Iron: Benefits, Dosage, Contraindications
Other name(s)
Fe
Family or group:
Minerals and Trace Elements
Indications
Rating methodology
EFSA approval.
Anemia ✪✪✪✪✪
Chronic anemia and iron deficiency often manifest insidiously. Clinical signs are polymorphic: asthenia, decreased libido, difficulty undertaking physical or intellectual efforts, neurosensory symptoms (dizziness, tinnitus), nail growth disorders (koilonychia), atrophic glossitis, dysphagia (difficulty passing food through the mouth, pharynx, or esophagus) with Plummer-Vinson syndrome (a disease combining dysphagia, iron-deficiency anemia, and oral lesions), eating behavior disorders (persistent ingestion of non-nutritive substances). The recommended nutritional intake of iron for adult men is 11 mg/day.
Posologie
Oral
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 taking oral iron at an average daily dose of 20 to 225 mg of elemental iron increases maternal hemoglobin levels by up to 1 g/dL compared to 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.
Posologie
Oral
20 - 225 mg
Child Development ✪✪✪✪✪
In the brain, iron plays a role in the development and functioning of tissue (especially for learning and memory) by participating, among other things, in the formation of myelin and the development of neuronal dendrites. European health authorities (EFSA, European Food Safety Authority, and the European Commission) have determined that products containing iron may claim to contribute to normal intellectual 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
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 to placebo in non-anemic women with borderline or low serum ferritin concentrations and unexplained fatigue symptoms. European health authorities (EFSA, European Food Safety Authority, and the European Commission) have determined that products containing iron may claim to help reduce fatigue.
Posologie
Oral
80 mg
12 - weeks
Cognitive Performance ✪✪✪✪✪
Oral iron intake appears to improve cognitive functions 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 teenage girls with iron deficiency. Furthermore, an iron supplement of 50 mg twice a week for 16 weeks seems to improve attention measures in teenage girls possibly suffering from anemia. Iron also seems to reverse developmental and learning deficits caused by iron deficiency in anemic infants.
Posologie
Oral
1300 mg
8 - weeks
ferrous sulfate
Randomised study of cognitive effects of iron supplementation in non-anaemic 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 haematologic measures in female high school students.
Restless Leg Syndrome ✪✪✪✪✪
Restless Legs Syndrome (RLS) is generally associated with iron deficiency anemia. Some clinical research shows that taking iron as ferrous sulfate at a dose of 325 mg twice daily for 12 weeks reduces symptoms similarly to taking pramipexole (a dopamine agonist indicated for early-stage Parkinson's disease and restless legs syndrome). Symptoms such as leg discomfort, the urge to move, and sleep disturbances improved significantly in about half of the patients taking either treatment. Additional clinical research shows that taking 325 mg of ferrous sulfate twice daily with 100 mg of vitamin C twice daily for 12 weeks reduces RLS symptoms compared to vitamin C alone in patients with RLS with 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 (either supplements or iron-fortified foods) for 1 to 2 months improves running performance compared to placebo. Iron is proposed to enhance physical performance in athletes. 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 slight reduction in fatigue. Moreover, despite the absence of anemia, hemoglobin levels increased with iron supplementation, which may explain the performance improvement by raising hemoglobin levels.
Posologie
Oral
30 - 200 mg
2 - months
Attention Deficit Disorders ✪✪✪✪✪
Clinical research shows that oral iron sulfate improves certain signs of Attention Deficit Hyperactivity Disorder (ADHD) in children with iron deficiency after 1 to 3 months of treatment. A dose of 5 mg/kg per day of oral iron sulfate has been used.
Posologie
Oral
5 mg/kg
3 - months
Properties
Essential
Within the cell, iron is essential to numerous processes such as DNA, RNA, and protein synthesis, electron transport, cellular respiration, cell proliferation and differentiation, and regulation of gene expression. While 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, iron plays a role in the development and functioning of tissue (especially for learning and memory) by participating, among other things, in the formation of myelin and the development of neuronal dendrites. Iron exists in two forms: heme iron (95% of iron) involved in forming hemoglobin, myoglobin, and certain enzymes (cytochromes), and non-heme iron (non-heme) including some enzymes (iron-sulfur cluster proteins), chaperone proteins, and iron transport and storage proteins (transferrin and ferritin). Finally, iron is a cofactor for numerous enzymes such as tyrosine hydroxylase (catecholamine synthesis), tryptophan hydroxylase (serotonin synthesis), ribonucleotide reductase (nucleotide synthesis), lipoxygenases (regulation of inflammation), etc. 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 intellectual functions, the synthesis of hemoglobin and red blood cells, oxygen transport in the body, normal functioning of the immune system, reducing fatigue, normal intellectual 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 plays a role in the development and functioning of tissue (especially for learning and memory) by participating, among other things, in the formation of myelin and the development of neuronal dendrites. Research suggests that children with attention-deficit/hyperactivity disorder (ADHD) are more likely to have iron deficiency. The level of iron deficiency appears to be positively correlated with the severity of ADHD symptoms. ADHD symptoms are linked to dopamine dysfunction where iron seems to play a role.
Usages associés
Safety dosage
Infant 7 to 11 months: 11 mg
Child 1 to 6 years: 7 mg
Child 7 to 11 years: 11 mg
Adult from 18 years: 11 mg
Breastfeeding woman from 18 years: 16 mg
Woman from 40 years: 11 mg
The nutrient intake level likely to meet the daily needs of a menopausal woman over 40 years old is 11 mg/day
Woman from 18 years: 16 mg
The nutrient intake level likely to meet the daily needs of a pre-menopausal woman over 18 years old is 16 mg/day.
Pregnant woman from 18 years: 16 mg
Child 12 to 17 years: 13 mg
Interactions
Médicaments
Levodopa: moderate interaction
There is evidence in healthy people that iron forms chelates with levodopa, reducing the amount of levodopa absorbed by about 50%. The clinical significance of this phenomenon has not been determined.
methyldopa: moderate interaction
Concomitant use of iron and methyldopa may decrease the absorption of the latter, leading to 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, whether natural or synthetic, enhances iron absorption when administered together. The effect of vitamin C on iron is more visible in anemic subjects than in normal subjects. Vitamin C can counteract the effect of substances that inhibit iron absorption such as dietary phytates, polyphenols, and tannins by reducing it 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 failure: use with caution
The absorption of supplemental iron is decreased in people requiring chronic hemodialysis.
Contraindications
Hemochromatosis: prohibited
Iron supplements should not be used in hemochromatosis, a genetic condition characterized by excessive iron absorption from the gut and toxic accumulation of this iron in various organs.
