Iron deficiency anaemia

19 min read

What is iron deficiency anaemia?

Iron deficiency anaemia is a condition where a lack of iron in the body leads to a reduction in the number of red blood cells.

Iron is used to produce red blood cells, which help store and carry oxygen in the blood. If you have fewer red blood cells than is normal, your organs and tissues won't get as much oxygen as they usually would.

There are several different types of anaemia, and each one has a different cause. Iron deficiency anaemia is the most common type.

Other types of anaemia can be caused by a lack of vitamin B12 or folate in the body – read more about

vitamin B12 and folate deficiency anaemia

Symptoms of iron deficiency anaemia

Many people with iron deficiency anaemia only have a few symptoms. The severity of the symptoms largely depends on how quickly anaemia develops.

You may notice symptoms immediately, or they may develop gradually if your anaemia is caused by a long-term problem, such as a stomach ulcer.

The most common symptoms include:

Less common symptoms include:

  • headache
  • hearing sounds that come from inside the body, rather than from an outside source (tinnitus)
  • an altered sense of taste
  • feeling itchy
  • a sore or abnormally smooth tongue
  • hair loss
  • a desire to eat non-food items, such as ice, paper or clay (pica)
  • difficulty swallowing (dysphagia)
  • painful open sores (ulcers) on the corners of your mouth
  • spoon-shaped nails

When to see your doctor

See your doctor if you experience symptoms of iron deficiency anaemia. They should be able to diagnose the condition using a simple blood test .

Read more about

diagnosing iron deficiency anaemia

What causes iron deficiency anaemia?

There are many things that can lead to a lack of iron in the body. In men and post-menopausal women, the most common cause is bleeding in the stomach and intestines.

This can be caused by a stomach ulcer, stomach cancer, bowel cancer, or by taking

non-steroidal anti-inflammatory drugs (NSAIDs)

In women of reproductive age,

heavy periods
and pregnancy are the most common causes of iron deficiency anaemia as your body needs extra iron for your baby during pregnancy.

Unless you're pregnant, it's rare for iron deficiency anaemia to be caused just by a lack of iron in your diet. However, if you do lack dietary iron, it may mean you're more likely to develop anaemia than if you have one of the problems mentioned above.

Read more about the

causes of iron deficiency anaemia

How iron deficiency anaemia is treated

Treatment for iron deficiency anaemia involves taking iron supplements to boost the low levels of iron in your body. This is usually effective, and the condition rarely causes long-term problems.

You'll need to be monitored every few months to check the treatment is working and your iron levels have returned to normal.

The underlying cause will need to be treated so you don't get anaemia again. Increasing the amount of iron in your diet may also be recommended.

Good sources of iron include:

  • dark-green leafy vegetables, such as watercress and curly kale
  • iron-fortified cereals or bread
  • brown rice
  • pulses and beans
  • nuts and seeds
  • meat, fish and tofu
  • eggs
  • dried fruit, such as dried apricots, prunes and raisins

Read more about

treating iron deficiency anaemia

Further problems

If iron deficiency anaemia is left untreated, it can make you more susceptible to illness and infection, as a lack of iron affects the body's natural defence system (the immune system).

Severe iron deficiency anaemia may increase your risk of developing complications that affect the heart or lungs, such as an abnormally fast heartbeat (tachycardia) or

heart failure
, where your heart is unable to pump enough blood around your body at the right pressure.

Pregnant women with severe or untreated anaemia also have a higher risk of complications before and after birth.

Read more about the

complications of iron deficiency anaemia

What are the symptoms of iron deficiency anaemia?

Many people with iron deficiency anaemia will only display a few signs or symptoms of the illness.

The most common symptoms include:

  • tiredness
  • lethargy (lack of energy)
  • shortness of breath (dyspnoea)

Less common symptoms include:

  • headache
  • tinnitus
    - 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
  • hair loss
  • difficulty swallowing (

Changed appearance

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

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

Slow-developing symptoms

The severity of your symptoms can depend on how quickly your anaemia develops. For example, you may notice 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

What causes iron deficiency anaemia?

