Study in mice suggests that caloric restriction (CR) promotes metabolic switch and protects against intestinal diseases, such as infections and cancers

Fasting a whole day can bring great benefits to intestinal health. This is demonstrated by a study conducted by the Biology department of MIT, published on the Scientific Journal Cell Stem Cell. According to the study carried out in mice, a 24-hour fast provides metabolic switch and augments intestinal stem cell function.

“Fasting has many effects in the intestine, which include boosting regeneration as well as potential uses in any type of illness that invades on the intestine, such as infections or cancers”, says one of the Biologists and author of this study, Omer Yilmaz, to MIT News.

The process can renew the lining of the intestine before the five days that are usually taken for mice on a regular diet.

The biological key that binds the ignition of accelerated stem cell regeneration is called fatty acid oxidation. “This study provides evidence that fasting induces a metabolic switch in the intestinal stem cells, from utilizing carbohydrates to burning fat [as the first source of energy],” David Sabatini, another author of the study, explains.

Fasting changes energy source and improves stem cell function

The study which tested fasting in mice of all ages resulted in was similar outcomes in each age group. This demonstrates that the process also works as a way to curb cellular aging.

The metabolic switch of the primary energy source, utilizing carbohydrates (glucose, to be more precise) to burn fat, enables a much quicker renewal of stem cells. Which boosts the formation of more efficient organoids. Fasting not only renews the intestinal lining but also improves its performance.

To understand how this molecular process occurs, MIT scientists sequenced the messenger RNA from the stem cells of the mice in caloric restriction and found out the secret: fasting activates receptors, known by the acronym PPAR, which the genes are responsible in the metabolism of fatty acids. This mechanism induces cells to feed on fatty acids instead of glucose.

“Activating just one metabolic pathway is sufficient to reverse certain age phenotypes. This work fits into a rapidly growing field that is demonstrating that nutrition and metabolism have profound effects on the behavior of cells and this can predispose for human disease”, said Jared Rutter to MIT News, a Professor from The University of Utah School of Medicine, who was not involved in the research.

Low calorie consumption makes you live longer and healthier

It’s been a while since scientific studies have identified the benefits of fasting or low-calorie strategies (provided there is no trace of malnutrition).

The most famous case is from the work of Japanese scientist Yoshinori Ohsumi, who was honored with The Nobel Prize in Medicine 2016 due to his study dedicated to understanding the mechanisms of autophagy, a self-cleaning process performed by all cells of our body. In this study, the cell feeds on its weaker internal parts and eliminates them. Ohsumi found that autophagy is activated when the cell is subjected to stressful situations, such as intermittent fasting.

Another notable set of work on this issue was published on Nature Communications in 2017. This study shows findings about two studies that monitored rhesus monkeys for over 25 years – the rhesus monkey genome is more similar to the human genome. After the papers presented inconclusive results on the effects of fasting, a final paper demonstrated that yes, “calorie restriction increases life expectancy and delays the onset of age-related disorders.” That is, monkeys live longer and healthier.

“These data confirm that health benefits of CR are conserved in monkeys and suggest that CR mechanisms are likely translatable to human health,” the article concludes.

Content published in May 24, 2018

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