What is Inflammatory Bowel Disease and what causes it?

Inflammatory Bowel disease is a complicated condition. Many people have heard of it and perhaps even know of someone who has it, but do not necessarily understand what it is. So let us break it down and try and make it less complicated.

What is Inflammatory Bowel disease?

Inflammatory Bowel disease consists of two conditions: Crohn’s disease and ulcerative colitis.

Both of these diseases share some common similar features.  They cause inflammation in the GI tract (gut).  Inflammation is where the inside of the gut becomes red and sore almost as if you had a burn on the skin.  Both conditions cause inflammation in the bowel but they are different in the places that they cause it.  Both conditions are also categorised by periods when the disease is active and patient have symptoms and periods when the disease is quiet (or quiescent or in remission).  During these times patients usually have very few or no symptoms at all.

Click here to find out more about colitis.

What is Crohn’s disease?

Crohn’s disease causes inflammation anywhere in the gut. This extends from the mouth all the way to the bottom. It usually causes separate patches of inflammation dotted throughout the gut and these are known as skip lesions as there is normal gut in between each patch of inflammation. In the mouth Crohn’s disease usually causes ulcers. Around the bottom area it often causes abscesses. In between it causes patches of ulceration where there is a break in the lining of the gut.

What are the symptoms of Crohn’s disease?

Crohn’s disease often causes diarrhoea.  This can mean that the stool becomes more liquid or that you need to go to the toilet more often.  There may also be passing of blood with the stool.  This can be very marked with patients having to go to toilet more than 10 times a day.  They may also have to get up in the night to go to the toilet.

Crohn’s disease commonly causes abdominal pain.  This can be quite severe and stop you from sleeping or stop you leading your normal daily life. Extended periods of both diarrhoea and abdominal pain can lead to weight loss due to the lack of desire to eat.  You may also feel generally unwell.

If you develop these kind of symptoms they should always be investigated, so you should go and see your GP or of course at OneWelbeck we would be happy to support you in the investigation of these symptoms.

Who gets Inflammatory Bowel disease?

Anyone can get Inflammatory Bowel disease. Most often it starts when you are either in your teenage years or a young adult. It can interfere with work and your social life and make things very difficult. So it is important that if you have these symptoms you have them checked out to make the diagnosis and start effective treatment.

What causes Inflammatory Bowel disease?

The truth is we do not really know exactly what causes Inflammatory Bowel disease but we do know that some things play a role.


We know that if someone in your family has inflammatory bowel disease it is more likely that other members of your family will develop inflammatory bowel disease.  This suggests that some people carry something in their genes which pre-disposes them.  The strongest example of this is in identical twins.  In identical twins, if one has Crohn’s disease, two-thirds of the other twins will also develop Crohn’s disease. If a member of your family has inflammatory bowel disease, then the chance of you developing Crohn’s disease or ulcerative colitis is around 10%.

We now know a lot about the genes which increase your risk of developing inflammatory bowel disease.  There are lots of genes (more than 100) each of which can play a small role in increasing your risk.  These genes affect many different systems in your body and it reflects the complicated nature of inflammatory bowel disease.  No one gene causes inflammatory bowel disease but your risk is increased if you carry lots of these particular genes, each of which causes a small increase in risk.  The surprising thing is that many of these genes are shared with other diseases which you might not expect.  Other autoimmune diseases (diseases where the body’s immune system plays a role in the development), such as diabetes and rheumatoid arthritis share some of the genes.  Unfortunately, because the genes are so complicated we cannot yet test individuals to see whether or not they will develop inflammatory bowel disease.

Environmental factors

For most people genetics only plays a small role in the development of inflammatory bowel disease.  We think the rest is due to something in the environment but we do not really know what that is.  We do however have some ideas.

  • Diet: We do not really know what it is in the diet which might cause inflammatory bowel disease.  We do however, think that a poor diet with lots of processed foods and high sugar and fat may be associated with inflammatory bowel disease.  For this reason, along with many other reasons, you should try and eat a healthy diet with lots of fruit and fibre and non-processed foods.
  • Bacteria in the bowel: We each carry millions of bacteria in our bowel.  Each of us has a unique pattern of bacteria which we call our bacterial flora.  We know that in patients with inflammatory bowel disease the bacterial flora changes.  Patients with inflammatory bowel disease tend to have fewer kinds of bacteria in the bowel and sometimes have more of a particular kind present.  However, we do not really know if this causes the development of the disease or whether it is as a result of having the condition.  This is a huge area of research and hopefully we will know more in the years to come.
  • Smoking: We know that if you smoke you are more likely to develop Crohn’s disease.  We also know that if you  smoke, the treatment that you receive for Crohn’s disease is less likely to work.  For this reason we tell all patients with Crohn’s disease that they must stop smoking.  It is another good reason why smoking is not good for you.  Unusually, smoking does seem to reduce your risk chances of getting ulcerative colitis.  However, this is outweighed by all the damage that smoking can cause to your heart and lungs, so we would never advise a patient to start smoking for their ulcerative colitis.
  • Psychological stress: Lots of patients with inflammatory bowel disease tell us that their disease is made worse by stress.  Some patients also think that they developed inflammatory bowel disease after particular periods of stress.  However, the situation is always very complex as everybody’s life is stressful and it is often easy to remember a particular time as being stressful looking back when you were having a flare or after developing a disease.  We do, however, think that on balance stress probably does play a role.  But the other challenge is that with modern living, it is extremely difficult to remove all the stress from our lives, so this is rarely something we can use as a treatment.
  • Living in the modern world: We think that Inflammatory Bowel disease is more common in developed countries than in developing countries.  The cause for this is not known.  Lots of different things have been suggested as possibly being the cause for this difference.  Some people have proposed that perhaps refrigerated foods, or micro particles which are found in substances such as toothpaste, or sulphur containing foods might be a risk factor.  The reality is, however, that we do not really know if any of these are true as it has been very difficult to prove.


Inflammatory bowel disease is complicated.  Both Crohn’s disease and ulcerative colitis are challenging diseases to understand and at the moment we do not have a complete picture of what causes them.  We do have however, some ideas as outlined above.  But it is true to say that in recent years we have made huge progress in understanding the condition and this will continue as more research is undertaken and our understanding increases.  Hopefully this will then lead to new treatments and allow us to provide better care and control of the condition.

What we do know is that if you develop any of the symptoms I have described above, such as abdominal pain, diarrhoea or rectal bleeding, particularly if there is associated weight loss or being generally unwell, you should definitely consult your GP.  Here at OneWelbeck we would be happy to support you in investigating your symptoms to find the root of your problem which will then allow us to start treatment and return you to health.

Get in touch

If you would like to speak to one of our specialists about Inflammatory Bowel disease, or any other concerns you might have regarding your digestive health, please do not hesitate to get in touch with us today.

You can easily book online, or simply contact us through our online form or via telephone.