BACKGROUND: Prolonged dietary restriction increases the life span in rodents. Some evidence suggests that alternate-day fasting may also prolong the life span. OBJECTIVE: Our goal was to determine whether alternate-day fasting is a feasible method of dietary restriction in nonobese humans and whether it improves known biomarkers of longevity. DESIGN: Nonobese subjects (8 men and 8 women) fasted every other day for 22 d.
Calorie restriction is the first and most compelling example of life extension in mammals. Much speculation about how CR works has focused on ideas of what causes aging. Since these causes themselves are much disputed, I have instead focused my thinking on lessons from simple model organisms, which have emerged from recent genetic studies. These findings can now be integrated with numerous, elegant studies on CR over the decades, which provide a treasure trove of information about physiological changes that are elicited by this regimen.
BACKGROUND: Adherence to a Mediterranean diet has been reported to increase longevity, but concerns have been expressed that such a diet may promote overweight and obesity. OBJECTIVE: The objective was to investigate whether adherence to the traditional Mediterranean diet, as operationalized in a Mediterranean diet score, is associated with body mass index (BMI) and waist-to-hip ratio (WHR).
Calorie restriction increases the life span of many organisms, from yeast to mammals. In yeast, the life span gene affected by calorie restriction is Sir2 (silent information regulator 2). In mammals, Sirt1, an ortholog of Sir2, controls the metabolism of white adipose tissue. Calorie restriction activates Sirt1, and the expressed Sirt1 protein inhibits the action of peroxysome proliferator-activator receptor gamma (PPARgamma), the nuclear receptor that promotes adipogenesis. The effect is lipolysis and loss of fat.
JAMA: the journal of the American Medical Association
CONTEXT: Prolonged calorie restriction increases life span in rodents. Whether prolonged calorie restriction affects biomarkers of longevity or markers of oxidative stress, or reduces metabolic rate beyond that expected from reduced metabolic mass, has not been investigated in humans. OBJECTIVE: To examine the effects of 6 months of calorie restriction, with or without exercise, in overweight, nonobese (body mass index, 25 to <30) men and women.
Dietary restriction (DR) lengthens life span in wide range of vertebrate and invertebrate species. The molecular mechanism by which DR increases life span and the universality of its effects (and hence its applicability to humans) are currently debated in gerontology. This article addresses these two problems from both an experimental perspective, using the nematode C. elegans as a model system, and a theoretical viewpoint, by appealing to recent mechanistic and evolutionary models of aging.
Elevated blood glucose associated with diabetes produces progressive and apparently irreversible damage to many cell types. Conversely, reduction of glucose extends life span in yeast, and dietary restriction reduces blood glucose. Therefore it has been hypothesized that cumulative toxic effects of glucose drive at least some aspects of the aging process and, conversely, that protective effects of dietary restriction are mediated by a reduction in exposure to glucose.