Iron deficiency anaemia

Written by Ellen Lees
Ellen Lees
Nutritionist Resource Content Team

Last updated 3rd April 2024 | Next update due 3rd April 2027

Iron deficiency anaemia is caused by a lack of iron in the bloodstream, which leads to your body not being able to create enough healthy red blood cells to transport oxygen around your body. The body then becomes starved of oxygen, making the sufferer feel tired and drained of energy.

On this page, we will look at what iron deficiency anaemia is, its symptoms, causes, diagnosis and how a nutritionist can help with the condition.

What is iron deficiency anaemia?

Iron deficiency anaemia is a type of anaemia that can make you feel tired, experience spells of breathlessness and in some cases can cause heart palpitations.

You can develop this condition if you do not have enough iron in your body. You need iron for many important processes, especially for creating haemoglobin, which is a protein that carries oxygen through your bloodstream.

Your small bowel absorbs iron from the things you eat and drink. It’s then carried to your bone marrow through your bloodstream to create new red blood cells. In the bone marrow, the iron is combined with other proteins to create haemoglobin.

So, if you do not have enough iron in your body, you won’t be able to make enough haemoglobin that your body needs to create new, healthy red blood cells. This then leads to the symptoms of iron deficiency anaemia such as tiredness and lack of energy, which we have detailed below.

Symptoms of iron deficiency anaemia

According to the NHS, many who have iron deficiency anaemia will only show a few signs or symptoms.

The severity of the symptoms often depends on how fast the anaemia develops. You might only notice one or two symptoms at first, or they might gradually develop over time if your anaemia is caused by a long-term problem such as a stomach ulcer.

The most common symptoms of iron deficiency anaemia include:

  • tiredness
  • lack of energy
  • a pale complexion
  • heart palpitations
  • bouts of breathlessness, particularly on exertion.

Some less common symptoms include:

  • altered taste
  • headaches
  • itching
  • hair loss
  • a sore tongue
  • difficulty in swallowing (dysphagia)
  • sore ulcers on the corners of your mouth.

There is a possibility that these symptoms are caused by something other than iron deficiency anaemia. If you are experiencing any of these symptoms, you should visit your GP for advice.

Causes of iron deficiency anaemia

A lack of iron can be caused by a number of factors. Below we list some of the most common causes of iron deficiency anaemia:


It’s common for pregnant people to develop this condition. When you are pregnant, your body needs extra iron to make sure your baby has an ample blood supply and enough nutrients and oxygen. Some pregnant women simply need to increase their intake of iron-rich foods, and others might need to take iron supplements.

Monthly periods

For women who are of reproductive age, periods are one of the most common causes of iron deficiency anaemia. Typically, only people who have heavy periods develop this condition due to the amount of blood lost.

Gastrointestinal blood loss

The gastrointestinal tract is responsible for digesting your food. It contains your intestines and stomach.

Bleeding in the gastrointestinal tract is the most common cause of iron deficiency anaemia in men, and also in women who have been through menopause. The majority of people don’t tend to notice they have it as blood isn’t typically present in their stools and their bowel habits don’t tend to change.

Some additional causes of gastrointestinal bleeding are as follows:

  • Stomach ulcers - Stomach acid can occasionally eat into the lining of your stomach and form a stomach ulcer. These ulcers may cause your stomach lining to bleed, which can lead to anaemia.
  • Non-steroidal anti-inflammatory drugs (NSAIDs) - NSAIDs such as aspirin and ibuprofen can cause bleeding in the stomach. If your GP believes that this medicine is causing stomach bleeding, they can suggest an alternative prescription.
  • Gastrointestinal cancer - Even though it is rare, gastrointestinal bleeding can be caused by cancer of the colon or stomach. Your GP will check for signs of cancer when diagnosing anaemia.

Chronic kidney disease

If you have chronic kidney disease you are more likely to develop iron deficiency anaemia. In this case, you may be given iron supplement injections to help boost your iron intake.

Other less common causes

  • nosebleeds
  • donating blood
  • oesophagitis (inflammation of the gullet)
  • inflammatory bowel disease
  • serious trauma
  • haematuria (blood in your urine)
  • schistosomiasis (an infection caused by parasites)


Malabsorption is a term that describes the point when your body is unable to absorb iron from your food. This can happen after you have surgery to remove your stomach or if you have coeliac disease.

Lack of an iron-rich diet

If you have a lack of iron-rich foods in your diet, it can make you more likely to develop iron deficiency anaemia, but it’s rarely the main cause unless you are pregnant. Typically, it will be combined with one of the other causes mentioned above.

There are two key sources of iron in food - haem iron (from animal sources) and non-haem iron (from plant-based sources). These two types of iron are absorbed into your body with different efficiency.

  • Haem iron - This typically originates from myoglobin and haemoglobin in sources of protein from animals. It’s also easily absorbed into your body, as the majority of inhibitory factors in the diet do not influence it.
  • Non-haem iron - This type of iron is usually found in dark green leafy vegetables, beans, fortified cereals and pasta. Some forms of non-haem iron such as hemosiderin and ferritin take longer to absorb into the body compared to most haem sources.

