Fruit and veg offer 'limited protection' against cancer

Recent research found eating "five-a-day" has little impact on cancer

There is no evidence a healthy diet can prevent people developing cancer, a Nobel-winning scientist has warned.

Sir Tim Hunt said eating healthy foods could only provide a modest reduction in the risk of developing the disease.

He said the two "most terrible" cancer-causing poisons in the environment were air and water.

The scientist made his comments in a keynote address at the Association for International Cancer Research (AICR) conference in Fife.

Sir Tim, a principal scientist with Cancer Research UK, said there was no evidence from studies that diet could prevent cancer.

He agreed with recent research which found eating the recommended "five-a-day" will only provide limited protection in preventing the disease.

It is manifestly clear we can't apply the knowledge we have to curing cancer because people are still dying from it Sir Tim Hunt

He pointed out anything which damages chromosomes or attacks DNA can cause cancer.

"The two most terrible poisons in the environment causing cancer are air and water," he said.

"If you stopped breathing, you wouldn't get cancer, but you have to breathe to stay alive.

"It is the air itself, not any pollutants in it, and water which are constantly attacking our DNA."

The old adage of "a little of what you fancy" should not be discounted, he suggested.

Rare disease

But he warned that prevention is better than cure when it comes to the health risks associated with tobacco use.

"Lung cancer was a very rare disease before people started smoking," he said.

In the lecture entitled The Truth About Cancer, Sir Tim also stated there are still "very basic things" which are not understood about cancer.

He said: "There is a marked difference in applying knowledge you already have to obtaining new knowledge.

"It is manifestly clear we can't apply the knowledge we have to curing cancer because people are still dying from it."

About 200 researchers from 28 different countries are attending the AICR's 30th anniversary conference in St Andrews this week.