Iron deficiency is considered one of the most common deficiencies in the world and is the most widespread cause of anaemia. If you discover that you have an iron deficiency, you can counteract this with a targeted change in diet or iron supplements.
Blood tastes like iron. The metallic taste is no coincidence: haemoglobin, the red blood pigment, consists mainly of iron. Iron plays an important role in blood formation and the transport of oxygen through the blood. If there is not enough iron in the body, it can lead iron deficiency anaemia.
Find out how to obtain enough iron from your diet – even if you are a vegetarian or vegan. You will also find out what causes iron deficiency, iron deficiency symptoms, and how to test the level of iron in your blood. Understand which iron supplements you should take and why you should not take iron unless you have a confirmed iron deficiency.
Iron and iron deficiency
Iron is part of the group of essential trace elements. Essential trace elements cannot be produced by the body itself. We have to absorb them through food.
The human body contains an average of four to five grams of iron. Iron occurs in different forms:
- Storage irons account for 25 per cent of the total amount of iron in our bodies, such as ferritin, which the body uses to store iron in the liver and bone marrow, among other things.
- Up to three per cent is contained in the transport protein transferrin, which is used to transport iron through the blood.
- Most of the iron in the body is bound to the red blood pigment haemoglobin.
What Is the function of iron in our bodies?
Every single cell in our body requires iron. Iron helps with oxygen transport and blood formation in organisms. Without iron, less of the red blood pigment haemoglobin is produced. Haemoglobin transports inhaled oxygen from the lungs around the entire body. The cells need the oxygen to carry out their metabolic processes. This is how iron supplies us with energy. The trace element also transports carbon dioxide back into the lungs and oxygen into the muscle cells.
Iron also strengthens skin, hair and nails, supports the immune system and promotes a healthy pregnancy.[2–4]
What happens if you are deficient in iron?
Iron deficiency is one of the most common deficiencies worldwide. A total of over 30 per cent of the world’s population is anaemic. This form of anaemia is usually accompanied by very distinct iron deficiency symptoms such as paleness, a feeling of weakness and hair loss. Senior citizens, pregnant women, vegans and vegetarians as well as people with gastrointestinal disorders are at a greater risk of iron deficiency.[5, 6]
What is the daily iron requirement?
How much iron you need will depend on your gender and age. According to the recommendations of the National Institutes of Health (NIH), men should consume ten milligrams of iron a day and women 15 milligrams. Women need more iron because of menstruation, during which they lose iron.
Pregnant women have the greatest daily iron requirement, needing 30 milligrams; breastfeeding women need 20 milligrams per day. Starting from menopause, women usually no longer have an increased need.7
|Recommended average intake||Iron in mg/day|
|Children (1 to 10 years)||8||10|
|Children (10 to 19 years)||12||15|
|Adults (19 to 50 years)||10||15|
|Adults (51 years or older)||10||10|
The U.S. National Institute of Health additionally advises vegetarians to multiply the recommended daily requirement by 1.8.8
Who is most at risk for iron deficiency anaemia?
Certain people are susceptible to iron deficiency for various reasons.[5, 9] These include the following risk groups:10–12
- Pregnant women and nursing mothers have an increased need – more blood is needed for the unborn child, then for breast milk.
- In some cases, senior citizens may suffer from a lack of appetite and chewing problems and, as a result, do not consume enough nutrients.
- Vegetarians and vegans consume less or no bivalent iron (the form of iron which the body absorbs particularly well) from animal foods.
- People with chronic gastrointestinal disorders often do not properly absorb iron.
- Professional athletes have a higher requirement and often eat a diet low in iron.
If you belong to one of the risk groups, it may be worth checking your levels regularly with an iron test. However, you should not use any iron supplements without first taking a laboratory test. Otherwise, you run the risk of excess iron and haemochromatosis.
Iron deficiency symptoms
If you do not have sufficient amounts of iron in your body, the trace element can no longer perform its most important function as well as it should – that is, supplying cells with oxygen. Cells that do not receive enough oxygen produce less energy, and their functions are limited.
