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Anaemia, iron deficiency

 

Iron deficiency anaemia occurs when there is a reduced number of red blood cells because the body does not have enough iron to produce them. The main symptoms are tiredness and lethargy (lack of energy).

Anaemia

There are several different types of anaemia and each one has a different cause. The most common type of anaemia is iron deficiency anaemia, which this article focuses on.

Other forms of anaemia can be caused by a lack of vitamin B12 or folate in the body.

See the Health A-Z topic about Vitamin B12 and folate deficiency anaemia for more information about this condition.

Iron

Iron is found in meat, dried fruit and some vegetables. It is used by the body to make haemoglobin, which helps store and carry oxygen in red blood cells (see box, left).

Haemoglobin transports oxygen from the lungs to the rest of the body. If there is a lack of iron in the blood, the organs and tissues will not get as much oxygen as they usually do.

How common is iron deficiency anaemia?

Iron deficiency anaemia affects up to 1 in 20 men and 1 in 20 post-menopausal women (after a woman's menstrual periods have stopped).

Iron deficiency anaemia is more common in women who are still menstruating (having periods). This is because menstruation and pregnancy can cause iron deficiency.   

Outlook

Treatment for iron deficiency anaemia involves increasing dietary iron intake or taking iron supplements to replace the missing iron in the body. This is usually very effective and the condition rarely causes any serious complications.

If you have iron deficiency anaemia, you may need to be monitored to check that the treatment is working and that your iron levels have returned to normal.

In some cases, further tests may be necessary to determine the underlying cause of your iron deficiency anaemia. Apart from menstrual loss, the most common cause is bleeding in the gastrointestinal tract (the stomach and intestines), which may require separate treatment.

Blood
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Bone marrow
Bone marrow is the soft, spongy tissue in the centre of bones that produces blood cells.

Deficiency
If you have a deficiency, you are lacking in a particular substance needed by the body.

Intestines
The intestines are part of the digestive system, between the stomach and the anus, which digest and absorb food and liquid.

Plasma
Plasma is the liquid part of blood, which holds other blood cells together.

Stomach
The sac-like organ of the digestive system. It helps digest food by churning it and mixing it with acids to break it down into smaller pieces.

 

Anaemia occurs when there is a reduced number of red blood cells. This can be caused by an iron deficiency.

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.

Haemoglobin

Haemoglobin acts as a sort of transport mechanism for the blood. As blood passes through the lungs, the haemoglobin pulls in oxygen molecules and releases carbon dioxide molecules.

After moving away from the lungs, the haemoglobin delivers the oxygen molecules to the body’s tissue and absorbs any excess carbon dioxide molecules to take back to the lungs.

Bone marrow

Red blood cells, which contain haemoglobin, are produced in the bone marrow (a red spongy material that is found inside the larger bones). Millions of new cells are produced every day to replace old cells that break down.

Nutrients from food, such as iron and certain vitamins, ensure that your bone marrow remains healthy and is able to produce a constant supply of red blood cells.

The most common symptoms of iron deficiency anaemia include:

  • tiredness
  • lethargy (lack of energy)
  • shortness of breath (dyspnoea)
  • palpitations (irregular heartbeat)

Less common symptoms of iron deficiency anaemia include:

  • headache
  • tinnitus, the perception of a noise in one or both ears or in your head that comes from inside your body, such as a ringing in your ears
  • an altered sense of taste
  • pica, a desire to eat non-food items, such as ice, paper or clay
  • a sore tongue
  • feeling itchy
  • difficulty swallowing (dysphagia)

Changed appearance

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

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

Slow-developing symptoms

Many people with iron deficiency anaemia will only display a few signs or symptoms of the illness. For example, you may only notice tiredness or shortness of breath after running up the stairs.

The severity of your symptoms may depend on how quickly your anaemia develops. For example, you may notice very few symptoms or they may develop gradually if your anaemia is caused by a chronic (long-term) slow loss of blood, such as a stomach ulcer (an open sore that develops on the inside lining of your stomach).

Deficiency

If you have a deficiency, you are lacking in a particular substance needed by the body.

