What is the most common cause of anaemia?

Iron deficiency is the most common cause worldwide. It can result from insufficient dietary iron, poor absorption, increased needs (such as pregnancy), or blood loss — including heavy periods and slow bleeding from the gut. Because iron deficiency in adults can be the first sign of gastrointestinal bleeding, doctors look for the underlying cause rather than simply prescribing iron. Other causes include B12 or folate deficiency, chronic disease, kidney problems, and inherited conditions.

Why does my doctor need to find the cause of my anaemia?

Anaemia is a sign, not a diagnosis, so treating the low haemoglobin without identifying why it happened can hide a serious underlying problem. For example, iron deficiency in an adult may be caused by slow bleeding in the digestive tract that itself needs investigation and treatment. Finding the cause ensures you get the right treatment and that nothing important is missed, which is why your history, blood tests, and sometimes further investigations matter.

What should I bring to an anaemia appointment?

Bring a record of your symptoms (tiredness, breathlessness, dizziness, palpitations), your diet (especially if vegetarian or vegan), and any sources of blood loss such as heavy periods or blood in the stool. Crucially, bring previous blood results — haemoglobin, ferritin, iron studies, B12, and folate — and a full list of medications and supplements, including anti-inflammatories and blood thinners that can cause gut bleeding. This helps your doctor work out the type and cause quickly.

Can diet alone fix anaemia?

It depends on the cause and severity. Mild iron or vitamin deficiency from diet can often be improved with dietary changes and, if needed, supplements. However, if the anaemia is due to blood loss, absorption problems, or another underlying condition, diet alone will not resolve it, and the cause must be treated. Never start high-dose supplements without medical advice, as the right treatment depends on the specific type of anaemia confirmed by blood tests.

Preparing for Appointments with Anaemia

Quick answer: Track your symptoms (tiredness, breathlessness, dizziness, pale skin) and bring any previous blood results, especially your haemoglobin, ferritin, and B12/folate. Anaemia is not a diagnosis in itself — it is a sign, and the key is finding the cause. Note your diet, periods (if relevant), any bleeding, and your full medication and supplement list.

Anaemia means your blood carries less oxygen than it should, usually because of low haemoglobin. But the number is only the start — the whole point of the appointment is to find why, because the cause (iron deficiency, B12/folate, blood loss, chronic disease) determines the treatment.

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What to Track Before Your Appointment

Symptoms: fatigue, breathlessness on exertion, dizziness, palpitations, pale skin, headaches
Diet: red meat, leafy greens, and whether you are vegetarian/vegan
Blood loss: heavy periods, blood in stool, recent surgery or donation
Previous results: haemoglobin, ferritin, iron studies, B12, folate. A appointment notebook keeps them together.
Medications: including anti-inflammatories and blood thinners, which can cause gut bleeding

Common Types of Anaemia

Type	Clue
Iron deficiency	Low ferritin; often heavy periods, diet, or gut blood loss
B12 / folate deficiency	Large red cells; diet, absorption, or pernicious anaemia
Anaemia of chronic disease	Ongoing inflammation or chronic illness
Other	Kidney disease, thyroid, bone marrow or inherited causes

Helpful for this appointment

iron supplement — for confirmed iron deficiency (confirm dose with your doctor)
appointment notebook — to track symptoms and blood results across visits

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Why Finding the Cause Matters

Treating anaemia without finding the cause can mask a serious underlying problem — for example, iron deficiency in an adult can be the first sign of slow gut bleeding that needs investigation. So expect your doctor to look for the source, not just prescribe iron.

Questions to Ask

What type of anaemia do I have, and what is causing it?
Do I need further tests to find the source (for example, of bleeding)?
What treatment do I need, and for how long?
Should I change my diet or take a supplement — and which?
When should my blood be rechecked?

Regional Notes

Singapore: Investigated by GPs and, if needed, haematologists or gastroenterologists; full blood count and iron studies are standard and inexpensive.

Australia: GP-led work-up with iron studies and B12/folate, bulk-billed or low-cost; referral for endoscopy if gut blood loss is suspected.

United States: Primary care work-up with CBC and iron studies; gastroenterology referral for unexplained iron deficiency.

KEY SOURCES

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Medical Disclaimer: This guide is for informational and preparation purposes only. It does not constitute medical advice, diagnosis, or treatment. Always consult a qualified medical professional for guidance specific to your situation.