Quick answer. Anaemia means you have too little haemoglobin (or too few healthy red blood cells), so your blood carries less oxygen around the body – which is why it often causes tiredness, breathlessness and pallor. Anaemia is not a diagnosis in itself but a sign that something else is going on, so the key is always to find and treat the underlying cause rather than simply taking iron. Causes range from common and easily treated (iron or vitamin deficiency, heavy periods) to ones that need proper investigation (slow gut bleeding, inherited conditions, bone-marrow problems). A simple blood test – the full blood count – is the starting point.
Trying to make sense of a blood disorder or abnormal results?
Message our care team on WhatsApp. Tell us what’s going on and we’ll help you find the right haematologist — free, with no obligation.
Chat with our care team on WhatsAppNot sure who to see? Find the right specialist →
In a medical emergency, or for severe or sudden symptoms such as breathing difficulty, chest pain, fainting or stroke signs, call 995 immediately.
The single most important idea: anaemia is a clue, not the whole story. “Just take iron” can hide the real reason your blood count is low, so the goal is to work out why.
What anaemia is
Anaemia is a condition in which there are too few healthy red blood cells, or too little haemoglobin, to carry enough oxygen around the body. Red blood cells contain haemoglobin, the iron-rich protein that binds oxygen in the lungs and releases it to your organs and muscles. When there is either too little haemoglobin or too few healthy red cells, tissues receive less oxygen, and the body works harder to compensate – which explains the classic symptoms.
Anaemia is common, and it is best thought of as a sign rather than a single disease. Many different problems can lead to it, and they are treated in completely different ways, so the most useful part of managing anaemia is finding out what is causing it. It ranges from mild and almost symptomless, picked up by chance on a blood test, to severe and clearly unwell. The measure that matters is the haemoglobin level, always interpreted by a doctor alongside your history and other results.
Symptoms to recognise
Because every tissue depends on oxygen, the symptoms are wide-ranging and often vague. Common features include:
- Persistent tiredness and a lack of energy;
- Pale skin, and sometimes pale lips, gums or the inside of the lower eyelids;
- Breathlessness on exertion, such as climbing stairs;
- Light-headedness or dizziness, and headaches;
- A fast or pounding heartbeat (palpitations);
- Cold hands and feet, and reduced concentration.
Symptoms usually come on gradually and can easily be mistaken for stress, ageing or poor sleep, so many people only discover the problem through a routine blood test. Mild anaemia may cause few or no symptoms at all. Some causes add their own clues – for example a sore or smooth tongue and cracks at the corners of the mouth can point to iron or vitamin deficiency, while a yellow tinge to the skin or dark urine can suggest that red cells are being broken down too quickly. In more severe cases, chest pain and marked breathlessness can occur, and these need prompt medical care.
The main causes, grouped simply
It helps to group the causes into a few plain-English buckets:
- Not enough of the building blocks – the body needs iron, vitamin B12 and folate to make red cells. Iron deficiency is the commonest cause of all, arising from blood loss (such as heavy periods or slow gut bleeding), poor intake, or poor absorption. A shortage of vitamin B12 or folate is another important and treatable cause.
- Blood loss – losing red cells faster than they can be replaced, from heavy menstrual periods, or from slow gastrointestinal bleeding (ulcers, polyps, piles, and rarely stomach or bowel cancer).
- Red cells being destroyed too fast (haemolysis) – the body breaks down red cells faster than it makes them. This includes inherited conditions such as thalassaemia and G6PD deficiency, both relevant in Singapore.
- The bone marrow not making enough – production falls because of chronic disease, kidney disease (which reduces the hormone that drives red-cell production), or marrow problems such as leukaemia.
- Anaemia of long-term illness – ongoing infection, inflammation or chronic conditions can quietly suppress red-cell production even when the diet is adequate.
Why the cause matters
Finding the cause is not a formality – it changes everything, because the treatments are completely different and can even work in opposite directions. Iron replacement is right for iron deficiency, but it is not the answer for thalassaemia trait, where the body already handles iron differently and unnecessary iron can build up and cause harm. Similarly, anaemia from B12 or folate deficiency will not improve with iron, and anaemia that is really a sign of slow internal bleeding needs the source of bleeding found and treated, not just the blood count topped up. This is why anaemia should be investigated, not treated blindly with iron. Taking iron supplements on your own can cause iron overload, mask the real problem, and delay a diagnosis that matters.
