Intermittent Fasting May Help Immune System's Natural Killer Cells Fight Back Against Cancer

Intermittent fasting has been linked with improved brain function, heart health, and weight loss. What can it do for cancer? Research has been looking into how it may help starve out cancer cells by depriving them of the nutrients they need to grow, but a new study says it may also help reprogram the immune system to better fight tumors and survive in environments where they exist.

Research recently published in the journal Immunity looked at how intermittent fasting impacted natural killer (NK) cells and their ability to fight tumors. NK cells help limit the spread of cancer and infections by targeting harmful cells. Unlike T cells, they can recognize a threat before being exposed to it.

To see how fasting impacted these cells, a team of researchers from Memorial Sloan Kettering Cancer Center deprived mice of food for two 24-hour periods each week and let them eat freely the rest of the time. While they fasted, the mice had the same response as humans typically do: lower levels of glucose and higher levels of lipids, or fatty acids. During this time, NK cells in the spleen learned to consume lipids rather than glucose. This helped them survive in the tumor environment.

Dr. Joseph Sun, senior author and immunologist, explains, “Tumors are very hungry. They take up essential nutrients, creating a hostile environment often rich in lipids that are detrimental to most immune cells. What we show here is that fasting reprograms these natural killer cells to better survive in this suppressive environment.”

In other parts of the body, NK cells went from peripheral tissues to bone marrow, which exposed them to higher levels of a signaling protein called Interleukin-12. This helped them produce a cytokine that helps with their anti-tumor response. It’s currently unclear if the same cells learned both behaviors, or if they were different groups altogether.

While the team says more research is needed into how intermittent fasting can impact human cancer patients, blood tests have shown that fasting redistributed NK cells in a similar way. This provides hope that fasting may one day help improve immunotherapy.

Going forward, the researchers say the topic can be studied further by determining whether fasting is safe for cancer patients or if there may be a way to promote these NK cell reactions without fasting.

You can read the whole study here.