Stomach

The sac-like organ of the digestive system. It helps digest food by churning it and mixing it with acids to break it down into smaller pieces.

Ulcers

An ulcer is a sore break in the skin or on the inside lining of the body.

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 are outlined below.

Gastrointestinal blood loss

Your gastrointestinal tract is the part of your body responsible for digesting food. It is made up of the:

  • stomach, a sac-like organ that helps digest food by churning it and mixing it with acids to break it down into smaller pieces
  • intestines, which digest and absorb food and liquid

Bleeding in the stomach and intestines is the most common cause of iron deficiency anaemia in men and in women who have been through the menopause (when a woman's monthly periods stop).

Some of the causes of gastrointestinal bleeding are outlined below.

Non-steroidal anti-inflammatory drugs (NSAIDs)

If used in high doses for a prolonged period of time, non-steroidal anti-inflammatory drugs (NSAIDs) can sometimes cause bleeding in the stomach. Ibuprofen and aspirin are two commonly prescribed NSAIDs.

If your GP suspects that your medication is causing gastrointestinal bleeding, they may be able to prescribe an alternative medicine that is less harmful to your stomach and intestines. Do not stop taking a medicine that has been prescribed for you 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 (an open sore). This is also known as a peptic ulcer.

Occasionally, a stomach ulcer can cause your stomach lining to bleed. In some cases, this may cause you to vomit blood or to pass blood in your stools (faeces). However, if the ulcer is slow bleeding, you may not have these symptoms. Either way, the blood loss from your stomach can result in you developing anaemia.

See the Health A-Z topic about Peptic ulcer for more information about this condition.

Cancer

In some rare cases, gastrointestinal bleeding can be caused by cancer, usually of the stomach or colon (part of the bowel, which makes up the digestive system). About 450 cases of stomach cancer are diagnosed in Ireland each year.

In diagnosing the cause of your anaemia, your GP will check for any possible signs of cancer. If your GP suspects you may have cancer, you will be immediately referred to a gastroenterologist (a specialist in treating conditions of the digestive system) for a more thorough examination. This way, if cancer is found, it can be diagnosed and treated as quickly as possible.

See the Health A-Z topics about Stomach cancer and Bowel cancer for more information about these conditions.

Angiodysplasia

Gastrointestinal bleeding can also be caused by a condition called angiodysplasia. This is an abnormality of the blood vessels in the gastrointestinal tract that can cause bleeding.

Causes in women

In women who are still menstruating (having monthly periods), the most common causes of iron deficiency anaemia are:

  • menstruation (monthly periods)
  • pregnancy

These are described in more detail below. 

Menstruation

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.

See the Health A-Z topic about Heavy periods for more information about this condition.

Pregnancy

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.

Other causes

Other conditions or situations that cause blood loss and may lead to iron deficiency anaemia include:

  • inflammatory bowel disease: a condition that causes inflammation (redness and swelling) in the digestive system, such as Crohn's disease and ulcerative colitis 
  • oesophagitis: inflammation of the gullet (oesophagus) that is caused by stomach acid leaking up it
  • schistosomiasis: an infection that is caused by parasites and is mainly found in sub-Saharan Africa
  • blood donation: donating a large amount of blood may lead to anaemia
  • trauma: a serious accident, such as a car accident, may cause you to lose a lot of blood 
  • nosebleeds: if you have a lot of nosebleeds, this may lead to anaemia, although it is rare
  • haematuria (blood in your urine): this is also rare and may be the symptom of another condition

Malabsorption

Malabsorption (when your body cannot absorb the iron from your food) is another possible cause of iron deficiency anaemia. This may occur if you have:

  • coeliac disease, a condition that damages the lining of the intestines
  • a gastrectomy, a medical procedure to surgically remove your stomach, for example to treat stomach cancer

Diet

Unless you are pregnant, it is very rare for iron deficiency anaemia to be caused solely by a lack of iron in your diet.

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


Blood vessel
Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.

Deficiency
If you have a deficiency, you are lacking in a particular substance needed by the body.

Inflammation
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.

