Iron is a trace mineral that occurs in the body in two different chemical forms. Most Iron in the body is bound in the haemoglobin of red blood cells and in the myoglobin of muscle cells, where it is needed for the transport of oxygen (O2) and carbon dioxide (CO2) [1]. Ferritin, the so-called Iron storage substance, is an important parameter for the measurement of the iron storage in the organism, which is also much better suited than the Iron blood value to determine the status of the Iron supply, because the latter fluctuates very strongly in the course of the day.

National Nutrition Study

  • 14% of all men do not reach the recommended daily allowance of Iron.
  • 58% of all women do not reach the recommended daily allowance of Iron [22].

Function of Iron

An evaluation (analysis) of clinical studies with women of childbearing age shows that the intake of Iron increases performance values (performance parameters), such as the maximum oxygen intake capacity, but does not influence the values for duration of exhaustion and energy consumption [2]. A review of randomized controlled studies has shown that a supplementation (orally and intravenously) in iron defficient elite athletes results in an increase of aerobic performance parameters, better energetic efficiancy and increased knee extensor muscle strength. [3]

Main function of Ferritin is the storage of iron [4] [5] [6].

Iron is a component of haemoglobin, the oxygen-binding red blood pigment, a component of myoglobin, a structural protein in muscle cells, and occurs in some important enzymes [2] [3] [4].
It is involved in energy metabolism and the exchange of electrons in the body [2] [3] [4].
Iron has antioxidant properties [2] [3].

Deficiency Symptoms

Low Iron levels can lead to anaemia (iron deficiency anaemia), which corresponds to a decrease in red blood cells, the haemoglobin of the red blood cells or a lowering of the ability to bind oxygen (oxygen binding capacity). Symptoms of anemia are often difficult to detect. Possible symptoms are tiredness, weakness, shortness of breath, poor concentration and a drop in physical performance [7] [8] [9] [10] [11] [12] [13] [14].
Taking Iron supplements seems to improve cognitive function in children and adolescents with iron deficiency [15]. 650 mg of Iron twice a day for 8 weeks, for example, support language acquisition and memory in adolescent girls with Iron deficiency without anaemia. 1650 mg of iron twice a week for 16 weeks seems to improve attention parameters in female adolescents with possible anaemia. Iron is also believed to correct Iron deficiency-related developmental delays and learning disabilities in anaemic children [17].
An Iron deficiency leads to susceptibility to infection due to a weakening of the immune system [2] [3] [4].
An iron deficiency can lead to the degradation of the mucous membrane, which is regarded as the first barrier of the immune system. It can also lead to brittle hair and nails [2] [3].
More than 20% of patients with heart failure have Iron deficiency. Clinical research shows that the administration of 200 mg ferric(III)-carboxymaltose or 200 mg iron sucrose via the vein directly into the blood (intravenously), in patients with mild or moderate heart failure, is associated with an improvement in quality of life, resilience and a lower hospitalisation rate [19] [20].

Surplus of Iron

Excess Iron can lead to side effects such as nausea, inflammation of the mucous membranes and heartburn [2].
If there is a pronounced excess of iron over a longer period of time, liver damage (liver cirrhosis) may occur [2].

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[2] Pasricha SR, Low M, Thompson J, et al. Iron supplementation benefits physical performance in women of reproductive age: a systematic review and meta-analysis. J Nutr. 2014;144(6):906-14. (

[3] Clénin G, Cordes M, Huber A, Schumacher YO, Noack P, Scales J, Kriemler S. Iron deficiency in sports – definition, influence on performance and therapy. Swiss Med Wkly. 2015 Oct 29;145:w14196. (

[4] Koula-Jenik H, Miko M, Kraft M, Schulz RJ. Leitfaden der Ernährungsmedizin. München: Urban & Fischer, Elsevier; 2013. S.63-65

[5] Biesalski HK, Grimm P, Nowitzki-Grimm S. Taschenatlas der Ernährung. 7. Ausgabe. Stuttgart: Georg Thieme Verlag; 2017. S.118-131

[6] Raschka R, Ruf S. Sport und Ernährung: Wissenschaftlich basierte Empfehlungen, Tipps und Ernährungspläne für die Praxis. 4.Auflage. Stuttgart: Georg Thieme Verlag; 2015. S.128-130

[7] Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002. Available at:

[8] Iron for infants and toddlers. Pharmacist’s Letter / Prescriber’s Letter. 2010:26(11);261108.

[9] Baker RD, Greer FR; Committee on Nutrition. Diagnosis and prevention of iron deficiency and iron-deficiency anemia in infants and young children (0-3 years of age). Pediatrics. 2010;126(5):1040-50.(

[10] Killip S, Bennett JM, Chambers MD. Iron deficiency anemia. Am Fam Physician. 2007;75(5):671-8.(

[11] Fernandez-Gaxiola AC, De-Regil LM. Intermittent iron supplementation for reducing anaemia and its associated impairments in menstruating women. Cochrane Database Syst Rev 2011:CD009218. (

[12] Gera T, Sachdev H P, Nestel P, et al. Effect of iron supplementation on haemoglobin response in children: systematic review of randomised controlled trials. J Pediatr Gastroenterol Nutr. 2007;44(4):468-486. (

[13] Iannotti LL, Tielsch JM, Black MM, et al. Iron supplementation in early childhood: health benefits and risks. Am J Clin Nutr. 2006;84(6):1261-1276 (

[14] Long H, Yi JM, Hu PL, et al. Benefits of iron supplementation for low birth weight infants: a systematic review. BMC Pediatr. 2012;12:99. (

[15] Falkingham M., Abdelhamid A., Curtis P., et al.. The effects of oral iron supplementation on cognition in older children and adults: a systematic review and meta-analysis. Nutr J 2010;9:4. (

[16] Bruner AB, Joffe A, Duggan AK, et al. Randomized study of cognitive effects of iron supplementation in non- anaemic iron-deficient adolescent girls. Lancet. 1996;348(9003):992-6 (

[17] Soewondo S. The effect of iron deficiency and mental stimulation on Indonesian children’s cognitive performance and development. Kobe J Med Sci. 1995;41(1-2):1-17. (

[18] Iron replacement in heart failure. Pharmacist’s Letter / Prescriber’s Letter 2010;26(1):260177

[19] Anker SD, Comin Colet J, Filippatos G, et al. Ferric carboxymaltose in patients with heart failure and iron deficiency. N Engl J Med 2009;361(25):2436-48. (

[20] Avni T, Leibovici L, Gafter -Gvili A. Iron supplementation for the treatment of chronic heart failure and iron deficiency: systematic review and meta-analysis. Eur J Heart Fail. 2012 (4):423-9. (

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