3 May 2010 --- Eating more olive oil could help prevent ulcerative colitis, according to a new study co-ordinated by medical researchers at the University of East Anglia (UEA).

Presented today at the Digestive Disease Week conference in New Orleans, the findings show that people with a diet rich in oleic acid – which is present in olive oil –are far less likely to develop ulcerative colitis. Oleic acid is a monounsaturated fatty acid found in olive oil, peanut oil and grapeseed oil, as well as in butter and certain margarines.

The researchers, led by Dr Andrew Hart of UEA's School of Medicine, studied more than 25,000 people aged 40-65 living in Norfolk, UK. The volunteers were recruited to the EPIC study (European Prospective Investigation into Diet and Cancer) between 1993 and 1997. The participants, none of whom had ulcerative colitis at the outset, completed detailed food diaries which were later analysed by specially trained nutritionists working in Cambridge.

By 2004, 22 participants in the study had developed ulcerative colitis and the researchers compared their diets with those who did not develop the disease. They found that those with the highest intake of oleic acid had a 90 per cent lower risk of developing the disease.

"Oleic acid seems to help prevent the development of ulcerative colitis by blocking chemicals in the bowel that aggravate the inflammation found in this illness," said Dr Hart.

"We estimate that around half of the cases of ulcerative colitis could be prevented if larger amounts of oleic acid were consumed. Two-to-three tablespoons of olive oil per day would have a protective effect," said Dr Hart.

Ulcerative colitis is a distressing disease affecting 120,000 people of all ages in the UK and 1 million in the US. It is characterized by inflammation of the lining of the colon or large bowel, which causes abdominal pain, diarrhoea and weight loss.

Similar work in other countries is now required to determine if these results are reproducible there, before the link can be said to be definite. If it is confirmed that oleic acid is truly protective, dietary modifications should be considered to prevent colitis. Additionally, the use of oleic acid supplements should also be assessed in the future as a possible treatment for colitis sufferers.