Who is at higher risk
Anaemia can affect anyone, but some groups are more prone to it: women with heavy periods; women who are pregnant, when the demand for iron and folate rises; older adults, who more often have chronic illness or a hidden source of bleeding; people with a poor diet or certain restrictive diets that are low in iron, B12 or folate; those with chronic illnesses such as kidney disease, inflammatory conditions or long-term infection; and people with inherited red-cell disorders such as thalassaemia, which is a common trait in Singapore and the surrounding region.
How anaemia is diagnosed
The starting point is a full blood count (FBC), which confirms anaemia and reports the average size of the red cells. Small red cells tend to point towards iron deficiency or thalassaemia, while large red cells point towards B12 or folate deficiency – a useful signpost that helps direct the next steps. A blood film, examined under the microscope, adds further clues to the shape and appearance of the cells.
From there the doctor targets the likely cause with further tests – iron stores (ferritin), vitamin B12 and folate levels, kidney and inflammatory markers, and sometimes haemoglobin studies or bone-marrow tests. Just as important is looking for a source of the problem: for example, checking the gut for hidden bleeding, or reviewing periods, diet, medicines and other illnesses. In Singapore, iron deficiency is the commonest cause, and thalassaemia trait is a common local finding, so the two are often considered side by side when the red cells are small.
Treatment: treat the cause
Treatment is tailored to the underlying cause rather than being one-size-fits-all. That may mean iron replacement for iron deficiency (together with finding out why the iron ran low), B12 or folate replacement with dietary advice, treating and controlling a chronic disease, or specialist treatment for inherited or bone-marrow causes. Where the problem is blood loss, stopping the bleeding – for instance managing heavy periods or a gut source – is central. For severe anaemia, or when someone is very unwell, a blood transfusion may be needed to restore oxygen-carrying capacity quickly. Because the right treatment depends entirely on the diagnosis, taking iron without knowing the cause can be harmful and can hide a serious problem.
Self-care and diet
A balanced diet supports healthy blood, and where relevant a doctor may suggest iron-rich foods such as lean red meat, poultry, fish, beans, lentils, tofu and dark green leafy vegetables, along with foods containing vitamin B12 and folate. Vitamin C-rich foods eaten with plant sources of iron can help absorption. However, diet and supplements are not always the answer – they will not correct anaemia caused by ongoing bleeding, an inherited condition or a marrow problem, and unsupervised supplements can do harm. The safest approach is to treat any anaemia under a doctor’s guidance, follow the advice given for your specific cause, and keep up with any monitoring or follow-up blood tests.
When to see a doctor – and red flags
See a doctor to investigate anaemia rather than self-treating with iron. Book an appointment for ongoing tiredness, breathlessness, pallor or palpitations, or if a blood test shows anaemia, so the cause can be found. Anaemia appearing in a man or a post-menopausal woman especially warrants checking the gut for a hidden source of bleeding. Also see a doctor promptly for blood in the stool, black tarry stools, blood in the urine, unexplained weight loss, or a change in bowel habit.
Seek urgent care for severe breathlessness or chest pain, fainting, black or bloody stools or vomiting blood, or if you simply feel very unwell. Call 995 or go to A&E for chest pain or severe breathlessness. A GP can start the work-up and arrange the first tests; a haematologist helps with complex, severe or unexplained cases. HealthHub is a useful source of general health information for people in Singapore.
Related blood & haematology topics
- Iron-deficiency anaemia
- Vitamin B12 & folate deficiency
- Thalassaemia
- G6PD deficiency
- Deep vein thrombosis (DVT)
- Low platelets (thrombocytopenia)
- Haemophilia
- Multiple myeloma
- Understanding your full blood count
- Pulmonary embolism
- Haematologists in Singapore
Sources
- SingHealth — Anaemia: causes, symptoms, diagnosis and treatment; local prevalence and thalassaemia-gene carriers.
- HealthXchange (SingHealth / SGH) — iron deficiency as the commonest local cause; warning against unsupervised iron and overload risk.
- HealthHub (Singapore) — general patient information on anaemia and healthy diet.
- NHS — Iron-deficiency anaemia and anaemia symptoms and diagnosis (corroboration).
- NHLBI — Anemia: mechanisms and types (general reference).