Medical advice

Why do we think that eating a Western diet causes diverticular disease?

Fibre is roughage – that part of our diet that we can’t digest and which passes through us. The more fibre we eat, the larger our stools. So if we don’t eat much fibre, this means we pass rather smaller stools. Just like it becomes harder to squeeze toothpaste out of the tube when there is not much toothpaste left, so the smaller the stool, the harder the intestine has to squeeze to push it along. Over many years, this high pressure pushes out the lining of the intestine through its outer wall to form the pouches that result in diverticular disease.

Can the development of diverticula be prevented?

It is not possible to answer this question. Such evidence as we have suggests that the best chance of avoiding diverticula is to increase the proportion of fruit, vegetables and cereals in the diet. This seems wise but there needs to be a long-term and sustained change in an individual’s eating habits in order to reduce the chance of getting diverticular disease. Of course, there seem to be several other health benefits of a high-fibre diet.

What are the symptoms of diverticular disease?

Some people experience persistent abdominal symptoms such as pain, often quite low down in the left side of the abdomen, together with bloating and an irregular bowel habit. Patients may be constipated whilst others have diarrhoea. Some have an irregular bowel habit with constipation for a period followed by days when they have diarrhoea. It can be very unpleasant if you need to reach a toilet in a hurry. Nevertheless, the pattern of symptoms does vary from one person to the next.

What complications can occur?

Complications are fairly uncommon. When a diverticulum or several diverticula become inflamed, this leads to diverticulitis which causes unpleasant pain, fever and a feeling of being quite unwell. If the inflammation is exceptionally severe, the diverticulum can burst which can lead to peritonitis –a serious condition with widespread inflammation within the abdomen. Sometimes, scar tissue can form around the inflamed diverticulum. This may lead to narrowing of the colon which, if it becomes narrowed enough, can cause a blockage. A blood vessel in the wall of a diverticulum can rupture leading to bleeding into the colon. Most people with diverticular disease never get any of these complications. 

How is the diagnosis of diverticular disease made?

In essence, the doctor needs to see what your colon looks like. The most frequent way of doing this nowadays is by passing a tube through the back passage to visualise the inner surface of the colon (sigmoidoscopy or colonoscopy – depending on how much of the intestine that the doctor wishes to see). Alternatively, a barium enema X-ray is a reliable method of showing whether there are diverticula. Both techniques will require you to take something to clear out the bowel beforehand. It is very important that the doctor looks carefully for any other abnormalities that might cause your symptoms. This is because diverticula are common and they may be quite incidental – in other words, they are there but they are unlikely to be the cause of your symptoms.