The effects of inflammatory bowel disease (IBD) on the body

Written by: Professor James Lindsay
Edited by: Carlota Pano

In the UK, it is estimated that over half a million people live with inflammatory bowel disease (IBD).


Here, Professor James Lindsay, renowned consultant gastroenterologist based in London, provides an expert insight into IBD. The specialist discusses its causes, symptoms and treatment, among other important points.



What is IBD, and how does it affect the body? What are the symptoms?


IBD is a chronic condition that causes inflammation in the lining of the gut. It comprises two main conditions: ulcerative colitis, where the inflammation is limited to the large bowel (the colon), and Crohn's disease, where the inflammation can occur anywhere within the gut, from the mouth to the intestines and up to the anus.


In terms of the causes, IBD occurs when the immune cells that line the gut - and normally tolerate resident gut bacteria - suddenly become allergic to the normal bacteria in the gut. This allergic reaction causes inflammation, and this inflammation is what drives symptoms.


There’s definitely a genetic tendency, but it's not as straightforward as something like cystic fibrosis where there's a single gene. In fact, there are many genes in IBD - each of which contribute a small amount of risk. There are also key environmental exposures, such as smoking and diet, that play a role in the start and natural history of IBD. Underneath, there are abnormalities within the gut bacteria and within the gut immune system that are also involved.


When patients develop inflammatory bowel disease, depending on the location of the inflammation, they tend to get loose stool or diarrhoea, often containing blood. They may get nasty stomach pains. They may have fevers, lose weight, feel fatigue, and even get inflammation in areas outside of the gut, such as the eyes, the skin, the joints and the liver.


How is a diagnosis made?


To diagnose IBD, there are a series of tests that will need to be organised. These include blood tests to look for: inflammation in the blood; a marker of inflammation in the gut to check for anaemia; and vitamin deficiencies. Sometimes, there are stool tests to exclude infections and to look for inflammation in the stool. These are a common alternative diagnosis.


However, the key tests that allow a diagnosis of IBD to be made are endoscopy, a colonoscopy procedure in which a camera is put inside the bottom and wiggled all the way around the gut to look for inflammation. Imaging with either MRI or ultrasound is also used as a key diagnostic tool for areas of the bowel that are out of reach of a standard endoscope.


How serious is IBD?


IBD has a spectrum of effects on the body. Some patients will have IBD very mildly, with only an occasional flare of the disease.


However, IBD can be much more serious if the inflammation is extensive (spreading through the thickness of the gut) and very severe. Patients can get significant symptoms, and on occasions, require operations to remove sections of damaged gut.


Thus, the severity for an individual patient is very variable, and it may also vary across the natural history (the duration) of the disease.


What are the available treatment options?


When I think about how to treat an individual patient with IBD - be it Crohn’s disease or ulcerative colitis – I have two key goals in mind; the first one is, “I want to get the patient better” and the second one is, “I want to keep the patient feeling better.”


I obviously think about improving all symptoms, but at the same time, it’s also important to heal the lining of the gut. This is because it's the healing of the lining of the gut that prevents future flares of the disease and future disease progression. Likewise, I’m also keen to make sure that every impact that IBD has had on a patient’s life (including their ability to work, their ability to exercise, their fatigue levels, their mood, and even their personal relationships) is reversed. Hence, treatment for IBD is very holistic.


In terms of the strategies that be used, they’re very much dependent on the location and the severity of the disease. These can include tablets, injections, and infusions.


Most of the treatments used for IBD aim to suppress the immune reaction (the response of the immune cells in the gut) to the gut bacteria. The treatments can be very broad-acting, such as drugs like steroids which are very effective but do have a range of side effects, or, many of the newer targeted therapies that are able to improve disease by blocking a single inflammatory pathway and therefore be more effective and also safer.


The correct therapy for each individual patient will depend very much on the location and the severity of the disease, but also on the factors relating to the patient, such as their age, any pre-existing illnesses, any treatments that they may be on, the stage of their life and how the disease is currently affecting them. Treatment for IBD is very much a personalised process.


Can modifications to diet be beneficial?


There are some very specific circumstances where diet can be used to improve inflammatory disease activity. That's only in Crohn's disease, and traditionally, it's a very short-term treatment that's used as a bridge to alternative treatments. This is mainly because the diet involves cutting out the majority of normal foods and replacing them with milkshake-like drinks where the food is already digested.


It’s no surprise to know that what we eat affects how our gut feels and what symptoms we get. Hence, yes, modifications to diet can improve symptoms, both when the disease is active and when the disease is dormant. However, the important thing to remember is that by modifying our diet and improving our symptoms, we may not actually be improving the activity of the disease. It is for this reason, that this kind of strategy always goes hand-in-hand with some form of medical treatment.



Professor James Lindsay is a distinguished consultant gastroenterologist with 25 years’ experience in his field.


If you require expert diagnosis and treatment for IBD, do not hesitate to book an appointment with Professor Lindsay via his Top Doctors profile today.

By Professor James Lindsay

Professor James Lindsay is a renowned consultant gastroenterologist based in London, who specialises in the treatment of digestive issues such as inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and acid reflux. In his twenty-five years of experience, he has also gained bowel cancer colonoscopy accreditation from the National Screening Centre.

After graduating with a degree in medical sciences from the University of Cambridge, Professor Lindsay went on to qualify from the University of Oxford as a bachelor of medicine as well as surgery. He achieved his PhD in mucosal immunology from Imperial College London in 2002, before completing his fellowship with the Royal College of Physicians in 2008.

In addition to his professional experience, he is also passionate about learning and governance in his field. He has been both education officer and governing board member of the European Crohn’s and Colitis Organisation (ECCO). He is currently a member of the International Organisation of IBD (IOIBD) and a national representative for the British Society of Gastroenterology.

He regularly leads pioneering clinical trials and has both written and contributed to numerous medical publications.

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