Regular fasting protects and rejuvenates the immune system
Researchers at the University of Southern California, working under the guidance of Professor Walter Longo, have demonstrated that periodic fasting not only protects the immune system from damage, which is one of the main side effects of chemotherapy, but also stimulates its rejuvenation due to the transition of stem cells from a state of rest to a state of self-renewal.
During the experiments, mice were repeatedly left without food for periods of 2-4 days for six months. Such starvation causes the body to expend glucose and fat reserves. At the same time, a sufficiently large part of immune cells, especially aged and damaged ones, is also processed. Longo compares this mechanism to getting rid of excess cargo when there is a need to lighten the aircraft.
The decrease in the number of immune cells occurring during each fasting cycle triggers the process of regeneration of the immune system due to the division and differentiation of stem cells. As a result, when the intake of nutrients is resumed, the number of immune cells in the body increases to the previous indicators. One of the mechanisms underlying this phenomenon is the suppression of the activity of the enzyme protein kinase A (PKA). According to the results obtained by Longo in earlier works, this effect increases the lifespan of simple organisms, while other researchers have demonstrated its involvement in the processes of regulating self-renewal and maintaining pluripotency of stem cells. Moreover, fasting reduces the level of insulin-like growth factor-1 (IGF-1), which plays an important role in the aging process, the progression of malignant tumors, as well as in the predisposition to the development of cancer.
Experiments on mice have shown that cyclically repeated periods of fasting reduce the severity of immunosuppression and mortality caused by antitumor chemotherapy, as well as reverse the age-related extinction of the immune system (the lower part of the figure from the article in Cell Stem Cell).
A pilot clinical trial involving patients with malignant tumors also demonstrated that fasting for 72 hours before chemotherapy reduces the toxic effects of drugs.
The researchers believe that their observations will help both in the fight against age-related manifestations of immunodeficiency and with the life-threatening side effects of chemotherapy for cancer patients. Currently, they are studying the effect of cyclic periods of fasting on the functioning of various systems and organs.
Article by Chia-Wei Cheng et al. Prolonged Fasting Reduces IGF-1/PKA to Promote Hematopoietic-Stem-Cell-Based Regeneration and Reverse Immunosuppression is published in the journal Cell Stem Cell.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the University of Southern California:
Fasting triggers stem cell regeneration of damaged, old immune system.
09.06.2014