Scientists have found evidence to suggest that vegetables like cabbage and sprouts may fight colon cancer.
Eating sprouts may protect against cancer
Experts at the Institute of Food Research have discovered that a chemical called AITC is released when brassica vegetables are prepared.
This chemical can kill colon cancer cells and is able to stop the disease from spreading.
The scientists said eating these vegetables two to three times a week could protect against the disease.
AITC is created when brassica vegetables are chopped, chewed, cooked, processed and digested.
AITC is a breakdown product of sinigrin, a chemical compound found in brassica vegetables.
These include mustard, cabbage, horseradish, cauliflower, sprouts, swede, kale and wassabi.
Professor Ian Johnson, who led the research, said the findings show how diet can protect against cancer.
"This is not a miracle cancer cure, but it does show that preventive dietary measures can be discovered and exploited in the same way as drugs."
The findings come as the World Cancer Research Fund announced plans to carry out the world's biggest study into diet and cancer.
Scientists from around the world will review more than 10,000 pieces of research as part of the study.
They aim to come up with clear guidance on what foods people should eat to protect against cancer and clear up any confusion there may be. The findings are due to be published in 2006.
Researchers at the universities of Leeds and Bristol will collate information on cancers of the pancreas, stomach, bladder, prostate and kidney.
Experts at Pennsylvania State University in the United States will look at cancers of the mouth and throat.
Another team at Johns Hopkins University in Maryland will examine cancers of the lung and upper throat, while researchers at Kaiser Permanente in California will investigate cancer of the uterus.
Scientists in The Netherlands have been lined up to look at the data on cancers of the colon, rectum, liver and gallbladder. Italy's National Cancer Institute will examine breast, ovary and cervical cancer.
"This is an enormous undertaking," said Professor Martin Wiseman, project director and WCRF medical and scientific adviser.
"The goal is to cut through the widespread confusion about diet's relation to cancer risk by producing a comprehensive report that offers simple, science-based recommendations for individuals and policy makers."
Professor Wiseman said the study would provide a clear overview of what is known about diet and cancer.
"Most people assume that cancer is either all about luck or all in the genes, but neither is entirely the case," he said.
"When a new study hits the headlines it sometimes seem to contradict or complicate previous results, so it's easy for people to grow confused, frustrated, even apathetic.
"That's why we are asking these leading research centres to take a step back and to help us look at the evidence - at all of the evidence - from a truly global perspective."