If the brain, for example, does not receive enough oxygen, it can result in problems concentrating and fatigue. Additional symptoms of a deficiency are:1, 5
- hair loss, brittle nails, cracked corners of the mouth
- weakness, reduced performance, headaches
- anaemia (iron deficiency anaemia)
Can low iron levels cause hair loss?
One possible iron deficiency symptom is hair loss. Iron plays a decisive role in blood formation – and hair has a high blood requirement. If blood formation in the body does not run properly, the body first reduces blood flow to those parts of the body that are non-essential for survival – and this includes hair. If the hair does not receive enough blood as a result, it begins to fall out.2
The good news is that you may be able to treat hair loss by taking the right iron supplement. A study conducted in 2002, for example, showed that participants increased their iron levels (ferritin levels) from 33 to 89 milligrams per liter on average over the course of six months. At the same time, their rate of hair loss was reduced by 39 per cent.13
Iron deficiency causes
It is easy to tell whether you have an iron deficiency: your body consumes more iron than it receives; iron reserves are emptied.10 Possible causes are blood loss, a diet low in iron or a natural increased need due to pregnancy or competitive sports.
Iron deficiency is the most common cause of anaemia. It is responsible for around 50 per cent of cases of anaemia. With anaemia, the blood pigment haemoglobin is not produced in sufficient quantities. For this reason, the blood can only transport oxygen through the body to a limited extent.14
1. Blood loss
Blood loss can occur due to injuries, menstrual bleeding, blood donations, dialysis and internal bleeding. Internal bleeding may be caused by intestinal tumours and other gastrointestinal diseases.15
2. Reduced intake
One reason people have an iron deficiency can be that they simply do not consume enough iron through their diet. This can be the case, for example, for people who are on a diet, who eat a strict vegetarian or vegan diet, and who suffer from anorexia or intestinal parasites.
However, there are also illnesses that cause less iron to enter the blood from the intestine. Studies have shown that about two-thirds of people with chronic inflammatory bowel diseases, such as Crohn’s disease, develop iron deficiency anaemia. Coeliac disease can also lead to iron deficiency.16–18
3. Iron deficiency during pregnancy
Pregnant women need more iron to supply their uterus, placenta and embryo with blood and oxygen – especially towards the end of their pregnancy.19 The body of pregnant women must produce 30 to 40 per cent more blood. The daily iron requirement therefore doubles from 15 milligrams to 30 milligrams per day.20 Studies show that up to 30 per cent of expectant mothers in Europe develop iron deficiency anaemia due to the high iron requirement for iron.15
Scientists are still investigating how iron deficiency affects children. Some studies suggest that anaemia increases the risk of disease for mother and child and makes premature births and miscarriages more likely.20 In other studies, children whose mothers had been using iron supplements during pregnancy had a healthier birth.11
Iron deficiency in competitive athletes
Studies show that competitive athletes and fitness hobbyists require a greater amount of iron, especially during endurance sports. There are several theories as to why athletes need more iron – from a higher blood volume and greater sweat production to haemorrhages in the blood vessels of the feet. According to one theory, competitive sport promotes the release of the liver protein hepcidin, which blocks the absorption of iron in the intestines. In addition, endurance athletes often eat a diet rich in carbohydrates and low in meat – and thus low in iron.22
An iron deficiency is particularly restrictive for athletes because it can reduce physical performance. Iron ensures that oxygen and nutrients reach the muscles. If this function is limited, this can lead to a decrease in performance and muscle cramps.23
Testing for iron deficiency
You can detect an iron deficiency by taking a blood test. There are several values that a laboratory can determine from that test sample.
- Haemogoblin, for example, reveals how much iron is circulating in the blood at the time of the test.
- Doctors can also analyse ferritin (the storage form of iron) levels. In the laboratory, the amount of ferritin in one millilitre of blood is recorded, and this suggests your general iron levels. However, in people with chronic liver diseases or inflammatory reactions in the body, ferritin levels can be elevated without iron deficiency.
cerascreen Ferritin Test
The cerascreen Ferritin Test is a blood test to check for ferritin, the storage iron. You can perform this test at home using our test kit. Simply take a small amount of blood from your fingertip and send the sample to our laboratory, where your ferritin value is determined. Your results report will indicate whether your ferritin levels are within the normal range.
