Iron deficiency anaemia
You need iron for many important processes inside your body, especially for making haemoglobin - the oxygen-carrying protein in your blood.
This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.
You need iron for many important processes inside your body, especially for making haemoglobin - the oxygen-carrying protein in your blood.
Iron is absorbed from your food and drink by your bowel. It's carried in your blood to your bone marrow, where blood cells are produced. Here, the iron is combined with proteins to make haemoglobin. Spare iron can be stored in your liver.
On average, men need 8.7mg of iron a day and women need 14.8mg a day. You can usually get all the iron you need from your diet.
Small amounts of iron are lost from your body in urine, faeces and dead skin cells. Much more is lost if you lose blood.
If you have a shortage, or deficiency, of iron in your body, your bone marrow will make small red blood cells that don't contain enough haemoglobin. These red blood cells can't carry enough oxygen to your organs and tissues. This leads to the symptoms of anaemia.
Certain groups of people are more likely to have iron-deficiency anaemia. These include babies, teenagers and women who have heavy periods.
The symptoms of iron-deficiency anaemia include:
- feeling breathless after little exercise
- feeling tired
- palpitations (the sensation of feeling the heartbeat thumping in the chest)
- looking pale
- a rapid pulse
Less common symptoms can include:
- tinnitus (ringing in your ears)
- an altered sense of taste
- brittle nails or 'spoon nails' where the middles of your nails are pushed inwards and the edges are raised
- soreness at the edges of your mouth
- a short attention span and poor concentration
These symptoms aren't always due to iron-deficiency anaemia but if you have them, see your GP.
If iron-deficiency anaemia isn't treated, there are a range of possible complications. For example in adults, it can affect your ability to work and exercise. It can also increase your risk of heart problems. Ask your GP for more information.
Loss of blood
Iron-deficiency anaemia is usually caused by heavy bleeding, such as from an injury or after an operation. A common cause of iron-deficiency anaemia in women is bleeding from heavy periods.
You're more likely to develop iron-deficiency anaemia if you:
- take aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) as these can cause stomach bleeding
- have problems with your digestive system that may lead to bleeding in your stomach or bowel
Diet and digestion
You may develop an iron-deficiency anaemia if you don't get enough iron in your diet, or if the iron in your diet isn't absorbed properly.
A healthy diet including meat contains enough iron for most adults. Red meat is the richest source of iron and the iron is easily absorbed by your body. If you follow a vegetarian or vegan diet, you may not be able to get enough iron. This is because, although you can get iron from foods such as pulses, green leafy vegetables and nuts, the iron in these foods isn't absorbed so easily.
Conditions that affect your digestive system can cause iron-deficiency anaemia. For example, coeliac disease damages the lining of your small bowel and prevents the normal absorption of nutrients, including iron. If you have surgery on your stomach or small bowel, this can also affect your absorption of iron.
It's very common for women to develop iron-deficiency anaemia during pregnancy because their unborn baby needs iron and takes its supply from its mother. Iron deficiency is more likely to develop during pregnancy in women whose diet doesn't contain plenty of iron.
Children and toddlers may develop iron-deficiency anaemia because growth spurts take up extra iron.
Occasionally, in women over 40, iron deficiency is part of a condition called Plummer Vinson syndrome. This condition makes it difficult for you to swallow as it causes small web-like growths to develop in your oesophagus (the pipe that goes from your mouth to your stomach).
Your GP will ask about your symptoms and examine you. He or she may also ask you about your medical history.
Your GP will ask you to have a blood test. Your blood sample will be sent to a laboratory for testing, including a full blood count (FBC) to give information about your haemoglobin level and how many of each of the different types of blood cells you have. A FBC also gives information about the size of your red cells and the amount of haemoglobin each one contains.
The normal amount - or concentration - of haemoglobin is:
- at least 13g/dl (13 grams of haemoglobin per decilitre of blood - a decilitre is 100ml) for men
- at least 11.5g/dl for women
- at least 11g/dl for pregnant women
The values for children vary by age - ask your GP for more advice.
If your haemoglobin level is low, and your red cells are small, you may have iron-deficiency anaemia. You may need to have other blood tests, such as a ferritin test, which can give an idea of how much iron is in your body.
Depending on the suspected cause of iron-deficiency anaemia, your GP may refer you to one of the following doctors for further tests.
