Iron Deficiency Anaemia

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What is Anaemia?

What is Anaemia?

Anaemia is a common condition in Singapore caused by an abnormally low amount of red blood cells. Red blood cells have a protein called haemoglobin that helps carry oxygen via the bloodstream from our lungs to all our tissues, allowing us to go about our daily lives normally.

Anaemia has a wide variety of causes and may or may not be symptomatic, depending on how low the red blood cell counts are. Broadly, the causes of anaemia include:

  • Insufficient haemoglobin production (iron deficiency anaemia, thalassemia)
  • Production of abnormal haemoglobin (various haemoglobin disorders)
  • Insufficient red blood cell production (chronic infections, bone marrow diseases, alcohol use)
  • Increased breakdown of red blood cells (sickle cell anaemia)

What is Iron Deficiency Anaemia?

Illustration of General Circulation

Iron deficiency anaemia is the most common cause of anaemia worldwide, caused by insufficient iron stores in the body, leading to the inadequate synthesis of haemoglobin. 

Causes of iron deficiency anaemia include:

  • Increased blood loss — this can be from menstruation or chronic blood loss from other sites such as ulcers, tumours, polyps, etc.
  • Low dietary intake of iron — picky eaters/children, vegetarians, or people living in less developed countries are at higher risk
  • Iron malabsorption — those with intestinal diseases, intestinal surgery or malabsorption may not be able to absorb sufficient iron from digested food
  • Pregnancy — the foetus uses the mother’s iron supply to synthesise its own haemoglobin, and the mother’s blood circulating blood volume increases during pregnancy, requiring more haemoglobin production as well

Who is at risk of developing Iron Deficiency Anaemia?

Some groups are at a higher risk of developing iron deficiency anaemia:

  • Women, especially those with heavy or frequent menstruation or pregnant women not on iron supplementation
  • Children who happen to be picky eaters and are not willing to eat iron-rich foods such as green leafy vegetables, meat, eggs
  • Vegetarians may be at a higher risk, depending on the type and quantity of vegetables they consume
  • Frequent blood donors, since blood donation requires the body to synthesise more red blood cells to replace what was donated

What are the Symptoms of Iron Deficiency Anaemia?

Depending on the severity of iron deficiency anaemia, it can range from being completely asymptomatic to concerning symptoms such as chest pain.

Common signs and symptoms of iron deficiency anaemia include:

  • Weakness
  • Fatigue 
  • Decreased ability to concentrate
  • Noticeably pale skin, lips, and eyelids
  • Giddiness or lightheadedness
  • Decreased ability to exercise
  • Headaches

In more severe cases, you may even experience:

  • Chest pain, shortness of breath, increased heart rate
  • Reddish, painful & swollen tongue
  • Brittle nails
  • Pica — cravings for ice, paper, soil, or other non-nutritious substances

The ‘anaemia eyes’ test

You may have heard of the ‘anaemia eyes’ test, a quick self-examination that can be performed in seconds — all you need is a mirror. Pull your lower eyelids down such that the inner side is visible. In a non-anaemic person, it should be pinkish red, but if you have anaemia, it may appear pale pink or yellowish-white.

Can “anaemia tongue” point to iron deficiency anaemia?

Anaemia tongue refers to glossitis, a condition directly related to low iron levels. It manifests with several noticeable symptoms: 

  • Painful, tender & swollen tongue
  • The reddish appearance of the tongue
  • Difficulty in speaking, chewing or swallowing
  • Smooth appearance of the tongue due to loss of tongue papillae (the small bumps visible on a normal tongue)

How is Iron Deficiency Anaemia Diagnosed?

As the name suggests, one is diagnosed with iron deficiency anaemia after various blood tests come back with results indicating both a low iron level and low red blood cell count. In iron deficiency anaemia, a full blood count and iron panel are done. The full blood count will reveal smaller & paler red blood cells, while the iron panel will reflect low iron levels and ferritin, a protein that helps store iron in your body.

Additionally, further tests may be done to identify an underlying cause, such as bleeding from various sites, tumours or ulcers.

An endoscopy may be done. It involves inserting a flexible, thin tube down one’s throat, with a camera attached to the end, enabling direct visualisation of the appearance of your upper gastrointestinal tract (including the stomach & duodenum) and sampling of your tissue if required. Similarly, a colonoscopy may be offered. It involves the insertion of a flexible tube with a camera into the rectum and guided upwards into the colon. Any ulcers, bleeding, or abnormal masses suggestive of an underlying cause can be readily identified.

