Cancer-combating chemicals from veg
or otherwise processed could kill colon cancer cells - new evidence
that diet could play an important role in fighting - and indeed
preventing - the disease.
Scientists at the Institute of Food Research (IFR) in the UK found that natural chemicals released by brassica vegetables such as cabbage or broccoli can 'sabotage' the uncontrolled cell division of colon cancer cells, acting in much the same way as many anti-cancer drugs.
ISR scientists found that the plant chemical allyl-isothiocyanate (AITC) - a breakdown product of sinigrin, a chemical compound found in brassica vegetables including mustard, cabbage, horseradish, cauliflower, sprouts, swede, kale and wasabi - affected the cancerous cells as it was released when the vegetable was processed, either by chewing, chopping or cooking.
Unlike normal cells, which 'commit suicide' at the end of their lifecycle, cancer cells continue to divide indefinitely. Cell division occurs when a parent cell divides to form two daughter cells during a four-stage process. In the second stage, known as metaphase, pole structures called spindles are created. Anything that disrupts the construction and deconstruction of these spindles halts the process of cell division. Previous studies have shown that damaged cells then commit suicide in a process called apoptosis.
"This is the first time the disruption of metaphase by an isothiocyanate has been explored in detail in relation to colon cancer prevention," said Professor Ian Johnson, head of the IFR's Gastrointestinal Health and Function research group.
"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," he said. "We have known for many years that sinigrin breakdown products kill cancer cells. But by uncovering a previously unknown part of the process working in a similar way to some anticancer drugs, we hope to show how important diet can be in your personal anticancer armoury."
Professor Johnson explained that AITC appeared to selectively target tumour cells, unlike some other chemotherapeutic drugs that also harm healthy cells. However, he stressed that the mechanism needed further investigation.
Most cancers are not genetically inherited, and it is widely accepted that 30 per cent to 70 per cent are preventable through changes to diet, the IFR researchers suggested, adding that natural plant chemicals such as AITC could provide protection and even treatment against other cancers of the gastrointestinal tract (stomach, pancreas, oesophagus, as well as colon) and of the lung.
The IFR research will be published in the journal Carcinogenesis in July, and was announced at the Science Media Centre in London yesterday, alongside a new report by the World Cancer Research Fund to be published in 2006.
Professor Martin Wiseman, medical and scientific adviser to WCRF, said: "This is a valuable piece of research that puts in place another piece of the jigsaw on the way in which foods and nutrition could influence cancer risk. These sorts of studies, together with other types of study, contribute to a greater understanding of the role lifestyle plays in cancer prevention.
"Our 'portfolio' approach allows us to take all different types of study and turn them into real steps that people can take to reduce their own risk of cancer."
Earlier this year, US researchers were awarded a patent for a compound called DIM, or diindolylmethane, also found in brassica, and targeted at prostate cancer sufferers. Like the UK research, the US team's findings suggested that DIM-derived compounds had no side effects, targeting simply the cancer cells.
