Professor Robert Thomas warned the supplements could actually make them more susceptible to cancer.

The specialist, from Cambridge University Hospitals, said taking brisk walks and becoming slimmer could reduce the side-effects of treatment and increase the likelihood of beating the disease.


He said ‘the elephant in the room’ during discussions about the cost of expensive new drugs was the effort patients could make themselves.

Only one in ten cancer patients take any exercise at all during recovery from treatment. Some feared making their fatigue worse, and were not aware of the benefits, he said, while others ignored health advice.

He added: ‘Many people think that instead of going to the gym, they can grab a whole load of supplements and that will do the job.

‘But there is no evidence for the majority of these supplements that they have any benefit.

‘There is a role for some supplements, alongside a healthy diet, but patients are receiving no guidance.
They mainly take mineral and vitamin supplements, many of which have no evidence of benefit – but more worryingly, if taken long term, could increase the risk of cancer.’

Research shows that healthy lifestyles give cancer patients a better chance of coping with gruelling treatment, as well as fewer side-effects.

Professor Thomas said: ‘There is a lot of focus on drugs that extend lives by months but not enough on what people can do to help themselves.

‘Three hours of exercise per week after most cancers will reduce the chance of relapse by up to 30 per cent.
Yet little time is spent discussing lifestyle issues compared to extensive deliberations about chemotherapy, which in some cases only offers a 5 per cent benefit.’

In a study of 120 patients, he found only 11 per cent were exercising during recovery, while 68 per cent were overweight or obese.

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