They found consumption of brassica vegetables such as Brussels sprouts, cabbage, cauliflower and broccoli decreased the risk of cancer in the proximal colon – the first part of the large intestine.
These vegetables (also known as cruciferous vegetables) are high in fibre, vitamin C, antioxidants and other micronutrients, and have previously been identified as reducing the risk of various cancers.
Dark yellow vegetables and apples were found to be associated with a reduced risk of cancer in the distal colon, which is closer to the rectum. Both total fruit and vegetable intake and total vegetable intake also appeared to decrease the risk.
"Fruits and vegetables have been examined extensively in nutritional research in relation to colorectal cancer, however their protective effect has been subject to debate, possibly because of different effects on different subsites of the large bowel," said lead researcher Professor Lin Fritschi.
However while fruit and vegetable intake was clearly beneficial in terms of bowel cancer risk, the same does not apply to fruit that is processed and consumed as juice.
The study found high consumption of fruit juice increased the risk of cancer in the rectum.
The results were based on food intake surveys from almost 1,000 people with bowel cancer and 1,000 people without bowel cancer. The research is published in the October issue of the Journal of the American Dietetic Association.