Iron deficiency anaemia is when a lack of iron in the body means that the blood does not produce enough haemoglobin — the iron-based pigment in red blood cells that gives them their colour and carries oxygen.
Not all people who are low in iron have iron deficiency anaemia – severe and prolonged iron deficiency is needed to cause anaemia.
Iron deficiency anaemia, one of several types of anaemia, is common in Australia, particularly in women, premature or very small babies, children and people on restricted diets. Iron deficiency anaemia is usually easy to treat.
Symptoms of iron deficiency anaemia
The symptoms of iron deficiency anaemia are caused by a lack of oxygen being supplied to the tissues.
You may feel:
- short of breath (especially when exercising);
- light-headed or dizzy; or
- have headaches or become irritable.
In addition, your skin and the inside of your mouth may be pale.
Older people with anaemia may get angina (pain in the chest) because the heart has to work harder to supply enough oxygen to the body.
Signs and symptoms of iron deficiency include the following.
- In the early stages of iron deficiency you may have no symptoms or just mild fatigue.
- You may be more likely to pick up infections.
- Eventually, your nails can become spoon-shaped and brittle, the corners of your mouth may crack, and you may have difficulty swallowing.
- Some people with low iron levels, especially children, may have difficulty with concentration and memory, or have trouble learning. Iron deficiency anaemia in children may cause problems with development.
- Some people get cravings for unusual substances, such as ice or earth (soil).
Causes of iron deficiency anaemia
Iron is stored in your liver, spleen and bone marrow and is vital for mental and physical well-being.
While most of the body’s iron is recycled from red blood cells that have died, a small but essential amount comes from food. (Iron is one of the many minerals found in food.)
If your body does not have enough iron, it can’t make enough haemoglobin.
The reasons for getting iron deficiency anaemia include the following.
Loss of iron as a result of blood loss, for example from:
- heavy periods;
- stomach and bowel problems (including ulcers, bowel polyps, haemorrhoids or cancer), which can go unnoticed because the blood loss may be very slow; or
- regular use of medicines that can cause stomach bleeding (for example, aspirin and non-steroidal anti-inflammatory medicines – NSAIDs).
Inadequate intake of iron in the diet to meet the demands of the body, due to:
- lack of iron in the diet over a long period of time (vegetarians and vegans are at increased risk);
- fast growth in children;
- being born early (premature);
- being pregnant — the mother’s iron stores go to her baby; or
- excessive exercise — where the body needs more iron than usual and iron is also lost in sweat.
Inadequate absorption of iron from the gut, due to:
- being unable to absorb iron in the bowel, for example in Crohn’s disease or untreated coeliac disease; or
- surgery that involves removing or bypassing part of the stomach or small bowel (for example, some types of weight loss surgery).
How is iron deficiency anaemia diagnosed?
Your doctor will ask about your symptoms and perform a physical examination, looking for signs of anaemia and iron deficiency.
If they suspect iron deficiency anaemia, they may also ask about your diet and other possible causes.
If your anaemia is not severe you may not have any symptoms and may be diagnosed following a routine blood test.
Your doctor will recommend blood tests to determine whether you have iron deficiency anaemia, and possibly further tests to work out the cause.
- A full blood count and blood film show the haemoglobin level, plus the number and size of red blood cells. A low haemoglobin plus red blood cells that are smaller than normal and pale in colour are features of iron-deficiency anaemia.
- Iron studies (including iron, ferritin and transferrin) measure iron and iron stores in the body.
Other tests may be needed to see if there is any bleeding in your stomach or bowel, or a condition which may be affecting the absorption of iron.
Your doctor may refer you to a gastroenterologist (a specialist in conditions affecting the digestive tract) or surgeon, who may recommend an endoscopy and/or colonoscopy to investigate your digestive tract.
Further investigation of women with heavy periods may involve an ultrasound of the pelvis to determine if there is an underlying cause, such as fibroids in the uterus (womb).
Treatment for iron deficiency anaemia
Treatment for iron deficiency anaemia involves treating the underlying cause of your anaemia and replacing iron with iron supplements and a good diet.
Your blood count will be checked regularly to make sure the anaemia has not returned.
Iron supplements are usually given as tablets, but if you need a high dose of iron, you may have an injection or intravenous infusion (via a drip into a vein).
Side effects of Iron tablets can include:
- dark or black bowel motions (this is harmless);
- diarrhoea; or
If side effects are troubling you, your doctor may change the tablets or suggest taking a smaller dose more frequently.
Take your tablets as prescribed and keep tablets out of the reach of children (an accidental overdose of iron tablets can be dangerous for children).
Taking your iron supplements
- Take iron tablets on an empty stomach (at least an hour before eating) to increase absorption. However, if you get bad indigestion you should take them with food.
- Don’t take iron supplements with milk, tea or coffee — these can reduce the amount of iron your body absorbs.
- Vitamin C helps with iron absorption – your doctor may recommend taking your tablets with orange juice.
- Wait 2 hours after taking iron tablets before taking other medicines. Some medicines and supplements – including antacids, medicines for gastro-oesophageal reflux disease (GORD) and calcium supplements – can reduce iron absorption.
- Keep taking the tablets for at least 3 months or until your doctor tells you to stop. You should take them until well after your haemoglobin is normal.
If you are pregnant you may be given iron tablets. A healthy diet is also recommended.
Children with iron deficiency anaemia should be given their iron medicine (usually in liquid form) before meals with orange juice (not milk), as vitamin C increases iron absorption. They should use a straw because liquid iron can discolour the mouth.
Your body absorbs only a small amount of iron, so it is important to eat a lot of iron-rich foods (meat, fish or poultry, whole or enriched grains) every day. If you don’t eat meat (the best source of iron), make sure you eat plenty of leafy green vegetables, iron fortified foods (such as cereals), eggs, nuts, wholemeal bread and pasta, dried fruit, beans and lentils.
Eating a lot of foods rich in vitamin C (e.g. citrus fruits, kiwi fruit, red capsicum, leafy green vegetables) will help iron absorption.
Limit your milk intake to 500 mL daily in adults. Talk with your doctor, dietitian or community health nurse about other ways to get enough calcium.
Don’t drink tea with meals — it prevents iron absorption.
Your doctor or dietitian can tell you how much iron you need daily. A dietitian can plan a diet for you, and discuss iron intake for vegetarians.
For severe iron deficiency anaemia, you may need a blood transfusion.
If you have heavy periods your doctor may be able to suggest medicines (such as the oral contraceptive pill) to reduce blood loss.
The best way to prevent iron deficiency is to ensure your intake of iron is adequate, especially if you are at increased risk. See your doctor or a dietitian for advice on following an iron-rich diet.
Iron supplements may be recommended to prevent iron-deficiency anaemia in people who are unable to get sufficient iron from food.