Iron deficiency anaemia occurs when the body does not have enough iron. A lack of iron can be caused by a number of factors.

Some are outlined below.

Monthly periods

In women of reproductive age, periods are the most common cause of iron deficiency anaemia.

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 your baby has a sufficient blood supply and receives necessary oxygen and nutrients. Many pregnant women require an iron supplement, particularly from the 20th week of pregnancy.

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)

Non-steroidal anti-inflammatory drugs
(NSAIDs) can cause bleeding in the stomach.
are two commonly prescribed NSAIDs.

If your doctor suspects your medication is causing gastrointestinal bleeding, they may be able to prescribe a less harmful medicine as an alternative. Do not stop taking a medicine prescribed for you unless your doctor advises you to.

Stomach ulcers

The acid in your stomach (which usually helps your body to digest food) can sometimes eat into your stomach lining. When this happens, the acid forms an ulcer (an open sore). This is also known as a peptic ulcer.

Stomach ulcers can cause your stomach lining to bleed and this blood loss can lead to anaemia. In some cases the blood loss can cause you to vomit blood or pass blood in your stools (faeces). However, if the ulcer is slow bleeding, you may not have any symptoms.

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).

In diagnosing the cause of your anaemia, your doctor will check for possible signs of cancer. If your doctor suspects 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 treated as quickly as possible.

Read more information about

stomach cancer
bowel cancer


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

Chronic kidney disease

Many people with

chronic kidney disease
(CKD) develop iron deficiency anaemia.

Most people with kidney disease will be given iron supplements through an injection administered intravenously (into a vein). However, daily ferrous sulphate tablets may be tried first.

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
    ulcerative colitis
  • oesophagitis - inflammation of the gullet (oesophagus) caused by stomach acid leaking through it
  • schistosomiasis
    - an infection caused by parasites and 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) - also rare and may be the symptom of another condition


Malabsorption (when your body cannot absorb iron from 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


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

Some studies suggest vegetarians or vegans are more at risk of iron-deficiency anaemia due to the lack of meat in their diet. However, it is possible to gain enough iron in a vegetarian or vegan diet through other types of food such as:

  • beans
  • nuts
  • dried fruit, such as dried apricots
  • wholegrains, such as brown rice
  • fortified breakfast cereals
  • soybean flour
  • most dark-green leafy vegetables, such as watercress and curly kale

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

Read more information about

good sources of iron

How is iron deficiency anaemia diagnosed?

See your doctor if you experience symptoms of iron deficiency anaemia. A blood test will be able to confirm the diagnosis.

Your doctor may also ask questions and carry out a physical examination to find the cause of your anaemia.

Blood test

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

If you have anaemia:

  • your levels of haemoglobin (a protein that transports oxygen) will be lower 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 doctor 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 may have iron deficiency anaemia.

Read more information about

blood tests

Vitamin B12 and folate

If your doctor suspects 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.

Finding the cause

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

  • 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
  • your menstrual pattern - if you are a woman, your doctor may ask if you have been experiencing particularly
    heavy periods
  • your family history - you will be asked whether your immediate family has anaemia or a history of gastrointestinal bleeding or blood disorders
  • blood donation - whether you regularly donate blood or have a history of excessive bleeding
  • other medical conditions - your doctor may ask whether you have recently had another illness or experienced other symptoms, such as weight loss

Physical examination

A physical examination will usually only be necessary if the cause for your iron deficiency anaemia has not been found.

Your doctor 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 you may have are explained below.

Rectal examination


rectal examination
is generally only necessary if there is rectal bleeding. This is a common procedure which can help your doctor determine whether there is something in your gastrointestinal tract that may be causing bleeding. Your doctor will insert a gloved, lubricated finger into your rectum so they can feel for abnormalities.

