Iron: benefits, dosage, contraindications
Other name(s)
Fe
Family or group:
Minerals and trace elements
Indications
Scoring methodology
EFSA approval.
Anemia ✪✪✪✪✪
Chronic anemia and iron deficiency often present in an insidious manner. nnThe clinical signs are varied: fatigue, decreased libido, difficulty sustaining physical or intellectual exertion, neurosensory manifestations (dizziness, tinnitus), disorders ofnnthe growth of the nails (koilonychia), atrophic glossitis, dysphagia (difficulty when food passes through the mouth, the pharynx or the esophagus) with Plummer-Vinson syndrome (a disease combining dysphagia, iron-deficiency anemia and oral lesions), eating behavior disorders (persistent ingestion of non-nutritive substances).;nnThe recommended dietary intake of iron for adult men is 11 mg/day.nn
Posologie
Orally
11 mg
Iron deficiency
Daily iron supplementation for improving anemia, iron status and health in menstruating women.
Effect of iron supplementation on hemoglobin response in children: systematic review of randomized controlled trials.
Iron supplementation in early childhood: health benefits and risks.
Benefits of iron supplementation for low birth weight infants: a systematic review.
Pregnancy ✪✪✪✪✪
Clinical research shows that oral iron taken at an average daily dose of 20 to 225 mg of elemental iron increases maternal hemoglobin levels by up to 1 g/dL compared with placebo and reduces the risk of maternal anemia by 62% to 73%. Some clinicians may recommend alternating days of iron administration to reduce gastrointestinal side effects.nn
Posologie
Oral
20 - 225 mg
Child development ✪✪✪✪✪
In the brain, iron is involved in the development and functioning of tissue (especially for learning and memory) by contributing, among other things, to the formation of myelin and to the development of neuronal dendrites.nnEuropean health authorities (EFSA, European Food Safety Authority and the European Commission) have determined that products containing iron may claim to contribute to the normal intellectual development of the child and to cell division, if and only if those products contain at least 2.1 mg of iron per 100 g, per 100 ml, or per package if the product contains only a single servingnn
Posologie
Oral
11 mg
Fatigue ✪✪✪✪✪
There is evidence that a specific ferrous sulfate supplement providing 80 mg of elemental iron per day taken for 4 to 12 weeks improved fatigue by up to 19% compared with placebo in non-anemic women with borderline or low serum ferritin concentrations and unexplained symptoms of fatigue. European health authorities (EFSA, European Food Safety Authority, and the European Commission) have concluded that products containing iron can claim to contribute to the reduction of fatigue.
Posologie
Oral
80 mg
12 - weeks
Cognitive performance ✪✪✪✪✪
Oral iron intake appears to improve cognitive function in iron-deficient children and adolescents. For example, taking 650 mg of iron twice daily for 8 weeks improved verbal learning and memory in non-anemic adolescent girls with iron deficiency. In addition, a 50 mg iron supplement taken twice weekly for 16 weeks appears to improve measures of attention in adolescent girls with possible anemia. Iron also appears to reverse developmental and learning deficits caused by iron deficiency in anemic infants.
Posologie
Oral
1300 mg
8 - weeks
ferrous sulfate
Randomized study of cognitive effects of iron supplementation in non-anemic iron-deficient adolescent girls.
The effect of iron deficiency and mental stimulation on Indonesian children's cognitive performance and development.
Effects of iron supplementation twice a week on attention score and hematologic measures in female high school students.
Restless legs syndrome ✪✪✪✪✪
Restless legs syndrome (RLS) is generally associated with iron-deficiency anemia. Some clinical research shows that taking ferrous sulfate at 325 mg twice daily for 12 weeks reduces symptoms comparably to taking pramipexole (it is a dopamine agonist indicated for the treatment of Parkinson's disease and early-stage restless legs syndrome). Symptoms such as leg discomfort, the urge to move, and sleep disturbances improved substantially in about half of the patients taking either of these treatments. Further clinical research shows that taking ferrous sulfate 325 mg twice daily with vitamin C at 100 mg twice daily for 12 weeks reduces RLS symptoms compared with vitamin C alone in patients with RLS who have low or normal serum ferritin levels.
Posologie
Oral
650 mg
12 - weeks
ferrous sulfate
Practice guideline summary: Treatment of restless legs syndrome in adults: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology.
Efficacy of oral iron in patients with restless legs syndrome and a low-normal ferritin: A randomized, double-blind, placebo-controlled study.
