Ulcerative colitis causes painful ulcers in the colon.
People who have the disorder experience severe abdominal pain, diarrhea, and weight loss.
A study of 25,000 people in the UK found that people whose diet was rich in oleic acid were 90% less likely to develop the digestive disorder.
Researchers say 2 to 3 tablespoons of olive oil each day would have a positive effect.
The results of this study were presented over the weekend at the Digestive Disease Conference in New Orleans.