Can fasting help cancer patients?

Scientists are looking to help patients fight cancer by providing a 'magic shield', either by fasting or by drugs to mimic the effects of fasting.

Fasting for as little as 48 hours protects healthy cells against chemotherapy, according to a study by a team led by Dr Valter Longo at the University of Southern California, which is preparing to test the method on a small group of bladder cancer patients.

Mice given a high dose of chemotherapy after fasting continued to thrive, but the same dose killed half the normally-fed mice and caused lasting weight and energy loss in the survivors, the team reported.

Test tube experiments confirmed normal human cells were two to five times more resistant than cancer cells to chemotherapy after a short period of starvation.

"If we get to just a 10-20 fold differential toxicity with human metastatic (spreading) cancers, all of a sudden it's a completely different game against cancer," Dr Longo said.

"My hope is that many places around the world will carefully design small clinical trials on starvation and protection against chemotherapy," he said, adding that the effects of starvation can also be mimicked by a drug and this approach will also be tested.

The team stressed that fasting was not the same as malnourishment, when inadequate nutrients are taken in and can easily be tolerated given progress in cancer care.