Aging and the effect of calorie restriction in rhesus monkeys

Calorie restriction (CR), defined as the consumption of fewer calories in the absence of malnutrition, has been shown to decelerate the rate of aging and result in several health benefits in many short-lived species. Beginning about 20 years ago, well-controlled long-term studies initiated at both the National Institute on Aging and the Wisconsin National Primate Research Center have been investigating the effect of CR in long-lived rhesus monkeys, an animal model that closely recapitulates human biology. The studies were uniquely designed but share a common hypothesis that 30% CR will delay age-related diseases and increase lifespan in a long-lived mammal. Results from both studies have established a beneficial effect of CR in terms of body weight, body composition, insulin sensitivity, oxidative stress, and several hormone profiles or no detrimental effect on reproduction and sensory systems. More recently, work has focused on both behavioral and immune function alterations and thus this review emphasizes some of these findings and provides an update on female reproductive studies and sarcopenia.