Treating iron deficiency: nutrition
Are your iron levels too low? A change in diet is often the solution to achieve normal iron levels. If this is not sufficient or if there is a severe deficiency or a disease associated with iron deficiency, iron supplements may be useful.
What foods are the highest in iron?
Iron is found in animal products – salted herring, pork and beef liver and chicken eggs are particularly rich in iron.
Among plant-based foods, legumes and whole-grain products in particular contain a lot of iron, but also chanterelles, spinach and beetroot. Iron is also found in some types of fruit, including coconut, mulberries, dried apricots and persimmons.
The following foods are richest in iron:25
|Foods||Iron content (milligrams per 100 grams)|
For those of you with a sweet tooth: 25 grams of dark chocolate will help your body release happiness hormones AND supply it with three milligrams of iron! You’re welcome!
Why is iron from animal products better than iron from plants?
The iron from animal foods has higher bioavailability. This means that our body can make better use of it. Animal foods, especially beef and pork, often contain haem iron, which the small intestine can absorb directly into the bloodstream. In turn, iron from plant-based foods must first be converted in the intestine. A large part of the iron is lost in the process – while the body absorbs up to 20 per cent of animal iron, it only absorbs five per cent of plant-based foods.
Why is vitamin C important for iron supply?
You can help your body utilise your iron intake more efficiently with vitamin C, a vitamin that promotes the absorption of iron in the intestine. For example, a glass of orange juice will help you make better use of the iron from a serving of whole-grain bread or oatmeal. Another recommendation is that you prepare a green smoothie with fresh fruit and iron-rich spinach or kale.
Want to optimise your iron intake with vitamin C? Then take note of these vitamin C boosters: broccoli, kale, Brussel sprouts, herbs (parsley, cress, fennel), bell peppers, spinach, rosehip, strawberry, orange, blackcurrant.
Red fruit juices, such as tomato, grape and plum juice are also a great source of iron. In pharmacies and health food shops, you can often purchase special juices that contain a lot of iron and are supposed to quickly fulfil your daily requirements. Make sure with such drinks that they contain vitamin C to support absorption and that no unnecessary sugar is added.25
What disrupts iron absorption?
While vitamin C optimises iron absorption, other types of food have the opposite effect. These so-called anti-nutrients include:1, 5, 26
- Dairy products: calcium salts in dairy products
- Lignin and phytates found in some whole-grain products
- Oxalic acid in spinach, beetroot, rhubarb and cocoa
- Phosphate in Coca Cola
- Polyphenol in coffee and tea
To reduce any negative impact such foods may have on iron absorption, you should not drink tea, coffee and milk directly with your meals. You can eat yogurt instead of milk with your cereal or herbal alternatives such as soy, rice or oat milk.
Whole-grain products and spinach, while containing anti-nutrients, still are a good source of iron. You can counteract the anti-nutrients in these food products by soaking whole grains and legumes in water and washing and cooking spinach thoroughly. This removes most of the anti-nutrients.1
Did you know that aspirin reduces iron absorption? This is due to the ingredient salicylate.
You can treat a mild iron deficiency with the right diet. Animal foods contain high-quality iron, which reaches the blood directly from the intestine. The intestine only absorbs small amounts of iron from plant-based foods. You can increase your iron intake by simultaneously consuming vitamin C. Inhibitors that impair absorption can often be removed from food by washing, cooking and soaking.
If you have an iron deficiency, you can quickly replenish your reserves with iron supplements. These supplements are usually found in the form of tablets or dietary powders, capsules and drops. Some are available over the counter, while others require a prescription or can only be purchased in pharmacies.
You should not take iron supplements based on only a suspicion that you are deficient in iron. Too much iron can also be harmful to your health. You should check your iron supply beforehand – for example, by visiting a doctor or by taking a medical self-test at home.
When should I consume iron?
