Simply put, without enough iron, the human body cannot work properly. Iron is required throughout the body. It is essential for the production of red blood cells, and ensuring that the heart and skeletal muscles can function effectively3. Iron also plays a vital role in fighting off infections and illness4, maintaining energy levels4 and normal brain function.
Iron deficiency means that there is not enough iron available in the body to enable it to function properly6.
When the body's available iron stores are low (iron deficiency) it can impact almost all aspects of life, such as your metabolism, mental and physical health, work productivity and even sexual function4,7. The World Health Organization states that iron deficiency can lead to a reduction of 30% in physical work output8.
Want to know the full effects that iron has on the body? Take a look at our Role of Iron infographic.
Iron deficiency is the main cause of anaemia9. It occurs when the level of iron stored in the body is so low, or non-existent, the body can no longer make enough haemoglobin needed to develop healthy red blood cells10. Haemoglobin is the protein found inside red blood cells that carries oxygen to tissues and organs throughout the body, which is essential for them to function properly11.
To better understand the meaning of different iron levels, take a look at this infographic.
There is a clinical difference between iron deficiency and iron deficiency anaemia6. Having low iron availability (iron deficiency), doesn't necessarily mean you will develop iron deficiency anaemia. To determine whether someone is iron deficiency or has iron deficiency anaemia, a blood test is performed which will look at a number of things:
Iron deficiency is very common, present in one-third of people around the world2. It is most prevalent in premenopausal and pregnant women and children under the age of five15. In Europe for example, iron deficiency affects up to 33% of pre-menopausal women, up to 77% of pregnant women, and up to 48% of children15.
Iron deficiency also often affects those with chronic inflammatory diseases. It is estimated to affect 37-61% of patients with chronic heart failure (CHF), 24-85% of patients with chronic kidney disease (CKD) and 13-90% of patients with Inflammatory bowel disease (IBD)6.
Despite the serious consequences and high prevalence of iron deficiency16, it is an under-recognised condition17,18. As a result, many people are unaware that their health and well-being are being compromised. Even among those who are aware of iron deficiency, some still cannot recognise its symptoms19.
It is because of this lack of awareness that we are focused on education about the symptoms and impact of iron deficiency. If you recognise any of the symptoms, we recommend that you speak to a healthcare professional. Take a look at the Symptom Checker to find out more about the numerous and varied symptoms.
The consequences of iron deficiency differ from person to person, but it can be linked to an overall decline in general health and well-being, as well as an increase in fatigue20. Even in the absence of anaemia, iron deficiency can be debilitating, and exacerbate any underlying chronic disease, leading to increased morbidity and mortality6. In children, iron deficiency can significantly impair cognitive and motor development21.
People of all ages can become iron deficient, but there are certain times in life and certain lifestyle choices, that can make it more likely to happen:
The blood lost during menstruation (periods) means that pre-menopausal women need up to twice as much iron in their diet as men to avoid becoming iron deficient22. Women who have particularly heavy periods are more prone to iron deficiency and should discuss this with a healthcare professional. Blood loss also contributes to the development of iron deficiency in patients with inflammatory bowel disease (IBD), chronic heart failure (CHF) and chronic kidney disease (CKD)6.
The inflammation associated with certain long-term conditions, such as IBD, CHF or CKD can reduce the amount of iron absorbed by the gut and therefore lead to iron deficiency6.
Some medications used in the treatment of CHF or CKD can lead to blood loss, reduce absorption or increase demand for iron6.
Iron is needed for the body to grow, so during times of growth, the need for iron increases. This includes pregnancy, infancy (in children less than five years of age) and adolescence23.
Iron can be found in both animal products and plant foods, but iron from animal products is better absorbed by the body24. Foods rich in iron include red meats (liver, steak etc.), eggs, pulses, beans, nuts and seeds8. Restrictive diets, either by choice (vegetarian or vegan diets) or due to chronic illness, can increase the risk of iron deficiency25,26,27.
