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Anaemia, iron deficiency

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Anaemia is a condition that occurs when there is a reduced number of red blood cells or concentration of haemoglobin.

There are several different types of anaemia, and each one has a different cause. The most common form of the condition is iron-deficiency anaemia. This is where your body lacks enough iron to keep the red blood cells functioning properly.
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Iron is a key component of haemoglobin, the substance that helps to store and carry the oxygen in red blood cells. If there is a lack of iron in your blood, your organs and tissues will not get as much oxygen as they usually do.

Other forms of anaemia can be caused by a lack of vitamin B12 or folate in your body. This article concentrates on iron-deficiency anaemia.

Treatment for iron-deficiency anaemia is usually very effective, and the condition rarely causes any serious complications. Your blood may need to be monitored every few months after your diagnosis to check that you are responding to treatment and that your iron levels have returned to normal.

About the blood

Blood contains a fluid called plasma, which includes three different types of cells:

  • White blood cells are part of the body's immune system and defend it against infection.
  • Red blood cells carry oxygen around the body in a substance called haemoglobin.
  • Platelets help the blood to clot.

Red blood cells are produced in the bone marrow. Vast quantities (millions) of new cells are produced each day to replace old cells that break down. Nutrients from food, such as iron and certain vitamins, help ensure that your bone marrow remains healthy and is able to produce a constant supply of red blood cells.


Symptoms of anaemia

The most common symptoms of iron deficiency anaemia include:

  • tiredness,
  • lethargy,
  • shortness of breath (dyspnoea), and
  • palpitations (irregular heart beat).

Less common symptoms of iron deficiency anaemia include:

  • headache,
  • ringing in your ears (tinnitus),
  • an altered sense of taste,
  • a desire to eat non-food items, such as ice, paper, or clay (pica),
  • sore tongue, and
  • difficulty swallowing (dysphagia).

You may also notice changes in your physical appearance. For example, signs that you may have iron deficiency anaemia include:

  • pale complexion,
  • abnormally smooth tongue (atrophic glossitis),
  • painful ulcers on the corners of your mouth (angular chelosis),
  • dry, flaking nails, and
  • spoon-shaped nails.

Many people with iron deficiency anaemia will only display a few signs or symptoms of the illness. The severity of your symptoms may also depend on how quickly your anaemia develops. For example, if your anaemia is being caused by a chronic (long-term) slow loss of blood, such as a stomach ulcer, then you may notice very few symptoms, or they may develop gradually.


Causes of anaemia

Iron deficiency anaemia occurs when the body does not have enough iron.

A lack of iron in your body can be caused by a variety of factors. Some of these factors are outlined below.

Gastrointestinal blood loss

Your gastrointestinal tract is made up of your stomach and your intestines, and is the part of your body responsible for digesting food.

Bleeding in the stomach and intestines is the most common cause of iron deficiency anaemia in men, and is also the most common cause for women who have been through the menopause.

Some of the causes of gastrointestinal bleeding are outlined below.

Non-steroidal anti-inflammatory drugs (NSAIDs)

If used for a prolonged period of time, in high doses, NSAIDs can sometimes cause bleeding in the stomach. Ibuprofen and aspirin are examples of commonly prescribed NSAIDs.

If your GP suspects your medication is causing gastrointestinal bleeding, they may be able to prescribe you an alternative medicine which is less harmful to your stomach and intestines. However, you should never stop taking a medicine unless your GP specifically advises you to.

Stomach ulcers

Sometimes, the acid in your stomach (which usually helps your body to digest food) can eat into your stomach lining. When this happens, the acid forms an ulcer.

A stomach ulcer can occasionally cause your stomach lining to bleed. In some cases, this may cause you to vomit blood, or to pass blood in your stools. However, if the ulcer is slow-bleeding, you may not display these symptoms. Either way, the blood loss from the stomach can cause you to develop anaemia.


In some rare cases, gastrointestinal bleeding can be caused by cancer, usually of the stomach, or colon. This is why your GP will be very careful when diagnosing the cause of your anaemia, to check for any possible signs of cancer.

If your GP suspects that cancer may be a cause of your gastrointestinal bleeding, you will be immediately referred to a gastrointestinal specialist for a more thorough examination. This way, if cancer is found, it can be diagnosed and treated as quickly as possible.