The body is best able to absorb iron in the morning on an empty stomach. It is recommended to take iron supplements half an hour to an hour before breakfast. Drink a glass of orange or fruit juice or another beverage containing vitamin C. You should not drink tea or coffee for at least two hours before and after taking this product. Some iron supplements are medications – in this case, follow the instructions in the package.
Which iron supplements should I take – and for how long?
If you want to replenish your reserves, you should pay particular attention to the quality of the iron. Bivalent iron is the best choice, as it is this form that the body can absorb best. A common iron compound, which is also recommended by doctors, is Iron-(II)-sulphate.5
How long you should take iron supplements for depends on how severe your deficiency and how high your need is. A rule of thumb is that it takes at least 40 to 50 days to replenish depleted reserves.
Iron supplements can also have side effects, such as abdominal pain and constipation. If you experience adverse effects from taking an iron supplement, try to take it two hours after a meal or switch to trivalent iron.27
Iron supplements can cause stool to turn dark – this is no cause for concern.
For some people, supplements are not enough to replenish the iron reserves. In these cases, doctors can check your values and administer high-dose injections or iron infusions.28
Possible reasons why conventional iron supplements do not work could include:29
- The intestine has unusually severe difficulties with absorbing iron.
- The amount of the red blood pigment must be increased rapidly. This may be necessary, for example, in women in the third trimester of pregnancy.
- Chronic bleeding is present, usually due to hereditary diseases such as Osler’s disease.
What causes too much iron?
It is possible to have too much iron circulating in the body. Doctors call this haemochromatosis, iron retention disease. In most cases, genetics are to blame: the body retains too much iron due to a genetic defect.30 Other causes are rare, including liver disease and impaired blood formation.31 People who receive blood donations also sometimes develop excess iron.32
An excess of iron can cause symptoms that affect the entire body, such as a bronze colouration of the skin. It also increases the risk of diseases such as:30
- Liver diseases
- Cardiac arrhythmias
- Type 2 diabetes
Bloodletting can help control an excessive iron condition. The doctor takes 500 millilitres of blood once or twice a week to empty the iron reserves. If iron levels fall, blood samples can be collected less frequently. Nevertheless, the treatment must be carried out for life.30
Iron deficiency – at a glance
What is iron?
Iron is a vital trace element, which humans must ingest through food. Our body needs iron to form the red blood pigment haemoglobin and to supply the cells with oxygen.
What happens if you have an iron deficiency?
If there is a permanent lack of iron in your body, you may experience symptoms of anaemia – iron deficiency anaemia. The consequences can range from paleness, headaches and fatigue to hair loss and brittle nails.
Who is affected by iron deficiency?
Women require more iron than men because they regularly lose iron during their menstrual period. Risk groups that often suffer from iron deficiency are pregnant women, nursing mothers, senior citizens, newborns and children, alcoholics, vegetarians, vegans, people with diseases of the gastrointestinal tract and competitive athletes.
Which foods contain iron?
Iron can be found in meat, offal and eggs as well as in plant-based foods such as whole-grain cereals, legumes, spinach and kale. However, the human body can absorb iron from animal foods significantly better. You can support the intestine in the utilisation of plant-based iron by combining it with vitamin C.
What should I do if I have an iron deficiency?
If you are slightly deficient in iron, it is usually enough to change your diet and consume more iron-containing foods. If the deficiency is severe or intestinal absorption is impaired, iron supplements can replenish the empty reserves.
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- Park SY, Na SY, Kim JH, Cho S, Lee JH. Iron Plays a Certain Role in Patterned Hair Loss. J Korean Med Sci. 2013;28(6):934-938. doi:10.3346/jkms.2013.28.6.934
- Wright JA, Richards T, Srai SKS. The role of iron in the skin and cutaneous wound healing. Front Pharmacol. 2014;5. doi:10.3389/fphar.2014.00156
- Cherayil BJ. Iron and immunity: immunological consequences of iron deficiency and overload. Arch Immunol Ther Exp (Warsz). 2010;58(6):407-415. doi:10.1007/s00005-010-0095-9
- Consumer advice center. Eisen: Quality not quantity is the question. https://www.verbraucherzentrale.de/wissen/lebensmittel/nahrungsergaenzungsmittel/eisen-qualitaet-nicht-quantitaet-ist-die-frage-8026. Published April 25, 2018. Accessed April 25, 2018.
