February 15, 2007

watercress and cancer

The Science Media Centre asked a leading cancer expert to comment on recent evidence that watercress might be protective against cancer.

Karol Sikora, Medical Director of Cancer Partners UK, and Professor of Cancer Medicine, Imperial College, said:

“The real problem is that its not watercress specific – there’s nothing magic there. The press release from what is essentially a marketing association is grossly overstated. We know that fruits and vegetables all do affect DNA damage hence the five a day strategy to prevent cancer. There is absolutely nothing special about watercress. I don’t think people will seriously convert to eating 85gm of the stuff each day. That’s an awful lot of cress! You might even turn green. Much better to look holistically at your diet and ensure thats there’s plenty of fruit and vegetables, fibre and as little fat as possible. The other weakness in the study is that it obviously doesn’t actually show a reduction in cancer incidence – its only a long term surrogate that’s changed. Its a problem that always bedevils the science of interventional epidemiology. Such a study would take 20 years – by which time the investigators and their subjects would be rather bored!”