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Understanding iron deficiency and iron deficiency anaemia

Iron deficiency (ID) is a condition in which the body does not have as much iron as it needs. Iron deficiency anaemia (IDA) is a more severe form of ID where the lack of iron stops the body from working as well as normal. They are both very common.1,2

ID affects about 1 in 4 people across the world2,3

IDA affects about 1 in 6 people across the world1,3

What is iron used for?

Iron is an important mineral. The body uses iron in lots of ways to keep itself working properly.

The main way iron is used is to form a protein called haemoglobin. Red blood cells use haemoglobin to carry oxygen to all the body’s organs and tissues.

When the body does not have enough iron, it cannot make as much haemoglobin and as many red blood cells as normal. The red blood cell level will start to drop because the old cells cannot be replaced quickly enough, and the new red blood cells that are made will be smaller than usual. This means less oxygen can be carried around, causing the symptoms you may be feeling.


Why don't I have enough iron?

The body contains 3–5 g of iron, and each day it needs 20–25 mg of iron to build new red blood cells and keep itself working properly. Most of this comes from recycling the iron that is already in your body, and 1–2 mg is absorbed from food.1

Your body is normally good at balancing the amount of iron it takes in from food with the amount it loses. But sometimes it can go out of balance. Some of the most common reasons this happens are:4,5

Diets low in iron – there is not enough iron in the diet for the body to replace what it is normally losing

Heavy periods – the body loses iron each month that it finds hard to replace                                        

Pregnancy – the body makes more blood for itself and the baby, and the baby needs extra iron to grow

Taking certain medicines such as ibuprofen or aspirin                                                                      

Other conditions that can cause ID/IDA include:4,6,7

Inflammatory bowel disease – gut inflammation and irritation can cause blood loss and can reduce the amount of iron that can be absorbed

Stomach ulcers – the body can lose iron due to bleeding from the ulcer

Chronic kidney disease – the body may not absorb or retain as much iron as usual, and iron can also be lost during haemodialysis



Are there ways to get more iron?

If you have ID/IDA symptoms, you should speak to your doctor. They may carry out tests to see whether you have ID/IDA, and if you do, decide how you should get more iron.

There are two ways of getting more iron.

Changing your diet
You can eat more foods that contain high levels of iron or that improve how much iron you can absorb.


Foods that are high in iron include:

  • Dark-green leafy vegetables like broccoli, curly kale and spinach
  • Dried fruit such as raisins and apricots
  • Cereal, bread and pasta made with extra iron in them (fortified)
  • Red meat, pork and poultry
  • Fish, especially shellfish, sardines and anchovies
  • Pulses like beans, peas and lentils

Taking a supplement or medicine containing iron
If you are diagnosed with ID/IDA, you may be prescribed a supplement or medicine containing iron.


If your ID/IDA is mild, you may be recommended to take an iron supplement that you can buy from a pharmacy without a prescription. If you need more iron, you may be prescribed iron medicine (tablets or liquid) instead. And if your ID/IDA is more severe, or if the tablets do not work, you may need intravenous iron into your vein.6




  1. Lopez A, et al. Lancet 2016;387(10021):907–916.
  2. Camaschella C. Hematology Am Soc Hematol Educ Program 2015;2015:8–13.
  3. UK Gov Trend Deck 2021: Demographics. Available at: Accessed December 2021.
  4. Mayo Clinic. Iron deficiency anemia. Available at: Accessed December 2021.
  5. NHS. Iron deficiency anaemia. Available at: Accessed December 2021.
  6. American Society of Hematology. Iron deficiency anemia. Available at: Accessed December 2021.
  7. Cleveland Clinic. Intravenous Iron Supplementation. Available at: Accessed December 2021.