Apart from symptoms, doctors will also need to know about the kind of medications or supplements you are taking, as the iron supplements prescribed in the treatment of iron deficiency anaemia may decrease the efficacy of some of your medications.

How can I check my iron levels at home?

Conventionally, iron levels are checked during routine visits to the doctor. However, if your doctor advises you to check your levels at home, there are various test kits that allow you to do it yourself at home.

There are various brands on the market, but in general, they involve obtaining a small sample of your blood (using a small lancet included in the kit) and placing it into the test cassette. It is rather similar to checking one’s own blood sugar in diabetic patients, and the cassette resembles COVID self-test kits.

The results of the test should always be interpreted under the guidance of a doctor.

How is Iron Deficiency Anaemia Treated?

iron deficiency treatments

Treatment involves both replacing the iron as well as identifying the underlying cause.

Iron replacement comes in the form of a tablet or liquid and, less commonly, can also be given intravenously. To maximise absorption, your doctor will recommend staggering the timing of taking your food and iron supplements:

  • Take your iron supplements on an empty stomach, or if it causes gastric discomfort, take it right before a meal
  • Take iron in combination with Vitamin C or Vitamin C-containing food/drinks, as it increases iron absorption
  • Do not take iron at the same time as antacids, as they decrease iron absorption. If you require antacids, be sure to take them either two hours after or four hours before iron supplements

Additionally, eating iron-rich foods such as meat, eggs, leafy green vegetables can help boost your body’s iron stores. For children who may be picky eaters, there are special iron-fortified cereals available as well.

Depending on the underlying cause of iron deficiency anaemia, management may range from medications to reduce heavy menses to the treatment of any sites of bleeding or ulceration in the gastrointestinal tract, etc.

How long does it take to get Iron levels up?

It generally takes 2 to 3 weeks of consuming iron supplements before showing improvement of symptoms. Supplementation may be continued for a few months to ensure adequate stores of iron in your body so the iron deficiency anaemia does not recur.

Constipation and greyish-black stools are the most common side effects associated with iron supplementation, but constipation can be managed with laxatives. Overall, the benefits of iron supplementation outweigh the side effects, and you should continue taking them until the doctor has confirmed that your iron stores have been replenished.

Is Iron Deficiency Anaemia Permanent?

Depending on the cause, iron deficiency may or may not be permanent. In easily treatable causes like heavy menstrual bleeding or dietary shortages, treating the root cause will likely cure the anaemia. However, in causes related to chronic blood loss from various sites in the body, the resolution of iron deficiency anaemia largely depends on how effectively the cause can be addressed.

What happens if Iron Deficiency Anaemia is not treated?

If left untreated, iron deficiency anaemia can have a significant impact on your health. A low blood count can put you at increased risk of heart attacks, fast heartbeats (tachycardia) and a decrease in your ability to exercise normally. Additionally, low iron decreases your immunity and increases your risk of getting infections.

In pregnancy, severe iron deficiency anaemia increases the risk of a premature baby (born before 36 weeks). It is also associated with postpartum depression in the mother.


In conclusion, iron deficiency anaemia is a very common cause of anaemia and may have an impact on your health if left untreated. Fortunately, it is treatable with a combination of supplements and management of the underlying cause(s).

If you have the symptoms mentioned above or feel you may be at risk of iron deficiency anaemia, do make an appointment with your Gastroenterologist to have your blood tested and to obtain a diagnosis.



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Dr Benjamin Yip

Consultant Gastroenterologist
MBBS (Singapore), MRCP (UK), MCI (NUS), FRCP (Edin), FASGE (USA), FAMS (Gastroenterology)

Dr Benjamin Yip is a Consultant Gastroenterologist and the Medical Director of the Alpha Digestive & Liver Centre.

Dr Yip believes that gastrointestinal health is hugely interconnected to our whole-body health and sees patients with General Medical, as well as Gastroenterology and Hepatology problems.

His expertise lies in Advanced Endoscopy, including complex endoscopic procedures such as ERCP, EUS, single balloon enteroscopy, Spyglass cholangioscopy and enteral dilation/stenting.

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