Intestines
The intestines are part of the digestive system, between the stomach and the anus, which digest and absorb food and liquid.

Stomach
The sac-like organ of the digestive system. It helps digest food by churning it and mixing it with acids to break it down into smaller pieces.

Ulcers
An ulcer is a sore break in the skin or on the inside lining of the body.

See your GP if you experience symptoms of iron deficiency anaemia. A blood test will be able to confirm the diagnosis. Your GP may also ask you a number of questions and carry out a physical examination to find out the cause of your anaemia.

Blood test

To diagnose iron deficiency anaemia, a blood sample will be taken from a vein in your arm and a full blood count will be made. This means that all the different types of blood cells in the sample will be measured.

If you have iron deficiency anaemia:

  • you will have lower levels of haemoglobin (a protein that transports oxygen) than normal
  • you will have fewer red blood cells (cells that contain haemoglobin) than normal
  • your red blood cells may be smaller and paler than usual

Your GP may also test for a substance called ferritin, a protein that stores iron. If your ferritin levels are low, you do not have much iron stored in your body and you may have iron deficiency anaemia.

Vitamin B12 and folate

If your GP suspects that your anaemia may be due to a vitamin B12 and folate deficiency, rather than an iron deficiency, your levels of these substances may be tested. Folate works with vitamin B12 to help your body produce red blood cells.

Vitamin B12 and folate deficiency anaemia is more common in people who are over 75 years of age.

See the Health A-Z topic about Vitamin B12 and folate deficiency anaemia for more information about this condition.

Finding the cause

To determine the underlying cause of your anaemia, your GP may ask you a number of questions about your lifestyle and medical history. For example, you may be asked questions about the following areas:

  • your diet, to see what you typically eat and whether this includes any iron-rich foods
  • any medicines that you take, to see whether you have been regularly taking a type of medicine that can cause gastrointestinal bleeding (bleeding from the stomach and intestines), such as ibuprofen or aspirin
  • your menstrual pattern: if you are a woman, your GP may ask if you have been experiencing particularly heavy periods (menorrhagia)
  • your family history: you will be asked whether any of your immediate family has anaemia or a history of gastrointestinal bleeding or blood disorders
  • blood donation: your GP will want to know whether you regularly donate blood or if you have a history of excessive bleeding
  • other medical conditions: your GP may ask whether you have recently had another illness or experienced any other symptoms, such as weight loss

Physical examination

Your GP may want to carry out a physical examination to try to confirm what is causing your iron deficiency anaemia. This will usually only be necessary if an obvious cause for your iron deficiency anaemia has not been found.

Your GP may:

  • examine your abdomen (stomach) as gastrointestinal bleeding is a common cause of anaemia
  • look for signs of heart failure (when your heart is not pumping blood around your body very efficiently), such as swollen ankles, as the main symptom of heart failure is extreme tiredness 

Two other possible types of physical examination that you may have are explained below.

Rectal examination

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

A rectal examination is not something to be embarrassed about as it is a procedure that your GP will be very used to performing. 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 be advised to have a pelvic examination if their GP suspects that 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 examine you internally. This will involve your GP inserting gloved, lubricated fingers into your vagina to feel whether your ovaries and uterus (womb) are tender or enlarged.

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

Pregnancy

As iron deficiency anaemia is common during pregnancy, if you have the condition while you are pregnant, your GP will not usually 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.

Referral

Your GP may refer you to a gastroenterologist (a specialist in treating conditions of the digestive system), who will be able to carry out a more thorough examination, if, for example:

  • your GP detected an abnormality during a rectal examination
  • you are anaemic and have experienced sudden or unexplained weight loss
  • you are a woman who is not menstruating (having periods) and who has a very low haemoglobin level

It is very important to see a specialist if your GP recommends it. This will enable any more serious conditions to be diagnosed as soon as possible.

For example, 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 heavy periods (menorrhagia), you may be referred to a gynaecologist if you fail to respond to treatment with iron supplements.

Deficiency
If you have a deficiency, you are lacking in a particular substance needed by the body.

Red blood cells
Red blood cells transport oxygen around the body.

