Fasting could make a whole new healthy you
Three foodless days and you’ll have a brand-new immune system, Sarah Knapton learns
FASTING for as little as three days can regenerate the entire immune system, even in the elderly, scientists have found in a breakthrough described as “remarkable”.
Although fasting has been criticised by some nutritionists as unhealthy, new research suggests that starving the body kick-starts it into producing white blood cells, which fight 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 diseases.
The researchers say fasting “flips a regenerative switch” that prompts stem cells to create brand-new white blood cells, essentially regenerating the entire immune system.
“And the good news is,” said Valter Longo, professor of gerontology and the biological sciences at the University of California, “that the body gets rid of the parts of the system that might be damaged or old — the inefficient parts — during the fasting. If you start with a system heavily damaged by chemotherapy or ageing, fasting cycles can generate, literally, a new immune system.”
Prolonged fasting forces the body to use its stores of glucose and fat fuel and breaks down a significant portion of white blood cells.
During each cycle of fasting, this depletion of white blood cells induces changes that trigger stem cells into regenerating immune system cells.
In trials, people were asked to fast regularly for between two and four days over a six-month period. Scientists found that prolonged fasting also reduced the production of the enzyme PKA, which is linked to ageing, and of a hormone that increases cancer risk and tumour growth.
“We could not predict that prolonged fasting would have such a remarkable effect in promoting stem-cell-based re- generation,” said Longo.
“When you starve, the system tries to save energy, and one of the things it can do to save energy is recycle a lot of the immune cells that are not needed, especially those that might be damaged.
“What we started noticing, in both our human and animal work, is that the white blood cell count goes down with prolonged fasting. Then, when you refeed, the blood cells come back. So we started thinking, well, where do they come from?”
Fasting for 72 hours was found to protect cancer patients from
Fasting might mitigate harmful effects of chemotherapy
the toxic effects inherent in chemotherapy.
Although chemotherapy saves lives, it causes significant collateral damage to the immune system,” said the coauthor of the report on the study, Tanya Dorff, assistant professor of clinical medicine at the University of Southern California’s Norris Comprehensive Cancer Centre and Hospital. “The results of this study suggest that fasting might mitigate some of the harmful effects of chemotherapy.”
“More clinical studies are needed, and any such dietary intervention should be under- taken only under the guidance of a physician.
“We are investigating the possibility that these effects are applicable to many different systems and organs, not just the immune system,” added Longo.
Some British experts were sceptical about the research.
Dr Graham Rook, emeritus professor of immunology at University College London, said the findings derived from the study sounded “improbable”.
Chris Mason, professor of regenerative medicine at the University of Southern California, said fasting for 72 hours would “not be terribly harmful” to someone with cancer.
“But I think the most sensible way forward would be to synthesise this effect with drugs. I am not sure fasting is the best idea. People are better off eating regularly.”
Longo added: “There is no evidence that fasting would be dangerous, but there is strong evidence that it is beneficial.
“I have received e-mails from hundreds of cancer patients who have combined chemotherapy with fasting, many with the assistance of the oncologist. 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.”—