Some research suggests that vegans, vegetarians and others who have a lack of meat in their diet are prone to developing the condition, so it is especially important to obtain iron from other, non-haem sources. Having said this, those who do eat meat can also develop iron deficiency anaemia, so increasing your intake of foods that contain haem iron is advised if you are experiencing symptoms.


If you think you might have iron deficiency anaemia, visit your GP. They will be able to confirm if you have the condition with a simple blood test. They may also ask a number of questions and conduct a physical examination to determine the cause of it.

Blood test

For diagnosis, a blood sample will be taken from a vein in your arm. All the types of blood cells will be measured in this sample.

If you have anaemia you will have:

  • a low level of haemoglobin
  • fewer red blood cells than usual
  • paler and smaller red blood cells than normal.

You might also be tested for ferritin, a protein that stores iron. You may have iron deficiency anaemia if your ferritin levels are low.

Discovering the cause

You might be asked a number of questions about your medical history and lifestyle such as:

  • If you donate blood and how often.
  • If you have a history of anaemia in your family.
  • What your diet consists of (i.e. if you eat enough iron-rich foods).
  • If you are a female, you might be asked if you have been experiencing particularly heavy periods.
  • If you take any medication that may cause gastrointestinal bleeding.
  • If you have experienced any other medical conditions or symptoms, such as dramatic weight loss.

Physical examination

Your GP will only conduct a physical examination if they do not find the cause through your symptoms and medical history. They might examine your abdomen for gastrointestinal bleeding or look for signs of heart failure.

Two specific types of physical examination include:

  • Rectal examination - This will only be needed if you are losing blood from your bottom. This procedure is fairly common and can help find out if you have something in your gastrointestinal tract that may be causing the bleeding.
  • Pelvic examination - Women may have a pelvic exam if heavy menstrual bleeding is suspected to be a major cause of the anaemia.

GP referrals

Your GP may refer you to a specialist if they cannot identify the cause. For example, if you are a woman experiencing heavy menstruation, you might be referred to a gynaecologist.


To combat iron deficiency anaemia your doctor will most likely prescribe iron supplements for you to take and/or a diet change to include more iron-rich foods.

Iron supplements

The length of your treatment will depend on the severity of the anaemia and your doctor will be able to advise you on which supplement is suitable for your situation. After a couple of weeks, a blood test will be able to determine if the supplements are working. If you are taking tablets, drinking orange juice to wash them down can be helpful as it contains plenty of vitamin C, a vitamin that increases your body’s ability to absorb iron.

When the level of iron in your blood is back to normal, you should still take the supplements for a minimum of three more months to make sure you do not become anaemic again.

Some people may experience side effects when taking iron supplements. You might experience some nausea, constipation, an upset stomach or diarrhoea. If these side effects become a problem, you should consult your GP immediately.

If the side effects are causing you problems, you might be advised to try:

  • Taking a lower dose of medicine. If you do this, the course will need to be lengthened to fully treat the anaemia.
  • Consuming your supplements with meals. The food will reduce your body’s absorption of iron which means you will have to lengthen the course of the treatment.
  • Drinking an increased amount of fluids to combat constipation.

Iron supplements may make your stools black. This is common so there should be nothing to worry about. But in some cases, it can be confused with blood in the stools, which comes from internal bleeding that will need to be assessed.

Remember to store your iron supplements in a place away from children. If a child overdoses on iron supplements it can be very dangerous.

An iron-rich diet

A lack of iron-rich foods in your diet is believed to contribute to the development of iron deficiency anaemia. A GP or nutritionist will be able to recommend what foods to add to your diet to increase your iron intake. If you do consult a nutritionist, they will be able to create an in-depth diet plan suited to you, to ensure that the additions to your diet are sustainable for the duration of the treatment.

Here are a number of examples of iron-rich foods:

  • fortified bread or cereals
  • eggs
  • fish
  • dark green, leafy vegetables
  • brown rice
  • tofu
  • dried fruit
  • meat
  • beans
  • seeds
  • nuts
  • others include mango chutney, dark chocolate, pastry, gingernut biscuits, cocoa powder and curry powder.

You should also consider a balanced diet that contains foods from all major food groups. This diet should include plenty of vitamin C to help your body absorb iron more easily.

In some cases, high levels of certain foods and drinks can inhibit the absorption of iron.

These include:

  • dairy products
  • coffee
  • tea
  • whole grain cereals – these contain phytic acid that may stop your body from absorbing iron from other supplements even though they are a good source of iron themselves.

How can a nutritionist help with iron deficiency anaemia?

It can be very draining if you are feeling tired and lethargic on a daily basis. So to prevent and treat iron deficiency anaemia it’s advised to eat a balanced diet that contains a number of iron-rich foods. A nutritionist will be able to give you a personalised meal plan with all the nutrients needed to improve your quality of life. This will help alleviate the pressure of finding food to create healthy and iron-rich meals. You can use Nutritionist Resource's search tool to find a qualified professional best suited to you.

Before making any radical changes to your diet please consult your GP.

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