Stomach
The sac-like organ of the digestive system. It helps digest food by churning it and mixing it with acids to break it down into smaller pieces.

Intestines
The intestines are part of the digestive system, between the stomach and the anus, which digest and absorb food and liquid.

Treatment for iron deficiency anaemia usually involves taking iron supplements to replace the missing iron and making any necessary changes to address the underlying cause. 

Iron supplements

Your GP will prescribe an iron supplement to restore the iron that is missing from your body. The most commonly prescribed supplement is ferrous sulphate, which is taken orally (by mouth) two or 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 and can cause:

  • nausea (feeling sick)
  • sickness
  • abdominal (tummy) pain
  • heartburn
  • constipation (feeling unable to empty your bowels)
  • diarrhoea
  • black stools (faeces)

These side effects should settle down over time. Taking ferrous sulphate with food or shortly after eating may help to minimise any side effects. Your GP may also recommend that you only take one or two tablets a day, instead of three, if you are finding the side effects difficult to cope with. 

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

Storing iron supplements

If you have young children, it is very important to store your iron supplements out of their reach. This is because an overdose of iron supplements in a young child has a toxic effect, which can be fatal.

Dietary advice

If a lack of iron in your diet is thought to contribute to your iron deficiency anaemia, your GP will advise you how to include more iron in your diet.

Iron-rich foods include:

  • meat
  • dark-green leafy vegetables, such as watercress and curly kale
  • iron-fortified bread
  • beans
  • nuts
  • apricots
  • prunes
  • raisins

To ensure you have a healthy, well-balanced diet, include foods from all the major food groups in your diet. If you have iron deficiency anaemia, eat plenty of iron-rich foods, such as those listed above.

Some foods and medicines can make it harder for your body to absorb iron. These may include:

  • tea and coffee
  • wholegrain cereals
  • calcium, found in dairy products such as milk
  • antacids (medication to help relieve indigestion)
  • proton pump inhibitors (PPIs), which affect the production of acid in your stomach

If you are finding it difficult to include iron in your diet, you may be referred to a dietitian (a health professional who specialises in nutrition). They can give you more detailed, personalised guidance about how you can change your diet.

Underlying causes

Your GP will also need to ensure that the underlying cause of your anaemia is treated so that anaemia 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 different ways, using both medicines and special internal devices.

If you have been diagnosed with another condition as well as iron deficiency anaemia, see the relevant Health A-Z topic to find out how it will be treated.

Continuing treatment

In some people, after the iron stores in the body have been replenished, they start to fall again.

In these circumstances, you may be prescribed an ongoing iron supplement. This will usually take the form of one tablet a day. This will prevent you from becoming iron deficient and will stop your anaemia returning. 

If treatment fails

If your iron levels do not improve, your GP will ask you how regularly you have been taking your iron supplements. Some people are put off taking the medication because of the side effects (see above). However, 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 still not improved, your GP may refer you for an assessment with a specialist.

Deficiency
If you have a deficiency, you are lacking in a particular substance needed by the body.

Red blood cells
Red blood cells are cells in the blood that transport oxygen around the body.

Stomach
The sac-like organ of the digestive system. It helps digest food by churning it and mixing it with acids to break it down into smaller pieces.

 

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

Tiredness

As iron deficiency anaemia can leave you tired and lethargic (lacking in energy), you may be 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 (the body's natural defence system), making you more susceptible to illness and infection.

Heart and lung complications

Adults with severe anaemia may be at risk of developing complications that affect their heart or lungs. For example, you may develop:

  • tachycardia (an abnormally fast heartbeat)
  • heart failure, when your heart is not pumping blood around your body very efficiently

Pregnancy

Pregnant women with severe anaemia have an increased risk of developing complications, particularly during and after the birth. They may also develop postnatal depression (a type of depression that some women experience after having a baby).

Research suggests that babies born to mothers who have anaemia are more likely to:

  • be born prematurely (before week 37 of the pregnancy)
  • have a low birth weight
  • have problems with their iron levels
  • do less well in mental ability tests

Deficiency
If you have a deficiency, you are lacking in a particular substance needed by the body.

Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.


Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.