Diverticular disease: Common gut condition you've probably never heard of

It’s not something people often talk about at the dinner table, but your gut health plays a huge role in your overall wellbeing. And one of the most common conditions affecting the large intestine is diverticular disease.

Diverticular disease or diverticulosis is where small bulges or pouches (called diverticula) form in the wall of the colon, often due to a weakening in the muscle layer. These pouches are usually harmless, but in some cases they can become inflamed or infected – a condition known by the slightly different name of diverticulitis.

Around 70% of people in western countries will have developed diverticular disease by the time they reach 80. It’s also increasingly showing up in younger adults, which may be linked to the low-fibre, highly processed nature of many modern diets. UK dietary surveys show that people are currently consuming only 60% of their recommended daily fibre intake.

The reasons some people develop diverticular disease and others don’t aren’t fully understood. However, several factors have been identified as contributors, including the structure and movement of the colon, diet, fibre intake, obesity, physical activity and genetics.

Most people with diverticular disease don’t experience symptoms. However, some may report pain or discomfort in the lower left side of the abdomen – often worse after eating – as well as bloating, diarrhoea or constipation. These symptoms can mimic other digestive disorders such as irritable bowel syndrome (IBS), making diagnosis more complex. 

Despite how common it is, diverticular disease is often misunderstood. Many people have no symptoms at all, while others experience ongoing digestive discomfort.

Diverticulitis (when diverticula in the colon become inflamed or infected) is usually marked by more severe symptoms, including constant abdominal pain, a high temperature, nausea, and in some cases, changes in bowel habits. These symptoms warrant urgent medical attention, as untreated diverticulitis can lead to complications.

Thankfully, small changes in diet and lifestyle can make a big difference and outdated advice is quickly being replaced by evidence based recommendations. Historically, people with diverticular disease were told to avoid foods like nuts, seeds and popcorn out of fear that they might get stuck in the diverticula and cause inflammation. However, this idea has now been debunked.

Updated guidance from the National Institute for Health and Care Excellence confirms there is no need to avoid these foods unless specifically advised to do so by a healthcare professional.  What does help is a high-fibre diet. Fibre softens stools and makes them easier to pass, which helps reduce pressure in the colon and prevent constipation – one of the known risk factors for diverticulitis. When stools are small and hard, they may become lodged in the diverticula, increasing the chance of inflammation or infection.

In addition to eating more fibre, staying well hydrated and being physically active also support healthy digestion. Water helps fibre do its job, while regular movement can encourage normal bowel function and reduce the risk of complications.

If you’re unable to meet fibre targets through food alone, your doctor or dietitian may recommend fibre supplements or mild laxatives.

Official UK guidance advises adults to eat at least 30g of fibre per day. Some simple ways to do this include starting your day with a high-fibre breakfast cereal and adding fresh or dried fruit. Switching to wholemeal or granary breads, choosing wholewheat pasta or brown rice, and including more lentils, chickpeas, beans and vegetables in your meals can all help.

For example, grated carrot, red lentils or kidney beans can easily be added to mince-based dishes, while raw vegetables such as peppers or carrots work well with dips like hummus or guacamole.

When increasing your fibre intake, it’s best to do so gradually. A sudden jump in fibre can cause bloating or gas, so give your digestive system time to adapt.

By making small, sustainable changes to your diet and lifestyle – like eating more fibre, staying hydrated and moving your body – you can reduce your risk of discomfort and complications. With up-to-date medical advice and a balanced approach to nutrition, it’s entirely possible to keep your gut happy, healthy and functioning well for years to come.