In short: Microcytic anaemia means your red blood cells are smaller than normal — most often because of iron deficiency. It is common, easily picked up with a blood test, and usually very treatable once the cause is found.
What Is Microcytic Anaemia?
Anaemia means your blood does not have enough healthy red blood cells, or enough of the protein inside them called haemoglobin. Haemoglobin carries oxygen around your body. When levels are low, your organs and muscles receive less oxygen, which can leave you feeling tired and unwell.
Doctors describe anaemia by the size of the red blood cells. "Microcytic" simply means the red blood cells are smaller than normal. Your size measure on a blood test is the mean cell volume (MCV), and in microcytic anaemia the MCV is low.
By far the most common cause of microcytic anaemia is iron deficiency. Iron is an essential building block of haemoglobin, so when iron runs low, the body makes fewer and smaller red blood cells.
How Common Is It?
Iron deficiency is the most common nutritional deficiency in Australia and around the world, and iron deficiency is the leading cause of anaemia. It is especially common in women of reproductive age, young children, and during pregnancy.
Symptoms to Look Out For
Iron deficiency can develop slowly, and mild cases may cause few or no symptoms. As iron stores fall further, you may notice:
- Tiredness, low energy, or feeling weak
- Shortness of breath, especially with activity
- Pale skin
- Dizziness or light-headedness
- Headaches
- Poor concentration or "brain fog"
- Cold hands and feet
- A fast or pounding heartbeat
- Brittle nails or increased hair shedding
- Restless legs, particularly at night
- Unusual cravings to chew ice or non-food items (known as pica)
These symptoms can have many causes, so they do not always mean you have anaemia. A simple blood test is the only way to know for sure.
When to Seek Care Sooner
Make an appointment promptly, or seek urgent care, if you experience chest pain, severe breathlessness, fainting, or notice blood in your bowel motions or vomit. Very heavy or prolonged menstrual bleeding is also worth discussing with your GP.
What Causes Iron Deficiency?
Iron deficiency develops when the body loses more iron than it takes in, or cannot absorb enough. Common reasons include:
Not Enough Iron in the Diet
Iron comes from food, and some eating patterns provide less of the readily absorbed form. Vegetarians, vegans, and people who eat little red meat can be more prone to low iron if their diet is not well planned.
Increased Need for Iron
The body needs more iron during periods of growth and change, including infancy, childhood, the teenage years, and pregnancy. Towards the end of pregnancy in particular, iron requirements rise significantly.
Blood Loss
Because blood contains iron, ongoing blood loss is a frequent cause. This includes heavy menstrual periods, and in some people, slow bleeding from the stomach or bowel. Frequent blood donation can also contribute.
Problems Absorbing Iron
Some conditions reduce how well the gut absorbs iron, such as coeliac disease or other digestive disorders, and some medicines.
It is worth knowing that not all microcytic anaemia is caused by iron deficiency. Inherited conditions that affect haemoglobin, such as thalassaemia, also produce small red blood cells. This is one reason it is important to have low iron properly investigated rather than self-treating.
Who Is Most at Risk?
According to Australian health authorities, the groups at higher risk of iron deficiency include:
- Babies and young children
- Teenage girls
- Women who have heavy menstrual periods
- People who are pregnant or have recently given birth
- Vegetarians and vegans
- Endurance athletes
- Regular blood donors
- People with chronic illnesses or digestive conditions such as coeliac disease
How Is It Diagnosed?
Microcytic anaemia is diagnosed with a simple blood test. Your GP may order:
- A full blood count (FBC) — measures haemoglobin and the size of your red blood cells (MCV)
- Iron studies, including ferritin — ferritin reflects the amount of iron stored in your body and is one of the most useful tests for spotting iron deficiency early
Depending on your age, symptoms, and results, your GP may suggest further tests to find the underlying cause. For example, iron deficiency in men, or in women after menopause, generally needs investigation of the digestive system, because a hidden source of bleeding should be ruled out. Your doctor will explain what is appropriate for your situation.
You can have these tests done conveniently — learn more about pathology and blood tests at our clinic.
Treatment Options
Treatment has two parts: correcting the low iron, and addressing the cause. The right approach depends on how low your iron is and why.
Iron-Rich Foods
Improving dietary iron is an important foundation. There are two types of iron in food:
- Haem iron, found in animal foods such as red meat, lamb, kangaroo, chicken, fish, and eggs. This form is absorbed more easily.
