Isao Shimokawa, MD, PhD
Pathology & Gerontology,
Department of Respiratory and Digestive Medicine,
Nagasaki University School of Medicine,
Nagasaki, Japan.
Introduction
Caloric restriction (CR)--the restriction of food intake while maintaining adequate supplies of essential nutrients (i.e. not malnutrition)--is widely recognized as the most powerful intervention for the extension of lifespan in organisms. CR slows the aging process, prevents or retards age-related diseases and extends the mean and maximum lifespan in laboratory organisms.1,2 In the 66 years since the seminal report of McCay,3 many studies have confirmed its life-extending effects. These effects do not depend on the restriction of specific nutrients or food contaminants.4 Despite numerous efforts, our knowledge of the mechanisms underlying the effects of CR is not yet complete. The present article focuses on several possible mechanisms. Other historic and recent research can be found in more comprehensive reviews1,2 and a recent update.4
An Evolutionary Perspective
It has been suggested that the anti-aging effects of CR might derive from adaptive responses that evolved to maximize organism survival during periods of food shortage. In order to avoid extinction, organisms have evolved neuroendocrine and metabolic response systems to enhance survival during natural periods of food shortage.
