Reduced caloric intake and periodic fasting independently contribute to metabolic effects of caloric restriction. Issue 4 (11th March 2020)

• Record Type: Journal Article
• Authors: Velingkaar, Nikkhil; Mezhnina, Volha; Poe, Allan; Makwana, Kuldeep; Tulsian, Richa; Kondratov, Roman V.
• Is Part Of: Aging cell. Volume 19:Issue 4(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-11
• Subjects: caloric restriction -- circadian rhythms -- fasting -- gene expression -- glucose homeostasis -- insulin sensitivity -- longevity -- metabolism; Cells -- Aging -- Periodicals; 571.8783605
• DOI: 10.1111/acel.13138
• Languages: English
• ISSNs: 1474-9718

Abstract

Abstract: Caloric restriction (CR) has positive effects on health and longevity. CR in mammals implements time‐restricted (TR) feeding, a short period of feeding followed by prolonged fasting. Periodic fasting, in the form of TR or mealtime, improves metabolism without reduction in caloric intake. In order to understand the relative contribution of reduced food intake and periodic fasting to the health benefits of CR, we compared physiological and metabolic changes induced by CR and TR (without reduced food intake) in mice. CR significantly reduced blood glucose and insulin around the clock, improved glucose tolerance, and increased insulin sensitivity (IS). TR reduced blood insulin and increased insulin sensitivity, but in contrast to CR, TR did not improve glucose homeostasis. Liver expression of circadian clock genes was affected by both diets while the mRNA expression of glucose metabolism genes was significantly induced by CR, and not by TR, which is in agreement with the minor effect of TR on glucose metabolism. Thus, periodic fasting contributes to some metabolic benefits of CR, but TR is metabolically different from CR. This difference might contribute to differential effects of CR and TR on longevity. Abstract : Periodic fasting does not affect blood glucose and glucose sensitivity, but has modest effect on glucose metabolism genes expression. Periodic fasting, on the other hand, reduces blood insulin and partially improves insulin sensitivity, thus indicating that some of the metabolic benefits observed on CR are due to periodic fasting. Partial improvement in insulin sensitivity under periodic fasting may provide mechanistic explanation for modest increase in lifespan on mealtime feeding.