New research from California scientists has revealed a surprising effect of prolonged fasting.
In a study published in Cell Stem Cell, researchers at the University of Southern California showed that fasting prompts the immune system to flush out old, damaged cells and replace them with new ones. This is the first direct evidence of such an effect and has major implications for age‑related immune decline and chemotherapy‑related immune damage.
Scientists have discovered how cycles of prolonged fasting can help flush out damaged immune cells.
In lab experiments—first in animals, then in a Phase 1 clinical trial—the team found that two‑ to four‑day fasting cycles prompted the immune system to clear immune cells. Surprisingly, the fasts also activated dormant stem cells, prompting them to produce new immune cells.
The findings made sense once the team looked deeper. As corresponding author Valter Longo explained:
“When you starve, the system tries to save energy, and one way it does that is by recycling immune cells that aren’t needed—especially those that may be damaged. In both our human and animal studies, white blood cell counts fell during prolonged fasting and returned after refeeding. We asked: where do the new cells come from?”
Scientists have long known that fasting forces the body to use stored glucose and fat and break down white blood cells. Longo’s team traced the process and found that prolonged fasting lowers levels of an enzyme called PKA. Earlier work linked reduced PKA with increased longevity in simple organisms, and other groups connected PKA to stem cell self‑renewal.
“PKA is the key gene that must shut down for stem cells to enter regenerative mode,” Longo said. “And fasting clears out the parts of the immune system that may be old or damaged. If you start with a heavily damaged system, fasting cycles can generate, literally, a new immune system.”
These findings are especially relevant to chemotherapy, which often damages the immune system. Longo’s team hypothesized that fasting might help patients regenerate immune cells more quickly.
To test this, they launched a Phase 1 clinical trial in which chemotherapy patients fasted for 72 hours. Fasting appeared to protect against some toxic effects of treatment.
Next, the team will continue testing in animal models and future trials. They believe the impact may extend well beyond chemotherapy.
“We are investigating whether these effects apply to many systems and organs, not just the immune system,” Longo said.
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Nice post. I learn something totally new and challenging on websites I stumbleupon every day.
It will always be interesting to read through content from other writers and practice
something from other websites.
Please reference the related scientific publications. I would like to know the details. My immune system could definitely benefit from renewal.
when fasting to build your immune system, what is meant by fasting or starvation. Does it mean not eating anything or reducing your caloric by over 75%.
when this article was published i was being hospitalized for passing out in the street during a nearly 100 day fast. the hospital staff were all very decent and understanding and fed me quite well. so, long story short, fasting is good , spiritual and beneficial. but it can be very dangerous so please be careful if you try.