In Focus

05 December 2008 03:52 BST

Diet and cancer

Miracle 'food cancer cures' often hit the headlines, but can what you eat actually affect your risk of cancer or help to beat the disease?

The latest story to emerge is that of 79-year-old Ray Wiseman, who claimed that his daily intake of broccoli helped to beat his bladder cancer.

Five-and-a-half-years ago he was diagnosed with the disease and doctors did not expect him to live. But now the cancer has been halted in its tracks and he believes it is due to the daily tumbler of juiced broccoli he drank.

The vegetable is not the only one to be linked to cancer.

inthenews.co.uk takes a look at what other foods are linked both positively and negatively with cancer risk and how seriously the claims should be taken.

What foods are believed to cut cancer risk?

Numerous studies have found benefits of a Mediterranean-style diet and in July 2008 researchers at Harvard University found that the more closely this diet is followed, the lower the risk of developing cancer. The diet is rich in fruit, vegetables, whole grains and fish and has little processed foods, refined sugars and cured and red meats.

In 2006 scientists at the Karolinska Institute in Sweden claimed that eating fatty fish such as salmon a few times a month could reduce the risk of kidney cancer after studying more than 90,000 women.

A number of studies have also linked tea and green tea to a lower cancer risk. In April 2005 Italian researchers from the University of Parma and University of Modena and Reggio Emilia found that green tea reduced the risk of prostate cancer in a group of 32 men at high risk of the disease.

And researchers at the University of Southern California claimed in 2002 that substances in tea could help to reduce the risk of stomach and oesophagus cancer.

Over the past decade research has linked broccoli to lower risks of prostate cancer and in July a research group at the Institute of Food of Research said that eating one or more portions of broccoli every week can reduce the risk of prostate cancer by changing cell signalling pathways.

What foods have been linked to increased cancer risk?

In October a report from the World Cancer Research Fund warned that processed meats, including ham and bacon, increase the risk of colorectal cancer and advised that people who eat them do so sparingly (no more than 500g a week).

The WCRF study was carried out by 21 world-renowned scientists who analysed 7,000 studies from around the world on cancer and lifestyle choices.

Alcohol consumption is recommended by the WCRF to be no more than two drinks a day for men and one for women.

In March last year researchers at the National Cancer Institute linked high-fat diets to an increased risk of breast cancer.

And in October 2007 scientists based at the Dana-Farber Cancer Institute warned that colon cancer patients who eat a diet high in red meat, fatty products and refined grains could increase their chance of disease relapse.

What do the experts say?

Cancer Research UK advises that no one 'superfood' can be eaten to reduce cancer risk and that to maintain general health people should eat a healthy, balanced diet.

According to the charity about a quarter of all cancer deaths are caused by unhealthy diets and obesity. It advises that cancer risk can be reduced by eating a healthy, balanced diet that is high in fibre, fruit and vegetables, and low in red and processed meat and saturated fat.

Commenting on the case of Mr Wiseman and his broccoli juice, Dr Kat Arney, senior science information officer at Cancer Research UK said: "Our understanding of how diet may affect cancer risk is rapidly growing but it is still incomplete.

"Broccoli has had a lot of research focussed on it due to some of the chemicals in the vegetable. While this is important research, there is no scientific evidence to prove that any one 'super' fruit or vegetable can prevent or cure cancer. So, our best advice is to eat a healthy balanced diet that is high in all types of fruit and vegetables."


Carolyn Robertson