Fasting May Improve Cancer Chemotherapy
Temporary Fast Shields Healthy Cells, While Chemo Drugs Target Cancerous Cells, Study Shows
By
Jennifer Warner
WebMD Medical News
Reviewed by
Louise Chang, MD
Fasting prior to cancer chemotherapy treatment may significantly enhance the cancer-killing effects of the drugswhile protecting healthy cells from damage.
A
new study suggests starvation induces a protective shield around
healthy cells, allowing them to tolerate a much higher dose of
chemotherapy.
The results showed starving laboratory mice for two days prior to
chemotherapy treatment protected them from potentially toxic high doses
of the drug, and they gained back the weight they lost after treatment.
Researchers
say cancer chemotherapy can kill as many healthy cells as cancerous
ones, but inducing temporary starvation increases the cells' resistance
to stress, which may allow doctors to use higher doses of current cancer chemotherapy treatments to make them more effective.
Chemotherapy Starvation Diet
In the study, published in the Proceedings of the National Academy of Sciences, researchers studied the effects of starvation on cancerous and normal cells.
First,
they induced a starvation-related response in yeast cells, which made
them 1,000 times more protected than untreated cells.
Then,
they tested the effects of fasting on human and cancer cells in a test
tube and in mice. The results showed starvation produced between a
twofold and fivefold difference in stress resistance between the
normal, starvation-treated cells and normal cells. In tests with live
mice, of 28 mice starved for 48-60 hours before chemotherapy, only 1
died. Of 37 mice that were not starved prior to treatment, 20 mice died
from chemotherapy toxicity.
"More importantly, we
consistently showed that mice were highly protected while cancer cells
remained sensitive," researcher Valter Longo, PhD, of the University of
Southern California, says in news release. "If we get to just a 10- to
20-fold differential toxicity with human metastatic cancers, all of a
sudden it's a completely different game against cancer."
Researchers
say genetic cues prompt starved healthy cells to go into a
hibernation-like mode that produces extreme resistance to stress. But
cancerous cells don't obey those cues and remain stuck in growth mode.
By
using the starvation response to differentiate normal and cancerous
cells, researchers say healthy cells may be able to withstand higher
doses of existing cancer chemotherapy drugs, but further studies in
humans are needed to confirm these effects.