If you have inflammatory bowel disease (IBD) your risks increase of also having iron deficiency and iron deficiency anaemia.

IBD is the name for a group of conditions where your gastrointestinal tract (your small and large intestines) becomes inflamed. The two most common forms of IBD are Crohn’s disease and ulcerative colitis (UC)1. In the UK and the USA, around 1 in 250 people have IBD2,3. The exact cause of IBD is unknown but it is thought that many factors are involved, including smoking, previous infections, and genetics4.

Anaemia is the most common non-intestinal symptom of IBD5. Anaemia is where the number of red blood cells in your body, or the amount of oxygen that they can carry, is too low for your body’s needs. Anaemia can occur for many reasons, however the most common reason for anaemia in IBD is iron deficiency5

If you have IBD of any kind you are at risk of iron deficiency and iron deficiency anaemia (IDA)6. Different studies have calculated the number of people with IBD and iron deficiency anaemia differently, but they suggest that 36%–76% of people with IBD experience iron deficiency anaemia7. The main reasons why you may experience iron deficiency or iron deficiency anaemia with IBD are:

  • Long term internal bleeding within the intestines
  • Reduced iron absorption from your diet due to inflammation in your intestines
  • Reduced dietary intake of iron, if you avoid eating certain foods such as leafy greens because they increase your IBD symptoms1

Although iron deficiency is the most common cause of anaemia in IBD5, there are also other reasons that you might become anaemic such as:

  • Anaemia of chronic disease (inflammation)This type of anaemia is caused by your body’s immune system8. With this type of anaemia, some of the iron that is present in your body is not available for the production of haemoglobin for your red blood cells8. This means that fewer red blood cells are produced. Also, the life span of your red blood cells can be reduced8.
  • Anaemia of vitamin deficiencies For example, due to decreased absorption of vitamin B12 or folic acid1. Anaemia from vitamin deficiencies occurs if you do not eat enough food containing vitamin B12 and folic acid, or if you have not absorbed these nutrients from your food in your intestines. This type of anaemia may be more likely if you have Crohn’s disease as the sections of the small intestine where these nutrients are usually absorbed may be inflamed, or may have been surgically removed8.
  • Drug-induced anaemia For example, anaemia caused by IBD treatments, such as sulphasalazine and azathioprine8, that supress the production of blood cells1.

It is important to treat your anaemia, whether this is due to iron deficiency or any of the other reasons mentioned above.

Iron deficiency can lead to a reduced ability to work, and if symptoms are severe, can cause an extended hospital stay5. Treating iron deficiency or iron deficiency anaemia with extra iron can improve your mental and physical function, making you feel more energetic and generally improving your quality of life.

If you think that you might be iron deficient or you are concerned about your health in any way, it is important that you talk to your doctor. Your doctor will be able to find out whether you are anaemic and, if you are, what the causes behind it are and how it can be treated.