Menstruation is the most common cause of iron deficiency anaemia in women who have yet to go through the menopause. Usually, only women with particularly heavy periods develop iron deficiency anaemia. If you have heavy bleeding over several consecutive menstrual cycles, it is known as menorrhagia.


It is very common for women to develop iron deficiency during pregnancy. This is because your body needs extra iron so that your baby has a sufficient blood supply, and receives all of the necessary oxygen and nutrients. Many pregnant women require an iron supplement, particularly from the 20th week of pregnancy.


Unless you are pregnant, it is very rare for iron deficiency anaemia to be caused solely by a lack of iron in your diet. People most at risk from iron deficiency anaemia, as a result of their diet, are elderly people and vegans. However, even the most iron-poor diets rarely cause iron deficiency anaemia.

Pregnant women may have to increase the amount of iron-rich food they consume during their pregnancy in order to help avoid iron deficiency anaemia.


Diagnosing anaemia

Blood test

To diagnose iron deficiency anaemia, a simple blood test will be used to measure the amount of haemoglobin and the number of red blood cells in your blood. If you have iron deficiency anaemia, you will have fewer red blood cells than normal in a given volume of blood. The cells may also be smaller than usual.

To help determine the underlying cause of your anaemia, your GP may ask you a series of questions regarding areas such those outlined below.

  • Diet - to see what you typically eat, and whether this includes any iron-rich foods.
  • Medicines - to see whether you have been regularly taking a type of medicine which can cause gastrointestinal bleeding (bleeding from the stomach and intestines) such as ibuprofen, or aspirin.
  • Menstrual pattern - a GP will ask female patients if they have been experiencing particularly heavy periods (menorrhagia).
  • Family history - you will be asked whether any of your immediate family have anaemia, or whether they have any history of gastrointestinal bleeding, or blood disorders.
  • Blood donation - your GP will want to know if you regularly donate blood, or if you have a history of excessive bleeding.

Physical examination

Your GP may also have to carry out a physical examination to help confirm what is causing your iron deficiency anaemia.

Rectal examination

A rectal examination is a very common procedure, and will help your GP to determine whether there is something in your gastrointestinal tract that may be causing bleeding. It will usually involve your GP inserting a gloved, lubricated finger into your rectum, so that they can feel for any abnormalities.

This type of examination is not something to be embarrassed about, as your GP will be very used to performing them. It should not cause you any significant pain or discomfort, and you will only usually feel a slight sensation that your bowels are moving around.

Pelvic examination

Women may have to undergo a pelvic examination if their GP suspects heavy menstrual bleeding (menorrhagia) may be the cause of their anaemia.

During a pelvic examination, your GP will examine your vulva and labia (external sex organs) for signs of bleeding or infection. They may also have to examine you internally. This will involve your GP inserting gloved, lubricated fingers into your vagina to feel whether your ovaries or uterus (womb) are tender or enlarged.

A pelvic examination will only be carried out by a health professional who is qualified to perform the procedure, such as a GP, or a gynaecologist (a specialist in the female reproductive system). This type of examination will not be carried out without your consent, and you will also have the option of having someone with you during the procedure.


As iron deficiency anaemia is common during pregnancy, if you have the condition while you are pregnant, your GP will not normally have to look for any other underlying causes. Your GP will only look for an alternative cause if your haemoglobin level is particularly low, or if your symptoms, or medical history, suggest that your anaemia may be caused by other factors.


If your GP detected an abnormality during a rectal examination, you may have to be referred to a gastrointestinal specialist (a doctor who specialises in treating conditions which affect your digestive system), who will be able to carry out a more thorough examination. You will also be referred to a gastrointestinal specialist if you are anaemic and have experienced sudden or unexplained weight loss.

Women who are not menstruating (having periods) and who have a very low haemoglobin level will also be referred to a gastrointestinal specialist.

It is very important that you see a specialist if you are advised to by your GP in order that any more serious conditions can be diagnosed as soon as possible. This is because, in rare cases, gastrointestinal bleeding can be caused by cancer. The earlier gastrointestinal cancer is detected, the sooner it can be treated and the greater your chances of making a full recovery.