- Dupont C. [Prevalence of iron deficiency]. Arch Pediatr Organe Off Soc Francaise Pediatr. 2017;24(5S):5S45-45S48. doi:10.1016/S0929-693X(17)24009-3
- German Nutrition Society. Eisen. https://www.dge.de/wissenschaft/referenzwerte/eisen/. Published April 25, 2018. Accessed April 25, 2018.
- Office of Dietary Supplements - Iron. https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/. Accessed May 11, 2018.
- Kasper H. Nutritional Medicine And Dietetics. 12th ed. Urban & Fischer Verlag/Elsevier GmbH; 2014.
- Pregnancy: Iron prevents deficient births. https://www.aerzteblatt.de/nachrichten/54900/Schwangerschaft-Eisen-verhindert-Mangelgeburten. Published April 25, 2018. Accessed April 25, 2018.
- Iron intake in small children in Europe is sometimes too low. https://www.ernaehrungs-umschau.de/news/12-02-2015-eisenaufnahme-bei-kleinkindern-in-europa-teilweise-zu-gering/. Published April 25, 2018. Accessed April 25, 2018.
- Daniells S, Hardy G. Hair loss in long-term or home parenteral nutrition: are micronutrient deficiencies to blame?: Curr Opin Clin Nutr Metab Care. 2010;13(6):690-697. doi:10.1097/MCO.0b013e32833ece02
- Hempel EV, Bollard ER. The Evidence-Based Evaluation of Iron Deficiency Anemia. Med Clin North Am. 2016;100(5):1065-1075. doi:10.1016/j.mcna.2016.04.015
- Iron Deficiency and Iron Deficiency Anemia - Onkopedia. https://www.onkopedia.com/de/onkopedia/guidelines/eisenmangel-und-eisenmangelanaemie/@@view/html/index.html. Published April 25, 2018. Accessed April 25, 2018.
- Murawska N, Fabisiak A, Fichna J. Anemia of Chronic Disease and Iron Deficiency Anemia in Inflammatory Bowel Diseases: Pathophysiology, Diagnosis, and Treatment. Inflamm Bowel Dis. 2016;22(5):1198-1208. doi:10.1097/MIB.0000000000000648
- Freeman HJ. Iron deficiency anemia in celiac disease. World J Gastroenterol WJG. 2015;21(31):9233-9238. doi:10.3748/wjg.v21.i31.9233
- Cappellini MD, Comin‐Colet J, de Francisco A, et al. Iron deficiency across chronic inflammatory conditions: International expert opinion on definition, diagnosis, and management. Am J Hematol. 2017;92(10):1068-1078. doi:10.1002/ajh.24820
- Mei Z, Cogswell ME, Looker AC, et al. Assessment of iron status in US pregnant women from the National Health and Nutrition Examination Survey (NHANES), 1999-2006. Am J Clin Nutr. 2011;93(6):1312-1320. doi:10.3945/ajcn.110.007195
- Cantor AG, Bougatsos C, Dana T, Blazina I, McDonagh M. Routine iron supplementation and screening for iron deficiency anemia in pregnancy: a systematic review for the U.S. Preventive Services Task Force. Ann Intern Med. 2015;162(8):566-576. doi:10.7326/M14-2932
- Clénin G, Cordes M, Huber A, et al. Iron deficiency in sports – definition, influence on performance and therapy. Swiss Med Wkly. 2015;145(4344). doi:10.4414/smw.2015.14196
- Burden RJ, Pollock N, Whyte GP, et al. Effect of Intravenous Iron on Aerobic Capacity and Iron Metabolism in Elite Athletes. Med Sci Sports Exerc. 2015;47(7):1399-1407. doi:10.1249/MSS.0000000000000568
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