Rhubarb contains natural chemicals called polyphenols that have been shown to kill cancer cells in the lab, or prevent their growth. Baking appears to greatly increase the levels of these chemicals, UK scientists have found, but Cancer Research UK cautioned against reading too much into these results.
Commenting on the research, Ed Yong, Cancer Research UK's head of health information, said: "Certain methods of cooking rhubarb may increase levels of polyphenols in lab tests, but it's a big leap to say that this will have a noticeable impact on the risk of cancer in real people.
"Rather than relying on a single food, our advice is to enjoy rhubarb as part of a varied diet high in fibre, fruit and vegetables and low in red and processed meat, saturated fat and salt."
A team at Sheffield Hallam University found that British garden rhubarb (Rheum rhapontigen) contains various polyphenols, as they revealed in the journal Food Chemistry.
Baking rhubarb for 20 minutes before eating led to a significant increase in the levels of these chemicals with anti-cancer properties, although excessive cooking can cause these compounds to be broken down.
It is hoped that scientists can now work out the combination of rhubarb compounds and chemotherapy drugs that is most effective at killing leukaemia cells.
Dr Nikki Jordan-Mahy, from Sheffield Hallam University's Biomedical Research Centre, said: "Our research has shown that British rhubarb is a potential source of pharmacological agents that may be used to develop new anti-cancerous drugs."
Ed Yong said: "We'll need more studies to see if the chemicals in rhubarb have anti-cancer properties that could ultimately be harnessed to develop drugs. Several successful cancer treatments have been derived from plants, but a great deal of work is needed to turn a naturally occurring chemical into an effective and potent drug."
How different types of bread impact cancer risk