The symptoms of iron deficiency are varied and can be similar to those of other conditions, making a diagnosis challenging6,7. In a consultation with a healthcare professional it is important to list all of the symptoms you are experiencing; take a look at the Symptom Checker to see if you recognise any.
Once your medical history has been taken, if your healthcare professional suspects iron deficiency, they will arrange for a blood test to check the red blood cells and iron levels in your body7. This is a simple procedure that requires a small sample of blood, usually from the arm. A laboratory will test the blood for several different things which can confirm iron deficiency, and if so, how much iron is lacking. The amount of iron required by the body varies between people, so your doctor will discuss the results with you18.
It is important that iron deficiency and iron deficiency anaemia are diagnosed and treated, as they can have a significant impact not only on quality of life and overall functioning of the body, but also on long-term chronic conditions2,6. If you think you may have iron deficiency, speak to your doctor. Use our patient discussion guide and Symptom Checker to help you prepare for a consultation with your healthcare professional.
There are a number of ways that iron deficiency can be treated and this depends upon the level of deficiency and the medical history of the patient. Options include increasing iron in your diet, oral iron supplements or intravenous iron (given via a drip)7.
1 Hassan, Tamer Hasan et al. “Impact of Iron Deficiency Anemia on the Function of the Immune System in Children.” Medicine 95.47 (2016): e5395. PMC.
2 Peyrin-Biroulet L, et al. Guidelines on the diagnosis and treatment of iron deficiency across indications: a systematic review. Am J Clin Nutr.2015;102(6):1585-94.
3 Camaschella C. 2015. Iron‐deficiency anemia. N. Engl. J. Med. 372:1832–1843
4 Beard JL. Iron biology in immune function, muscle metabolism and neuronal functioning. J Nutr. 2001:568-580.
5 Pinero DJ, Connor JR. Iron in the Brain: An Important Contributor in Normal and Diseased States. Neurosci. 2000;6(6):435-453.
6 Cappellini MD et al. Iron deficiency across chronic inflammatory conditions: International expert opinion on definition, diagnosis, and management. Am J Hematol. 2017 Oct;92(10):1068-1078.
7 Auerbach M, Adamson JW. How we diagnose and treat iron deficiency anemia. Am J Hematol. 2016;91(1):31-38.
8 World Health Organisation. Iron deficiency anaemia. Assessment, prevention and control: A guide for programme managers. 2001. Available at URL: http://www.who.int/nutrition/publications/en/ida_assessment_prevention_control.pdf Last accessed: June 2018.
9 World Health Organisation. Nutritional anaemias: tools for effective prevention and control. 2017. Available at URL: http://www.who.int/nutrition/publications/micronutrients/anaemias-tools-prevention-control/en/. Last accessed: June 2018.
10 Fernando B, et al. A guide to diagnosis of iron deficiency and iron deficiency anemia in digestive diseases. World J Gastroenterol. 2009 Oct 7; 15(37): 4638-4643.
11 PubMed Health. Erythrocytes (red blood cells). Available at URL: https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0022014/. Last accessed: June 2018.
12 World Health Organization. Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. Vitamin and Mineral Nutrition Information System. Available at URL: http://www.who.int/vmnis/indicators/haemoglobin.pdf. Last accessed: June 2018.
13 National Heart Lung and Blood Institute. How is Iron Deficiency Anemia Diagnosed. Available at URL: https://www.nhlbi.nih.gov/health/health-topics/topics/ida/diagnosis. Last accessed: June 2018.
14 Elsayed M, et al. Transferrin Saturation: A Body Iron Biomarker. Adv Clin Chem. 2016;75:71-97.
15 Hercberg S, et al. Iron deficiency in Europe. Public Health Nutr. 2007;4(2b).
16 World Health Organisation. Worldwide prevalence of anaemia 1993-2005. 2008. Available at URL: http://apps.who.int/iris/bitstream/handle/10665/43894/9789241596657_eng.pdf;jsessionid=9C613E2F4D481EDEB9DE07986AFCE0C7?sequence=1. Last accessed: June 2018.