A rectal examination is not something to be embarrassed about as it is a procedure your doctor will be used to performing. It should not cause significant pain or discomfort and you will only usually feel a slight sensation that your bowels are moving around.

Pelvic examination

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

During a pelvic examination, your doctor 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 doctor inserting gloved, lubricated fingers into your vagina to feel whether your ovaries and uterus (womb) are tender or enlarged.

A pelvic examination will not be carried out without your consent, and you will have the option of having someone with you during the procedure.


Iron deficiency anaemia is common during [pregnancy] so your doctor will only look for an alternative cause if your haemoglobin level is particularly low, or if your symptoms or medical history suggest your anaemia may be caused by something else.


Your doctor 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:

  • an abnormality was detected 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 has a very low haemoglobin level

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.

What is the treatment for iron deficiency anaemia?

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

Iron supplements

Your doctor will prescribe an iron supplement to restore iron missing from your body. The most commonly prescribed supplement is ferrous sulphate, taken orally (by mouth) two or three times a day.

Some people can experience side effects when taking iron supplements including:

  • nausea (feeling sick)
  • sickness
  • abdominal (tummy) pain
  • heartburn
  • constipation
  • diarrhoea
  • black stools (faeces)

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

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

Storing iron supplements

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

Dietary advice

If a lack of iron in your diet is thought to contribute to your iron deficiency anaemia, your doctor will advise on

how to include more iron in your diet

Iron-rich foods include:

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

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

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

  • tea and coffee
  • 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
  • wholegrain cereals - although wholegrains are a good source of iron themselves, they contain phytic acid which can interfere with how your body absorbs iron from other foods and pills

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 detailed, personalised guidance about how you can change your diet.

Underlying causes

Your doctor will also need to ensure the underlying cause of your anaemia is treated so anaemia does not become a recurrent problem.

For example, if

non-steroidal anti-inflammatory drugs
(NSAIDs) are causing bleeding in your stomach, your doctor may prescribe an alternative type of medicine to 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.


Your doctor will ask you to return for a check-up two to four weeks after you have started taking iron supplements to assess how well you have responded to the treatment. Your haemoglobin levels will be checked in a blood test.

If the result of the

blood test
shows an improvement, you will be asked to return in two to four months for a further blood test.

Once your haemoglobin levels and red blood cells are normal, your doctor will usually recommend you continue taking iron supplements for three months to help replenish the iron stores in your body.

After this, depending on the cause of your iron deficiency anaemia, you should be able to stop taking the supplements. Your condition will then be monitored every three months for one year.

Continuing treatment

In some people, after iron stores in the body have been replenished, they start to fall again. This could happen if:

  • you do not eat an iron-rich diet
  • you are pregnant
  • you have heavy periods (menorrhagia)

In these circumstances, you may be prescribed an ongoing iron supplement. This will usually be one tablet a day. This will stop your anaemia returning.

If treatment fails

If your iron levels do not improve, your doctor will ask how regularly you have been taking your iron supplements. Some people are put off taking the medication because of the side effects. However, your conditions will not improve if you do not take the supplements.

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

What are the complications of iron deficiency anaemia?

Iron deficiency anaemia rarely causes serious or long-term complications. However, some people with iron deficiency anaemia find that it affects their daily life.

Some common complications are outlined below.


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 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


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 some women experience after having a baby).

Research suggests 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 iron levels
  • do less well in mental ability tests

Restless legs syndrome (RLS)

Some cases of

restless legs syndrome
(RLS) are thought to be caused by iron deficiency anaemia. Doctors may refer to this as secondary RLS.

Restless legs syndrome (RLS) is a common condition affecting the nervous system, which causes an overwhelming, irresistible urge to move the legs. It also causes an unpleasant feeling in the feet, calves and thighs.

RLS caused by iron-deficiency anaemia is usually treated with iron supplements.

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.