Fasting for two days protects healthy cells against chemotherapy, according to a study appearing online the week of March 31 in PNAS Early Edition. Test tube experiments with human cells confirmed the differential resistance of normal and cancer cells to chemotherapy after a short period of starvation.
Mice given a high dose of chemotherapy after fasting continued to thrive. The same dose killed half the normally fed mice and caused lasting weight and energy loss in the survivors.
The chemotherapy worked as intended on cancer, extending the lifespan of mice injected with aggressive human tumors, reported a group led by Valter Longo of the USC Davis School of Gerontology and USC College.
Making chemotherapy more selective has been a top cancer research goal for decades. Oncologists could control cancers much better, and even cure some, if chemotherapy was not so toxic to the rest of the body.
Experts described the study as one of a kind.
“This is a very important paper. It defines a novel concept in cancer biology,” said cancer researcher Pinchas Cohen, professor and chief of pediatric endocrinology at UCLA. “In theory, it opens up new treatment approaches that will allow higher doses of chemotherapy. It’s a direction that’s worth pursuing in clinical trials in humans.”
Fasting before chemotherapy has unknown risks and benefits for humans, Longo cautioned. Only clinical trials can establish the effectiveness and safety of fasting before chemotherapy.
“Don’t try and do this at home. We need to do the studies,” said Quinn, the USC Norris oncologist.
Source: University of Southern California, USA