Fasting may improve health and shield against age-related diseases, study finds

17 Jan 2019 --- Fasting intermittently (IF) may reprogram a variety of cellular responses and result in a range of health benefits, according to a US study conducted on mice. Fasting was found to affect circadian clocks in the liver and skeletal muscles, causing them to rewire their metabolism, which may promote health and protect from age-related diseases. The research, published in Cell Reports, opens new pathways of investigation that may lead to the development of nutritional strategies to improve health in humans.

Diets that incorporate fasting are increasingly being touted by proponents as improving blood sugar levels, decreasing the risk of heart disease, stroke and cancer and preventing or delaying the onset of neurodegenerative diseases.

The body’s circadian clock helps us maintain homeostasis in response to the changing environment. Food is known to influence a person’s circadian clock in peripheral tissues, but until now it was unclear in how a lack of food influences clock function and ultimately bodily functions.

“We discovered [that] fasting influences the circadian clock and fasting-driven cellular responses, which together work to achieve fasting-specific temporal gene regulation,” says the study’s lead author Paolo Sassone-Corsi, Professor of Biological Chemistry at University of California's School of Medicine. 

The researchers subjected mice to 24 hour fasting periods. They found that the test subjects exhibited a reduction in oxygen consumption (VO2), respiratory exchange ratio (RER) and energy expenditure. All of the aforementioned effects disappeared once the mice were fed again. The experiment mirrors results observed in human trials. 

“The reorganization of gene regulation by fasting could prime the genome to a more permissive state to anticipate upcoming food intake and thereby drive a new rhythmic cycle of gene expression. In other words, fasting is able to essentially reprogram a variety of cellular responses,” notes Sassoni-Corsi.

“Therefore, optimal fasting in a timed manner would be strategic to positively affect cellular functions and ultimately benefiting health and protecting against aging-associated diseases,” he adds. 

Intermittent fasting is becoming increasingly popular and there are numerous variations of fasting diets that claim different health benefits. For example, the 5:2 diet (normal consumption five days a week and restricted calories two days a week), the warrior diet (eating small amounts of raw fruits and vegetables during the day and one large meal at night) and the CSIRO “Flexi” diet.

“Intermittent Fasting is an umbrella term encompassing a range of diets where the pattern of calorie restriction and/or timing of food intake are altered so that the individuals undergo frequently repeated periods of fasting,” says Dr. Samefko Ludidi, Food and Health consultant, and researcher at Maastricht University. 

Emerging research on the benefits of fasting includes a recent University of Adelaide study saying that obese women following a strictly controlled diet and IF lose the most weight and enjoy improvements in their overall health when compared to several other diets. The study, published in the journal Obesity, involved a sample of 88 women following carefully controlled diets for over ten weeks. The researchers note that further research is warranted to see if these short-term results translate into the long-term.

“In our two-month study, we observed greater improvements in cardiovascular and diabetes risk markers following IF vs. a daily caloric restriction diet (CR) that was prescribed at matched energy restriction,” co-author, Professor Leonie Heilbronn, Ph.D. from the University of Adelaide, tells NutritionInsight.