“Recent aging studies have shown that caloric restriction and fasting have a prolonging effect on lifespan in model animals … but the detailed mechanism has remained a mystery,” explains Takayuki Teruya, first author on the new study.
The research set out to analyze the metabolic profile of blood samples as subjects underwent an extensive stretch of fasting. Four healthy participants were recruited and subjected to a long fast, with blood samples taken at three points in the process: 10, 34 and 58 hours after commencing fasting. Unlike prior research, which often focused on specific metabolic biomarkers, this study was non-targeted with a goal of uncovering previously unidentified metabolic effects from fasting. It was found that fasting induced metabolitic activity swiftly. The researchers identified 44 different blood-based metabolites significantly increasing in abundance after 58 hours of fasting, including 30 that have never before been connected to the practice. Alongside known markers signaling the body is moving to utilizing alternative energy stores, such as butyrates and branched-chain amino acids, an interesting increase in anti-oxidant metabolites was found. It is suggested this could be an evolutionary defense against the oxidative stress put on the body during fasting.