UNITED KINGDOM, 05 June, 2014 (by Sarah Knapton, The Telegraph): A person's entire immune system can be rejuvenated by fasting for as little as three days as it triggers the body to start producing new white blood cells, a study suggest. Researchers say fasting "flips a regenerative switch" which prompts stem cells to create brand new white blood cells.Although fasting diets have been criticized by nutritionists for being unhealthy, new research suggests starving the body kick-starts stem cells into producing new white blood cells, which fight off infection. Scientists at the University of Southern California say the discovery could be particularly beneficial for people suffering from damaged immune systems, such as cancer patients on chemotherapy. It could also help the elderly whose immune system becomes less effective as they age, making it harder for them to fight off even common disease. "It gives the 'OK' for stem cells to go ahead and begin proliferating and rebuild the entire system," said Prof Valter Longo, Professor of Gerontology and the Biological Sciences at the University of California.
Prolonged fasting forces the body to use stores of glucose and fat but also breaks down a significant portion of white blood cells. Scientists found that prolonged fasting also reduced the enzyme PKA, which is linked to aging and a hormone which increases cancer risk and tumor growth. "We could not predict that prolonged fasting would have such a remarkable effect in promoting stem cell-based regeneration of the hematopoietic system," added Prof Longo. However, some British experts were skeptical of the research. Dr Graham Rook, emeritus professor of immunology at University College London, said the study sounded "improbable."
Chris Mason, Professor of Regenerative Medicine at UCL, said: "I have received emails from hundreds of cancer patients who have combined chemo with fasting, many with the assistance of the oncologists. Thus far the great majority have reported doing very well and only a few have reported some side effects including fainting and a temporary increase in liver markers. Clearly we need to finish the clinical trials, but it looks very promising."