Fasting has a myriad of benefits, and now, a team of researchers has claimed that it can even reprogramme the metabolism of natural killer cells, helping them to survive in the harsh environment in and around tumors while also improving their cancer-fighting ability
The new study in mice from researchers at Memorial Sloan Kettering Cancer Center (MSK) in New York revealed that fasting may help the body defend against cancer, starving cancer cells of the nutrients they need to grow.
“Tumours are very hungry. They take up essential nutrients, creating a hostile environment often rich in lipids that are detrimental to most immune cells,” according to immunologist Joseph Sun, the study’s senior author.
Fasting reprogrammes these natural killer cells (a type of white blood cell) to better survive in this suppressive environment, he said in a paper published in the journal Immunity.
For the study, mice with cancer were denied food for 24 hours twice a week, and then allowed to eat freely in between fasts.
Just like humans, the mice saw a drop in their glucose levels and a rise in free fatty acids, which are lipids released by fat cells that can serve as an alternative energy source when other nutrients are not present, according to Rebecca Delconte, lead author of the study.
During each of these fasting cycles, natural killer cells learned to use these fatty acids as an alternative fuel source to glucose.
This optimized their anti-cancer response because the tumor microenvironment contains a high concentration of lipids, and now they were able to enter the tumor and survive better because of this metabolic training, the authors noted.
While more research is needed, the results suggest fasting could be a strategy to improve immune responses to make immunotherapy more effective.