- A haematologist (a doctor who specialises in treating blood disorders).
- A gastroenterologist (a doctor who specialises in conditions of the digestive system).
- A gynaecologist (a doctor who specialises in women's reproductive health).
Your doctor will first try to identify why you're deficient in iron so that the cause can be treated.
You may need to improve your diet so that it includes more iron. Your doctor may refer you to a dietitian for advice on how to do this.
Your doctor may prescribe iron supplements, such as ferrous sulphate tablets. Iron supplements make up for the shortage of iron and will then build up your body's stores of iron to the normal level. You will usually need to take tablets two to three times a day for up to seven months. Always read the patient information leaflet that comes with your medicine and ask your GP or pharmacist for advice if you have any questions.
Iron supplements can have side-effects. These include feeling sick, heartburn, constipation and diarrhoea. They can also cause your faeces to turn black. These side-effects may be reduced if you take the tablets after meals.
If you have another problem, such as blood loss, you may need treatment for this as well as a course of iron tablets.
You can reduce your risk of developing iron-deficiency anaemia by eating a healthy, balanced diet that contains plenty of iron.
Good sources of iron include:
- green vegetables
- dried fruit
- pulses, such as chick peas and lentils
- foods that are fortified with iron, such as some breakfast cereals and bread (fortified means that iron has been added during manufacturing)
It's thought that vitamin C might help you to absorb iron, so if you have a glass of orange juice with your meal it may help to improve your levels of iron. You could also eat foods containing vitamin C at the same time as eating foods containing iron. Good sources of vitamin C include peppers, sweet potatoes, oranges and kiwi fruit.
What you drink affects how your body will absorb iron. Tea and coffee contain substances called polyphenols that can bind with iron and make it harder for your body to absorb it. If you cut down on the amount of tea and coffee it could help to improve iron levels in your body.
Iron is stored in your body and too much iron can be harmful. Only take iron supplements if your doctor recommends it.
Will my iron-deficiency anaemia need to be monitored? How often should I go back to see my GP?
Once you have been diagnosed with iron-deficiency anaemia and started treatment, you will need to go back to your GP for further blood tests to make sure that your blood count and iron levels have returned to normal.
The most common treatment for iron-deficiency anaemia is a course of iron tablets, such as ferrous sulphate tablets. You should take the tablets as directed by your GP - usually, you will need to take them two to three times a day. Always read the patient information leaflet that comes with your medicine, and if you have any questions ask your GP for advice.
You will be asked to return to your GP two to four weeks after starting your iron tablets for a blood test, to check that they are working. You will then need to return two to four months later to make sure that your haemoglobin level has returned to normal.
Once your GP is happy that your blood count is normal, you will usually need to continue taking your tablets for a further three months. This is to make sure that your body's iron stores are completely topped up. Once you have stopped taking your tablets, you will need to return to your GP for a blood test after a few months. If your blood count and iron level have fallen again, you will be given another course of iron tablets.
If the iron tablets prescribed by your GP aren't working, you may be referred to a haematologist for further investigation. A haematologist is a doctor who specialises in treating blood disorders. It's very important to understand why you have iron-deficiency anaemia because it's usually caused by blood loss. In women, this is most often through heavy periods, but in men and older women it's possible that there is bleeding from your stomach or bowel, so this must be investigated.
If you have any questions or concerns about iron tablets or iron-deficiency anaemia, talk to your GP.
I get an upset stomach when I take iron tablets, what should I do?
Some people find that they get an upset stomach when taking iron tablets, but it's important to continue taking the tablets as directed by your doctor if at all possible. If you need to, you can take over-the-counter medicines to ease your stomach symptoms until they settle by themselves.
When taking iron supplements, some people find that their digestive system is disturbed. This can cause:
- stomach pain
- constipation or diarrhoea, often with black faeces
Usually these symptoms settle down quickly, so there is no need to stop taking your tablets. In the meantime, there are medicines you can buy from your pharmacy to relieve your symptoms, for example, antacids for heartburn or medicines for constipation.
You could also try taking your tablets with or after food rather than on an empty stomach, and as one daily dose instead of spreading them out through the day.
It's important to follow your GP's advice and keep taking your iron tablets as directed. If they are causing you a lot of discomfort and your symptoms don't settle, go back to see your GP before you stop taking them. He or she will be able to advise you on alternative brands or formulations to try.
