Calorie Restriction and Aging

Abstract SCI-2

A prominent manifestation of aging is a reduced ability to respond to environmental stressors, including heat and oxidative stress. Reduced stress tolerance and decreased ability to maintain homeostasis are at least partially responsible for the increased morbidity and mortality that occurs with advancing age. The age-related attenuation of stress pathways and increased expression of stress-response genes with aging are examples of the growing body of evidence linking reduced stress responsiveness to aging. In 1935, McCay and colleagues first reported that reducing the caloric intake of rodents could significantly lengthen their mean and maximal life span, slowing down basic aging processes. The effect of calorie restriction (CR) on delaying aging has been replicated in many animal species including nonhuman primates, although in these, potential life span alterations cannot be ascertained for several more years due to their longevity CR causes a reduction in body weight, tissue growth, blood glucose, insulin levels and body temperature. In addition, CR prevents the age-related decline in tolerance to different stressors such as oxidative and heat, and the age-related reduction in expression of protective heat shock and oxidative stress proteins. While CR is the only intervention that has consistently been shown to increase maximum life span and prevent or delay the onset of age-associated pathophysiological changes in laboratory rodents, the underlying mechanisms remain elusive. Using calorie restriction (CR) as their benchmark research tool, gerontologists are making progress in identifying dietary and pharmacologic interventions that may be applicable to retarding aging processes in humans.