (COPD) than in those without the lung condition .
- decreased blood oxygen levels
- worsening of COPD symptoms
- decreased exercise intolerance
- poor clinical outcome for COPD
- high blood pressure in the lungs without known causes (idiopathic pulmonary arterial hypertension)
Treating iron deficiency and anemia in COPD patients may reduce shortness of breath .
It is associated with lower exercise capacity, disease severity and poor clinical outcome.
Treatment of iron deficiency may improve high blood pressure in the lungs .
32% of pediatric and 60% of adult cystic fibrosis patients are deficient in iron, and the iron deficiency is associated with the severity of the disease .
30) May Play a Role in Hair Loss
Iron may play a role in hair loss in premenopausal women .
Iron supplementation can help reduce hair loss .
In a study, 18 women with hair loss experienced 100% hair regrowth in after taking oral iron therapy. The hair loss recurred when iron therapy was discontinued .
Hair follicle cells are sensitive to decreased iron, thus resulting in decreased hair growth in the presence of iron deficiency .
However, other studies showed no association between iron deficiency and female hair loss . Therefore, currently, there is not sufficient evidence to recommend screening for iron deficiency in patients with hair loss or to recommend giving iron supplementation to patients with hair loss and iron deficiency .
31) Decreases Appetite
Iron deficiency is associated with decreased appetite and growth in children .
Iron deficiency increases leptin, which reduces appetite and food intake .
32) Iron is Very Low in Chronic Kidney Disease (CKD)
33) May Worsen Toxic Effects of Lead Poisoning
This post is part of a 4-part series about iron.
Part 2: 47 Negative Health Effects of Iron Deficiency
Low Iron Levels?
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