Sports performance ✪✪✪✪✪
Clinical research in healthy children shows that daily intake of 30 to 200 mg of iron (supplements or iron-fortified foods) for 1 to 2 months improves performance during a running exercise compared with placebo. nnIron is proposed to improve athletes' physical performance. A meta-analysis of 18 trials examined the effects of iron supplementation on fatigue and physical performance in people with iron deficiency but without associated anemia. Four studies found a small reduction in fatigue. In addition, despite the absence of anemia, hemoglobin levels were found to be increased by iron supplementation, which may explain the improvement in performance through increased hemoglobin levels. nn
Posologie
Oral
30 - 200 mg
2 months
Attention deficit disorders ✪✪✪✪✪
Clinical research shows that oral ferrous sulfate improves certain signs of attention deficit hyperactivity disorder (ADHD) in children with iron deficiency after 1 to 3 months of treatment.nnA dose of 5 mg/kg per day of oral ferrous sulfate was used.nn
Posologie
Oral
5 mg/kg
3 months
Properties
Essential
In the cell, iron is essential to many processes such as the synthesis of DNA, RNA and proteins, electron transport, cellular respiration, cell proliferation and differentiation, and the regulation of gene expression. Although iron is indispensable to all cells, its role in certain specialized tissues such as the brain, bone marrow, intestine, placenta and skeletal muscle is particularly important. In the brain in particular, iron is involved in tissue development and function (especially for learning and memory) by contributing, among other things, to myelin formation and the development of neuronal dendrites. Iron exists in two forms: heme iron (95% of iron), which is part of hemoglobin, myoglobin and certain enzymes (cytochromes), and non-heme iron (iron not associated with heme) including certain enzymes (including iron–sulfur center proteins), chaperone proteins, and iron transport and storage proteins (transferrin and ferritin). Finally, iron is a cofactor for many enzymes such as the tyrosine hydroxylase (synthesis of catecholamines), tryptophan hydroxylase (synthesis of serotonin), ribonucleotide reductase (synthesis of nucleotides), lipoxygenases (regulation of inflammation), etc. The European health authorities (EFSA, European Food Safety Authority, and the European Commission) have determined that products containing iron may claim to contribute to normal energy metabolism, normal cognitive function, the synthesis of hemoglobin and red blood cells, the transport of oxygen in the body, the normal functioning of the immune system, reduction of fatigue, normal cognitive development of children and cell division, if and only if these products contain at least 2.1 mg of iron per 100 g, 100 ml or per package if the product contains only one serving.
Usages associés
Neurological
In the brain, iron is involved in the development and function of tissue (especially for learning and memory) by contributing, among other things, to the formation of myelin and the development of neuronal dendrites.nnResearch suggests that children suffering from attention-deficit/hyperactivity disorder (ADHD) are more likely to have iron deficiency. The degree of iron deficiency appears to be positively correlated with the severity of ADHD symptoms. ADHD symptoms are linked to dopaminergic dysfunction in which iron appears to play a role.nn
Usages associés
Safe dosage
Infant aged 7 to 11 months: 11 mg
Child aged 1 to 6 years: 7 mg
Child aged 7 to 11 years: 11 mg
Adult aged 18 years and older: 11 mg
Breastfeeding woman aged 18 years and older: 16 mg
Woman aged 40 years and older: 11 mg
The nutrient intake level likely to meet the daily needs of a menopausal woman older than 40 years is 11 mg/day.
Woman aged 18 years and older: 16 mg
The nutrient intake level likely to meet the daily needs of a premenopausal woman older than 18 years is 16 mg/day.
Pregnant woman aged 18 years and older: 16 mg
Child aged 12 to 17 years: 13 mg
Interactions
Médicaments
Levodopa: moderate interaction
There is evidence, in healthy individuals, that iron forms chelates with levodopa, which reduces the amount of levodopa absorbed by about 50%. The clinical significance of this phenomenon has not been determined.
Methyldopa: moderate interaction
Concurrent use of iron and methyldopa may decrease the absorption of the latter, resulting in increased blood pressure.
Levothyroxine: moderate interaction
Iron can decrease the absorption and effectiveness of levothyroxine by forming insoluble complexes in the gastrointestinal tract.
Plantes ou autres actifs
Iron: moderate interaction
Vitamin C, natural or synthetic, improves iron absorption when administered together. The effect of vitamin C on iron is more noticeable in anemic subjects than in normal subjects. Vitamin C can neutralize the effect of substances that inhibit iron absorption, such as dietary phytates, polyphenols, and tannins, by reducing their effect and preventing the formation of less soluble ferric compounds.
Precautions
Type 2 diabetes: use with caution
Theoretically, a high dietary iron intake increases the risk of heart disease in women with type 2 diabetes.
Renal insufficiency: use with caution
The absorption of supplemental iron is reduced in people requiring chronic hemodialysis.
Contraindications
Hemochromatosis: contraindicated
Iron supplements should not be used in hemochromatosis, which is a genetic disease characterized by excessive intestinal iron absorption and toxic accumulation of this iron in various organs.
