Vegetarian diet may protect against common bowel disorder

Diverticular disease has been termed a "disease of western civilisation" because of the higher numbers of cases in countries like the UK and the US compared with parts of Africa. The condition affects the large bowel or colon and is thought to be caused by not consuming enough fibre. Typical symptoms include painful abdominal cramps, bloating, wind, constipation and diarrhea.

Previous research has suggested that a low fibre diet could lead to diverticular disease, and that vegetarians may have a lower risk compared with meat eaters, but there is little evidence to substantiate this.

So Dr Francesca Crowe and her team from the Cancer Epidemiology Unit at the University of Oxford set out to examine the link between a vegetarian diet and intake of dietary fibre with the risk of diverticular disease.

Their findings are based on 47,033 generally health conscious British adults who were taking part in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Oxford study. Of those recruited, 15,459 reported consuming a vegetarian diet.

After an average follow-up time of 11.6 years, there were 812 cases of diverticular disease (806 admissions to hospital and six deaths). After adjusting the factors such as smoking, alcohol and body mass index (BMI), vegetarians had a lower risk of diverticular disease compared with meat eaters.

Furthermore, participants with a relatively high intake of dietary fibre (around 25g a day) had a lower risk of being admitted to hospital with or dying from diverticular disease compared with those who consumed less than 14g of fibre a day.

Consuming a vegetarian diet and a high intake of dietary fibre are both associated with a lower risk of diverticular disease, say the authors. The 2000-1 UK National Diet and Nutrition Survey showed that 72% of men and 87% of women were not meeting the recommended average intake for dietary fibre of 18 g per day and so the proportion of cases of diverticular diseases in the general population attributed to a low fibre diet could be considerable, they add.

These findings lend support to the public health recommendations that encourage the consumption of foods high in fibre such as wholemeal breads, wholegrain cereals, fruits and vegetables, they conclude.

In an accompanying editorial, researchers from Nottingham University Hospital discuss the implications for the health of the population and the individual.

Based on these findings, David Humes and Joe West estimate that "about 71 meat eaters would have to become vegetarians to prevent one diagnosis of diverticular disease."

They add: "Overall the opportunity for preventing the occurrence of diverticular disease and other conditions, such as colorectal cancer, probably lies in the modification of diet, at either a population or an individual level." However, they stress that "far more evidence is needed before dietary recommendations can be made to the general public."