Can fasting reduce chemotherapy's side effects?

Mice starved for 48-60 hours and then given high doses of a chemotherapy drug showed no visible signs of toxicity in a new study, while many control animals died from the treatment. When the animals were injected with neuroblastoma cells, the fasting combined with chemotherapy didn't appear to blunt the treatment's effects on the cancer, suggesting that healthy cells were protected from chemotherapy but cancer cells were not.

The researchers believe that cutting calories slows the growth rate of cells, making them more stress resistant and more resistant to any type of toxin. However, in cancer cells, oncogenes regulate stress resistance, and those genes are always on, causing the cells to produce growth factors unaffected by calorie restriction. The short-term starvation protected healthy cells in mice, but not injected neuroblastoma cells, against a high dose of the chemotherapy drug etoposide.

The study suggests that a starvation-based differential stress-resistant strategy might increase the efficacy of chemotherapy and that specific agents that promote oxidative stress and DNA damage could have the potential to maximize the differential toxicity to normal and cancer cells. A clinical trial, in which patients undergoing treatment for bladder and lung cancer will fast for as long as three days with only water to drink, is planned to begin soon.

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Raffaghello, L., Lee, C., Safdie, F.M., Wei, M., Madia, F., Bianchi, G., et al. (2008). Starvation-dependent differential stress resistance protects normal but not cancer cells against high dose chemotherapy. Proceedings of the National Academcy of Sciences of the United States of America, 105(24), 8215-8220.