Digestive health centre

High-fibre and meat-free diets may lower risk of bowel disease

By Sophie Ramsey

BMJ Group News

What do we know already?

If you have diverticular disease, small pouches have formed in your bowel wall causing symptoms such as painful cramps, wind, and bloating. These pouches can sometimes become infected or cause other complications, which can be serious.

Diverticular disease is often called a ‘disease of Western civilization’ as it’s more common in the UK and other Western countries than in parts of Africa. Most experts think the difference relates to diet.

In particular, people in the UK and similar countries tend to eat more meat and less fibre, which comes from whole grains, fruits, and vegetables. These eating habits can slow digestion and make constipation more likely. This can put more pressure on the bowel wall, which may increase the chance that pouches will form.

However, not many studies have looked at whether eating a high-fibre or meat-free diet might protect from diverticular disease. To explore this, UK researchers used questionnaires to assess the diets of more than 47,000 adults, and then tracked who developed diverticular disease over 12 years, on average.

What does the new study say?

Vegetarians and people eating high amounts of fibre were less likely to develop diverticular disease during the study. After adjusting for factors such as alcohol intake, smoking, and body mass index (BMI), the researchers found that vegetarians had a 31 percent lower risk of diverticular disease than meat eaters. And, people consuming the most fibre had a 41 percent lower risk compared with those consuming the least.

These declines in risk with high-fibre and vegetarian diets were independent of one another, meaning that vegetarians still had a lower risk of diverticular disease after researchers took account of how much fibre they ate, and vice versa.

How reliable are the findings?

This study supports findings from another large study looking at high-fibre diets, and smaller trials on meat and diverticular disease. This makes its results more compelling.

However, the study can’t prove that people had a lower risk of diverticular disease because they ate a high-fibre or vegetarian diet, as there might have been other things that affected their risk. For example, the researchers didn’t factor in whether participants had been using medicines linked to diverticular disease.

Also, the people in the study were described as ‘generally health conscious’, so they might have exercised more than average, eaten a healthier diet overall, or taken other steps to maintain their health. As a result, the findings might not apply to people who aren’t so health-aware.

What does this mean for me?

This study lends support to government recommendations that people eat a diet rich in fruits, vegetables, wholegrain breads, and other high-fibre foods. Although the link with diverticular disease still needs more research, we do know that these foods play an important role in good nutrition and digestion overall.

The researchers don’t recommend that people adopt a vegetarian diet purely to lower their risk of diverticular disease. Indeed, based on these findings, about 71 meat eaters would need to become vegetarians to prevent one diagnosis of diverticular disease. However, if you’re considering adopting a meat-free diet for other reasons, these findings may provide additional incentive.