Study Shows Fasting Enhances Natural Killer Cells’ Cancer-Fighting Abilities in Mice
Periods of fasting can reprogram natural killer cells in the immune system to better combat cancer, as demonstrated in a recent study involving mice by researchers at Memorial Sloan Kettering Cancer Center (MSK).
Fasting and other dietary approaches are increasingly studied for their potential to deprive cancer cells of essential nutrients and enhance the efficacy of cancer treatments. The research team, led by postdoctoral fellow Dr. Rebecca Delconte, published their findings in Immunity on June 14. They discovered that fasting alters the metabolism of natural killer cells, enabling them to survive and function more effectively in the challenging environment around tumors.
The study suggests that fasting not only aids in reducing fat and improving metabolism but also enhances immune responses, potentially making immunotherapy more successful. According to senior author Dr. Joseph Sun, fasting helps natural killer cells adapt to the nutrient-deprived conditions created by tumors, optimizing their ability to target and destroy cancer cells.
Natural killer cells, known as NK cells, are a type of white blood cell capable of attacking cancerous or infected cells without prior exposure. The study involved fasting mice with cancer for 24 hours twice weekly, maintaining their weight by allowing them to eat freely between fasts.
During fasting periods, the mice showed decreased glucose levels and increased levels of free fatty acids, which NK cells adapted to use as an alternative energy source. This metabolic shift improved their ability to enter tumors and survive within them, enhancing their anti-cancer properties.
Furthermore, fasting led to a redistribution of NK cells within the body, with cells in the bone marrow exposed to higher levels of Interleukin-12, a key signaling protein that primes them to produce more Interferon-gamma. This cytokine plays a crucial role in anti-tumor immune responses.
While the study focused on mice, the researchers noted similar observations in human blood samples from cancer patients undergoing fasting. They emphasized the need for further research to validate these findings in clinical settings and explore potential therapeutic applications, including combining fasting with existing cancer treatments or developing drugs that mimic fasting effects on immune cells.
Dr. Neil Iyengar, an MSK breast medical oncologist not involved in the study, highlighted the importance of personalized medical advice for patients considering fasting, cautioning that different fasting regimens may have varying effects on health and treatment outcomes.