I've heard that taking too many iron tablets can be harmful, why is this?
Taking a large number of iron tablets at one time is extremely dangerous, and can be fatal. It can damage your gut and liver and cause heart failure. Taking iron tablets over a long period of time when you don't need to can also be harmful.
Taking too many iron tablets is harmful to your body for two reasons. First, it can damage your gut, and secondly, it can harm organs such as your heart and liver and may cause irreversible damage.
If you have taken too many iron tablets, you must go to hospital as quickly as possible - an iron overdose is a medical emergency. Treatment is best started within one hour of taking the tablets, so it's important to take immediate action.
Iron overdose is the most common type of childhood poisoning, usually happening when children take tablets meant for adults. Iron tablets are often brightly coloured and sugar-coated, so can be mistaken as sweets by children. It's extremely important to make sure that all medicines and tablets are kept out of the reach of children.
If you take a normal dose of iron tablets over a long period of time when you don't need them, this can also be harmful. Iron can build up in various organs, such as your liver, pancreas and heart, and eventually cause damage. It's particularly important to avoid taking unnecessary iron tablets if you have certain inherited conditions such as genetic haemochromatosis or thalassaemia.
Always read the patient information leaflet that comes with your medicine and follow the recommended dose, unless you have been instructed otherwise by your doctor.
If you have any questions or concerns about iron overdose, talk to your GP.
What is hookworm infection and how does it cause iron-deficiency anaemia?
Hookworm infection occurs when a parasitic worm (hookworm) gets into your gut and feeds from the wall of your bowel. This may result in blood loss and is a common cause of iron deficiency in certain parts of the world, such as the tropics.
Hookworms are parasitic worms that you can pick up from eating contaminated foods or through your skin, usually the soles of your feet. They are commonly found in developing, tropical countries. It's estimated that over 740 million people in the world have a hookworm infection.
Once inside your body, the hookworms pass into your lungs. They are then coughed up and swallowed down into your gut (gastrointestinal tract). Once there, they attach themselves to the wall of your bowel and feed on your blood.
Most hookworm infections are mild and there are usually no symptoms. However, if the infection is more severe, the blood lost from your gut (sucked by the worms) can lead to iron-deficiency anaemia. Other symptoms can include an allergic reaction in a specific part or all over your body, and stomach pain. These symptoms can be caused by many conditions, not just hookworm. It's important that you see your GP to get the correct diagnosis.
Once your GP has examined you and asked about your symptoms, he or she will ask you for a sample of faeces. This is because, once in your bowel, hookworms pass their eggs out through your faeces. You will also be asked to have a blood test. These will both be sent to a laboratory for testing. Once diagnosed, your GP may refer you to a doctor who specialises in treatment of tropical diseases.
Treatment of a hookworm infection is with a medicine called mebendazole. You will need to take it twice daily for three days. You will also need treatment for your iron-deficiency anaemia. This is usually a course of iron tablets, such as ferrous sulphate tablets. Always ask your doctor for advice and read the patient information leaflet that comes with your medicine.
If you have any questions or concerns about hookworm infection or iron-deficiency anaemia, talk to your GP.
- British Nutrition Foundation
020 7404 6504
- Anaemia – iron deficiency. Prodigy. www.prodigy.clarity.co.uk, published July 2011
- Anaemia. Lab Tests Online UK. www.labtestsonline.org.uk, published January 2010
- Goddard AF, James MW, McIntyre AS, et al. Guidelines for the management of iron deficiency anaemia. Gut 2011; 60:1309–16. doi:10.1136/gut.2010.228874
- The ferritin test. Lab Tests Online UK. www.labtestsonline.org.uk, published May 2004
- Iron overdose. The Merck Manuals. www.merckmanuals.com, published January 2009
- Haemoglobin and iron. The National Blood Service.www.blood.co.uk, published July 2008
- Hookworm disease. National Institute of Allergy and Infectious Diseases. www.niaid.nih.gov, published September 2010
- Joint Formulary Committee. British National Formulary. 62nd ed. London: British Medical Association and Royal Pharmaceutical Society of Great Britain; 2011
- Hotez PJ, Brooker S, Bethony JM, et al. Hookworm infection. NEJM 2004; 351:799–807. www.nejm.org
- Personal communication, Dr John Houghton, Consultant Haematologist, Spire Manchester Hospital, 21 November 2011
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