If you are a woman with menorrhagia (heavy periods) you may have to be referred to a gynaecologist if you fail to respond to iron supplement treatment.


Treating anaemia

Iron supplements

Iron deficiency anaemia is usually treated by replacing the iron that is missing from your body.

Your GP will prescribe you an iron supplement to help restore the iron which is missing from your body. The most commonly prescribed supplement is ferrous sulphate. This supplement is taken orally, up to three times a day.

Most people will not experience any side effects when taking iron supplements. However, in some cases, ferrous sulphate may upset your stomach causing sickness, heartburn, constipation, and diarrhoea. This supplement can also turn your stools black. However, taking this medicine with, or shortly after, food will help to minimise any side effects.

If you find that ferrous sulphate is not suitable for you because of the side effects, you may be prescribed a different iron supplement known as ferrous gluconate. This supplement should produce fewer side effects because it contains a less concentrated dose of iron. However, this does mean it may take longer for the levels of iron in your body to be restored.

Safe storage of iron supplements

If you have young children, it is very important that you keep your iron supplements safely stored away, and out of their reach. This is because an overdose of iron supplements in a young child has a toxic effect and can be fatal.

Dietary advice

If a dietary lack of iron is thought to be contributing to your iron deficiency anaemia, then your GP will give you advice on ways that you can change your diet to include more iron.

Iron-rich foods include:

  • dark green leafy vegetables (such as spinach),
  • iron-fortified bread,
  • beans,
  • nuts,
  • meat,
  • apricots,
  • prunes, and
  • raisins.

To make sure that you have a healthy, well-balanced diet, you should include foods from all the major food groups in your diet. However, those with iron deficiency anaemia should also make sure that they eat plenty of iron-rich foods, such as those listed above.

If you are still struggling to include iron in your diet, you may be referred to a dietician. A dietician will be able to give you more detailed, personalised guidance about how you can change your diet.

Underlying causes

Your GP will also have to make sure that the underlying cause of your anaemia is treated, to help ensure that your condition does not become a recurrent problem.

For example, if non-steroidal anti-inflammatory drugs (NSAIDs) are causing bleeding in your stomach, your GP may prescribe an alternative type of medicine, which will help minimise the risk of stomach bleeding. Heavy periods (menorrhagia) can also be treated in a number of ways, using both medicines and special internal devices.


Your GP will ask you to return for a check up, two to four weeks after you have started taking your iron supplements. At this check-up, your GP will be able to assess whether you have responded to treatment. They will do this by taking a further blood test so that your haemoglobin levels can be checked again.

If your blood test shows an improvement, you will be asked to return in 2-4 months time for a further blood test to ensure that your haemoglobin levels have returned to normal.

Once your haemoglobin and red blood cell levels are normal, your GP will usually advise that you continue taking iron supplements for three months to help replenish the iron stores in your body. After this, depending on the cause of the iron deficiency anaemia, you should be able to stop taking the supplements. Your condition will then be monitored every three months for one year.

If your iron levels do not improve, your GP will ask you about how regularly you have been taking your iron supplements. Some people are put off from taking the medication because of the side effects (see 'iron supplements' above), but not taking the supplements will mean that your condition will not improve.

If you have been taking the supplements as prescribed, and your iron levels have not improved, your GP will refer you for an assessment with a specialist.


Complications of anaemia

Iron deficiency anaemia rarely causes any serious or long-term complications. However, some people with iron deficiency anaemia do find that it impacts on their daily life. Some of the more common complications are outlined below.


As iron deficiency anaemia can leave you tired and lethargic, you may find that you are less productive and active at work. Your ability to stay awake and focus can be reduced, and you may not feel able to exercise regularly.

Immune system

Research has shown that iron deficiency anaemia can affect your immune system, making you more susceptible to illness and infection.


Pregnant women who are severely anaemic are at increased risk of developing complications, particularly during and after the birth. Research suggests that babies born to anaemic mothers are more likely to be born prematurely, or have a low birth weight. Babies affected by iron deficiency anaemia, may also go onto suffer problems with their iron levels themselves.

Useful links

NHS Choices links

External links

This article was originally published by NHS Choices

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