- Non-haem iron, found in plant foods such as legumes (lentils, chickpeas, beans), tofu, wholegrains, leafy green vegetables, nuts, and iron-fortified breakfast cereals.
A few simple habits can help your body absorb non-haem iron:
- Pair plant sources of iron with vitamin C, such as citrus, capsicum, tomato, or kiwifruit
- Eating a small amount of meat, fish, or poultry alongside plant foods can boost absorption
- Tea, coffee, and large amounts of calcium can reduce iron absorption, so it can help to keep these separate from iron-rich meals
Iron Supplements
If diet alone is not enough, your GP may recommend an oral iron supplement. It is best to take iron only when advised by your doctor, at the dose they recommend, because too much iron can be harmful and some people store iron abnormally. Iron tablets can take several months to rebuild your body's stores, so ongoing follow-up blood tests are usual.
Iron Infusion
In some situations — for example, when iron tablets are not tolerated, are not absorbed well, or when iron needs to be replaced more quickly — a doctor may recommend an iron infusion, where iron is given directly into a vein. Whether this is suitable is a clinical decision your GP makes with you, based on your individual circumstances and test results. You can read more about our iron infusion service.
Can Iron Deficiency Be Prevented?
For many people, a balanced diet that includes iron-rich foods is enough to maintain healthy iron levels. Those in higher-risk groups — such as during pregnancy or for people with heavy periods — may benefit from regular check-ins with their GP and, where appropriate, monitoring of their iron levels. Your doctor can advise what is right for you.
How Reliance Medical Centre Can Help
Our GPs at Reliance Medical Centre in Truganina can help you investigate tiredness and other symptoms, arrange the right blood tests, identify the underlying cause, and work with you on a management plan suited to your needs. We provide:
- General practice consultations to assess your symptoms
- On-site pathology referrals for blood tests
- Iron infusions where clinically appropriate
- Ongoing review and follow-up
To discuss your health, book an appointment online or call us on (03) 9958 6699.
Frequently Asked Questions
What is the most common cause of microcytic anaemia?
Iron deficiency is by far the most common cause of microcytic anaemia, where the red blood cells are smaller than normal. Iron is needed to make haemoglobin, so when iron is low the body makes fewer and smaller red blood cells. Less commonly, inherited conditions such as thalassaemia can also cause small red blood cells.
What are the symptoms of iron deficiency anaemia?
Common symptoms include tiredness, weakness, shortness of breath, pale skin, dizziness, headaches, poor concentration, cold hands and feet, brittle nails, and restless legs. Some people also have unusual cravings to chew ice. Mild iron deficiency may cause no symptoms at all, so a blood test is the only way to know for sure.
How is microcytic anaemia diagnosed?
It is diagnosed with a simple blood test. A full blood count (FBC) measures your haemoglobin and the size of your red blood cells, and iron studies — especially ferritin — show how much iron is stored in your body. Your GP may suggest further tests to find the underlying cause.
What foods are high in iron?
Haem iron, which is absorbed more easily, is found in red meat, lamb, kangaroo, chicken, fish and eggs. Non-haem iron is found in legumes, tofu, wholegrains, leafy green vegetables, nuts and iron-fortified cereals. Pairing plant sources of iron with vitamin C, such as citrus or tomato, helps your body absorb more.
Should I take iron supplements for iron deficiency?
Only take iron supplements when advised by your doctor, at the dose they recommend. Too much iron can be harmful, and some people store iron abnormally. Iron tablets can take several months to rebuild your stores, so follow-up blood tests are usual.
When should I see a doctor about iron deficiency?
See your GP if you have ongoing tiredness, breathlessness or other symptoms of anaemia, or very heavy periods. Seek urgent care for chest pain, severe breathlessness, fainting, or blood in your bowel motions or vomit. Iron deficiency in men and in women after menopause should always be investigated.
Trusted Sources for Further Reading
- Healthdirect Australia — Iron deficiency and Anaemia
- Better Health Channel (Victorian Government) — Iron and iron deficiency
- Eat For Health (NHMRC) — Iron
This article is for general information only and does not replace professional medical advice. Iron levels and the right treatment differ from person to person. Please do not start iron supplements without guidance, as too much iron can be harmful. If you have concerns about your health, please consult your GP.
