Quick answer. Anaemia means your body lacks enough healthy red blood cells, and iron-deficiency anaemia is the most common type in Singapore. Typical symptoms are tiredness, weakness, pallor, breathlessness on exertion, dizziness and a fast heartbeat. Common causes include low dietary iron (more likely in vegetarians/vegans), heavy menstrual periods, and bleeding in the gut. A doctor diagnoses it with a full blood count (FBC) and ferritin test. Treatment is iron tablets plus an iron-rich diet, but the most important step is finding WHY you are iron-deficient. In men and post-menopausal women, unexplained iron-deficiency anaemia can be a warning sign of bowel cancer and must be investigated.
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Iron-deficiency anaemia is one of the most common nutritional problems seen by GPs in Singapore. It develops when your body does not have enough iron to make haemoglobin, the protein in red blood cells that carries oxygen. The result is often a slow, creeping tiredness that many people dismiss as stress or poor sleep.
While iron tablets usually correct the anaemia, the more important question is always why the iron ran low in the first place. For some people the cause is simple (diet or heavy periods); for others, especially older adults and men, low iron can be the first clue to bleeding inside the gut, including bowel cancer. This guide explains the symptoms, how it is diagnosed, and why “finding the cause” matters.
At a glance
| Aspect | Details | What to do |
|---|---|---|
| Common symptoms | Tiredness, weakness, pale skin, breathlessness on exertion, dizziness, fast heartbeat, brittle nails | See a doctor if persistent |
| Common causes | Low dietary iron (vegetarian/vegan), heavy menstrual periods, gut bleeding, pregnancy, NSAID/aspirin-related stomach bleeding | Identify and treat the cause |
| Diagnosis | Full blood count (FBC) and serum ferritin (iron stores); may add iron studies | Blood test ordered by GP |
| Red-flag groups | Men and post-menopausal women with iron-deficiency anaemia; weight loss; blood in stool; change in bowel habit | Needs investigation for GI bleeding/cancer |
| Treatment | Oral iron tablets (often months), iron-rich diet, vitamin C to aid absorption; IV iron in selected cases | Recheck blood counts to confirm response |
What anaemia and iron deficiency actually are
Anaemia is a condition where the level of red blood cells (or haemoglobin) in your blood is lower than normal, so less oxygen is carried around your body. There are several types, but iron-deficiency anaemia is the most common. Iron is the raw material your body needs to build haemoglobin; when iron stores fall, red-cell production suffers.
Importantly, you can be iron-deficient before you are frankly anaemic. This is why doctors often check ferritin (a measure of stored iron) as well as your haemoglobin level.
Symptoms to look out for
Iron-deficiency anaemia often comes on gradually, so symptoms can be easy to ignore. Common signs include:
- Tiredness and weakness that does not improve with rest
- Pale skin (look at the lips, gums and inner eyelids)
- Breathlessness or a pounding/fast heartbeat, especially climbing stairs
- Dizziness or light-headedness
- Brittle or grooved nails, cold hands and feet, and sometimes unusual cravings (e.g. for ice)
These symptoms are not specific to anaemia, which is exactly why a blood test is needed to confirm it.
Why it happens: the causes that matter
Iron deficiency is always caused by one (or more) of three things: too little iron coming in, increased demand, or blood being lost. Common causes in Singapore include:
- Diet: low intake of iron-rich foods, more likely on vegetarian or vegan diets
- Heavy menstrual periods: a very common cause in women of reproductive age
- Pregnancy: the growing baby and expanded blood volume raise iron needs
- Bleeding in the gut: from ulcers, haemorrhoids, or growths such as polyps or bowel cancer; long-term NSAID or aspirin use can cause stomach bleeding
Finding the cause is the whole point. Simply taking iron tablets without working out where the iron went can mask a serious underlying problem.
The red flag: iron deficiency in men and older adults
This is the single most important message of this guide. In a menstruating woman, heavy periods are often the obvious cause. But in men, and in post-menopausal women, there is no monthly blood loss to explain low iron, so unexplained iron-deficiency anaemia is treated as a possible sign of bleeding somewhere in the digestive tract, including bowel (colorectal) cancer.
Warning symptoms that make investigation more urgent include blood in the stool, a persistent change in bowel habit, unexplained weight loss, or tummy pain. In Singapore, the FIT (faecal immunochemical test) and colonoscopy are used to look for the source of bleeding. Please do not self-treat with iron supplements and ignore this — see a doctor so the cause can be found and, if needed, you can be referred.
How it is diagnosed and treated
Your GP will usually start with a full blood count (FBC) and a ferritin level. The FBC shows whether you are anaemic and the size of your red cells (iron deficiency makes them small and pale); ferritin shows whether your iron stores are low. Further tests depend on your age, sex and symptoms.
Treatment has two parts:
- Correcting the iron: usually oral iron tablets taken for several months, often with vitamin C to improve absorption. Intravenous (IV) iron is used in selected cases. Your doctor will recheck your blood to confirm it is improving.
- Treating the cause: e.g. managing heavy periods, stopping unnecessary NSAIDs, or investigating and treating any source of gut bleeding.
Diet: getting more iron from food
Diet supports treatment and helps prevent deficiency, though it rarely corrects established anaemia on its own. Good iron sources include:
- Animal sources (better absorbed): red meat, poultry, liver, fish and shellfish such as clams, sardines, prawns and oysters
- Plant sources: dark leafy greens (e.g. kailan, broccoli), legumes, nuts and dried fruit
Pair plant-based iron with vitamin C-rich foods (guava, papaya, orange, kiwi) to boost absorption. Tea and coffee with meals can reduce absorption. Do not start high-dose iron supplements on your own — confirm the diagnosis with a doctor first, as too much iron can be harmful.
Related guides
- Best GP & Family Clinics in Singapore — our editorial shortlist
- GP & family clinics directory
- Vitamin D deficiency
- Always tired / chronic fatigue
- Unexplained weight loss
Sources
- HealthHub (HPB) – Low In Energy? You Could Be Low In Iron
- HealthHub – Signs and Symptoms of Colorectal Cancer
- HealthHub – Colorectal Cancer: Risk Factors, Symptoms and Screening
- HealthHub – Recommended Dietary Allowances (Singapore)
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