Researchers in Denmark have confirmed that a chemical found in raw carrots and other vegetables helps to prevent colon cancer - although it is not the same substance that scientists had previously thought responsible. Experts used to believe that it was the beta carotene found in carrots that had an inhibitory effect on cancer, but research carried out at the University of Southern Denmark shows that it is actually the plant chemical falcarinol. Falcarinol is also found in celery, parsley, parsnip and other vegetables, but only when raw. Cooking destroys the cancer preventing properties of falcarinol, the researchers say. Morten Larsen, who headed the research, says: 'The discovery makes it possible for us to authoritatively recommend which vegetables should be eaten to protect against cancer. With more research, we hope we can give more precise recommendations on the amount of carrots and other vegetables a person should eat daily.' Dr Larsen conducted his research in collaboration with the Danish Institute of Agricultural Sciences, which is trying to develop methods for growing carrots with higher levels of falcarinol, and studying what happens to the chemical when vegetables are cooked or frozen. 'We know the effect is greatest when carrots are eaten raw, and we know that falcarinol is very sensitive to light and heat, so cooking has a negative effect. It looks kike freezing will preserve the cancer-preventive effect, so we can expect that frozen carrots are also beneficial,' Dr Larsen added. Colon cancer is the second most common cancer in the EU, and there is currently no cure once it has become symptomatic, so testing and early detection are crucial.