Archive for the ‘fasting’ Category

by Charles Q. Choi

Instead of eating three square meals a day, an eating schedule that involves “intermittent fasting” could help fight not just obesity but many related diseases of modern life, such as diabetes, heart disease, cancer and Alzheimer’s, researchers say.

he advice given on fighting obesity usually focuses on consuming fewer calories and exercising more. The benefits of such foods as vegetables, fruits, nuts, fiber and fish, and the value of reducing or eliminating snacks are often also touted.

However, mounting evidence reveals that other key aspects of diet — when and how often people eat — can also play a major role in health. In fact, the most common eating pattern in modern societies of three meals daily, plus snacks, is abnormal from the perspective of human evolution, an international group of researchers wrote in an article published in the journal Proceedings of the National Academy of Sciences.

More and more research shows that intermittent fasting could have benefits, they said.

“Fasting alone is more powerful in preventing and reversing some diseases than drugs,” said Satchidananda Panda, an associate professor of regulatory biology at the Salk Institute for Biological Studies in San Diego, California, and one of the co-authors of the article.

Ancient hunter-gatherers often ate only intermittently, the researchers noted in their article. This suggests that the ability to function at a high level both physically and mentally during extended periods without food may have been crucial in human evolution, and that the human body may have adapted to perform at its best with intermittent fasting.

Such intermittent fasting could consist of eating 500 calories or less either two days each week, or every other day, or not eating breakfast and lunch several days each week, the researchers said.

Prior research suggests that in animals, intermittent fasting can fend off or even reverse such illnesses as cancer, diabetes, heart disease and neurodegenerative disorders. Animal studies suggest that intermittent fasting provides these benefits by allowing the body to respond better to stress that might otherwise damage it. For example, fasting could starve tumors, reduce inflammation, or improve the removal of damaged molecules and other components of cells, the researchers said.

“Intermittent fasting helps the body to rejuvenate and repair, thereby promoting overall health,” Panda told Live Science.

In addition, the body may respond better to meals eaten at some times of the day rather than others because of the body’s circadian rhythms. In the years before artificial light, people depended on natural patterns of day and night, with food primarily eaten during the day and fasting occurring at night. This means that eating at certain times of the day may be healthier for the body’s metabolism — for example, in 2013, two studies in humans suggested that eating meals earlier in the day improved weight loss in overweight and obese people.

Panda said that it may be challenging for people to fast intermittently, instead of eating three meals every day. Eating breakfast is often promoted as a weight-control aid, but recent evidence has suggested it might not be, the researchers said.

Future research needs to further explore the benefits and drawbacks of different types of intermittent fasting in a variety of populations. “Its effectiveness in both preventing and reversing diseases, as well as interaction with standard medications for chronic metabolic diseases, should be tested in appropriate volunteer groups,” Panda said.

http://www.livescience.com/48888-intermittent-fasting-benefits-weight-loss.html

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 suggests.

By Sarah Knapton

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 diets have been criticised 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 diseases.

The researchers say fasting “flips a regenerative switch” which prompts stem cells to create brand new white blood cells, essentially regenerating the entire immune system.

“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.

“And the good news is that the body got rid of the parts of the system that might be damaged or old, the inefficient parts, during the fasting.

“Now, 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 stores of glucose and fat but also 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 cell-based regeneration of new immune system cells.

In trials humans were asked to regularly fast for between two and four days over a six-month period.

Scientists found that prolonged fasting also reduced the enzyme PKA, which is linked to ageing and a hormone which increases cancer risk and tumour 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.

“When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of the immune cells that are not needed, especially those that may be damaged,” Dr Longo said.

“What we started noticing in both our human work and animal work is that the white blood cell count goes down with prolonged fasting. Then when you re-feed, the blood cells come back. So we started thinking, well, where does it come from?”

Fasting for 72 hours also protected cancer patients against the toxic impact of chemotherapy.

“While chemotherapy saves lives, it causes significant collateral damage to the immune system. The results of this study suggest that fasting may mitigate some of the harmful effects of chemotherapy,” said co-author Tanya Dorff, assistant professor of clinical medicine at the USC Norris Comprehensive Cancer Center and Hospital.

“More clinical studies are needed, and any such dietary intervention should be undertaken 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 Prof Longo.

However, some British experts were sceptical 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: “There is some interesting data here. It sees that fasting reduces the number and size of cells and then re-feeding at 72 hours saw a rebound.

“That could be potentially useful because that is not such a long time that it would be terribly harmful to someone with cancer.

“But I think the most sensible way forward would be to synthesize this effect with drugs. I am not sure fasting is the best idea. People are better eating on a regular basis.”

Dr Longo added: “There is no evidence at all that fasting would be dangerous while there is strong evidence that it is beneficial.

“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.”

http://www.telegraph.co.uk/news/uknews/10878625/Fasting-for-three-days-can-regenerate-entire-immune-system-study-finds.html