17 Thachil J. Iron deficiency: still under-diagnosed? Br J Hosp Med. 2015;76(9):528-532.
18 Miller JL. Anemia: a common and curable disease. Cold Spring Harb Perspect Med. 2013 Jul; 3(7).
19 Caramelo L, Mezzacasa A and Kassebaum NJ. Iron Deficiency. Understanding perceptions of sufferers and the general public. EHA 21st Annual Congress, 9-12 June 2016, Copenhagen, Denmark
20 Patterson A, et al. Iron deficiency, general health and fatigue: Results from the Australian Longitudinal Study on Women’s Health. Qual Life Res.2000;9:491-497.
21 World Health Organisation. Nutritional anaemias: tools for effective prevention and control. 2017. Available at URL: http://www.who.int/nutrition/publications/micronutrients/anaemias-tools-prevention-control/en/. Last accessed: June 2018.
22 Zimmermann M, Hurrell R. Nutritional iron deficiency. Lancet. 2007;370:511-520.
23 Abbaspour N, et al. Review on iron and its importance for human health. J Res Med Sci. 2014;19(2):164-174.
24 Hurrell R, Egli I. Iron bioavailability and dietary reference values. Am J Clin Nutr. 2010;91:1461-1467.
25 Hunt JR. Bioavailability of iron, zinc, and other trace minerals from vegetarian diets. Am J Clin Nutr. 2003;78(3).
26 Waldmann A, et al. Dietary iron intake and iron status of German female vegans: results of the German vegan study. Ann Nutr Metab. 2004;48(2):103-8.
27 McDonagh T, Macdougall IC. Iron therapy for the treatment of iron deficiency in chronic heart failure: intravenous or oral? Eur J Heart Fail. 2015;17(3):248-62.
28 Favrat, B, et al. (2014). Evaluation of a single dose of ferric carboxymaltose in fatigued, iron-deficient women--PREFER a randomized, placebo-controlled study. PLoS One 9(4): e94217. eCollection 2014.
29 Nijrolder I, et al. Diagnoses during follow-up of patients presenting with fatigue in primary care. CMAJ. 2009;181(10):683-7.
30 Schieffer KM, et al. Association of Iron Deficiency Anemia With Hearing Loss in US Adults. JAMA Otolaryngol Neck Surg. 2017;(800).
31 Trost LB, et al. The diagnosis and treatment of iron deficiency and its potential relationship to hair loss. J Am Acad Dermatol. 2006;54(5):824-44.
32 Cashman MW, Sloan SB. Nutrition and nail disease. Clin Dermatol. 2010;28(4):420-5.
33 Whitfield A, et al. Iron Deficiency Anemia Diagnosed in Female Teenagers. J Family Med Community Health. 2015. 2(7): 1058.
34 Scully C. ABC of oral health: Mouth ulcers and other causes of orofacial soreness and pain. Bmj. 2000;321(7254):162-165
35 Barton JC, et al. Pica associated with iron deficiency or depletion: clinical and laboratory correlates in 262 non-pregnant adult outpatients. BMC Blood Disord. 2010;10:9. doi:10.1186/1471-2326-10-9.
36 Silber MH, et al. Willis-Ekbom Disease Foundation Revised Consensus Statement on the Management of Restless Legs Syndrome. Mayo Clin Proc.2013;88(9):977-986.
37 Brigham D, Beard J. Iron and thermoregulation: a review. Crit RevFood Sci Nutr. 1996;36(1040-8398):747-763.
38 Jankowska E, et al. Iron deficiency: an ominous sign in patients with systolic chronic heart failure. Eur Heart J. 2010;31(15):1872-80.
39 Fallah R, et al. Evaluation Efficacy of Ferrous Sulfate Therapy on Headaches of 5-15 Years Old Iron Deficient Children with Migraine. Iran J Pediatr Hematol Oncol. 2016;6(1):32-7.