The study shows that fasting accelerates human metabolism

Fasting can help people lose weight, but new research suggests that the lack of food could also boost human metabolic activity, generate antioxidants, and help reverse some of the effects of the body. aging. Scientists at the University of the Okinawa Institute of Science and Technology (OIST) and Kyoto University have identified 30 previously undeclared substances, which increase during fasting and indicate various benefits for health.

"We have been studying aging and metabolism for many years and have decided to look for unknown health effects during human fasting," said Dr. Takayuki Teruya, the first author of the article and technician at the University of New York. OIST G0 cell unit, led by Professor Mitsuhiro. Yanagida. "Contrary to initial expectations, it turned out that fasting induced a rather active metabolic activation."

The study, published on 29 January 2019 in Scientific reports, presents an badysis of total human blood, plasma and red blood cells taken from four fasted individuals. The researchers monitored the changing rates of metabolites, substances formed during chemical processes that give energy to organisms and allow them to grow. The results revealed that 44 metabolites, 30 previously unknown, increased universally in subjects 1.5 to 60 times in just 58 hours after fasting.

In previous research, the G0 cell unit has identified various metabolites whose amounts decrease with age, including three leucine, isoleucine and ophthalmic acid. In fasted individuals, the level of these metabolites increases, suggesting a mechanism by which fasting may help increase longevity.

"These are very important metabolites for maintaining muscle and antioxidant activity, respectively," said Teruya. "This result suggests the possibility of a rejuvenating effect by fasting, which was not known until now."

Metabolites give clues to mechanism and health effects

The human body tends to use carbohydrates to produce energy quickly, when they are available. When the body runs out of carbohydrates, the body begins to loot its alternative energy reserves. The act of "energy substitution" leaves a trace, including metabolites called butyrates, carnitines and branched chain amino acids. These well-known markers of energy substitution have been shown to accumulate during fasting.

But fasting seems to produce effects far beyond the substitution of energy. In their comprehensive badysis of human blood, researchers noted both established fast markers and many others. For example, they found an overall increase in substances produced by the citric acid cycle, a process by which organisms release energy stored in the chemical bonds of carbohydrates, proteins and lipids. The marked increase suggests that during fasting, the tiny central cells of all cells are submerged.

Fasting also appears to improve the metabolism of purine and pyrimidine, chemicals that play a key role in gene expression and protein synthesis. The discovery suggests that fasting can reprogram which proteins the cells build at what time, thus altering their function. The change can promote homeostasis in cells or serve to alter the expression of their genes in response to environmental influences.

When they are metabolized, purine and pyrimidine also stimulate the production of antioxidants by the body. It was found that several antioxidants, such as ergothioneine and carnosine, increased significantly over the 58-hour study period. Antioxidants are used to protect cells from free radicals produced during metabolism. The products of a metabolic pathway called "pentose phosphate pathway" also remain the harmful effects of oxidation and have also been seen to increase during fasting, but only in plasma.

New health benefits of fasting?

The authors suggest that these antioxidant effects could be the main response of the body to fasting, as starvation can promote a dangerously oxidative internal environment. Their exploratory study provides the first evidence of antioxidants as a fasting marker. In addition, the study introduces the new notion that fasting may stimulate the production of several age-related metabolites, abundant in the young but exhausted in the older age groups.

"Recent studies on aging have shown that calorie restriction and fasting have a prolonged effect on the lifespan of model animals … but the detailed mechanism remains a mystery," said Teruya. "It might be possible to check the anti-aging effect from different points of view by developing exercise programs or drugs that can cause the metabolic reaction in the same way as fasting."

The results develop well-established ideas about what fasting could do for human health. The next step would be to replicate these results in a larger study or to examine how metabolic changes might be triggered by other means.

"People want to know if humans can benefit from the effects of preventing metabolic diseases and prolonging their lives by fasting or caloric restriction, as in model animals," said Teruya. "Understanding the metabolic changes caused by fasting should give us the wisdom to maintain health."

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University graduated from the Institute of Science and Technology of Okinawa