Research studies clearly indicate that age-related changes in cellular and tissue function are linked to decreases in the anabolic hormones, growth hormone and insulin-like growth factor (IGF)-1. Although there has been extensive research on the effects of these hormones on bone and muscle mass, their effect on cerebrovascular and brain ageing has received little attention.
In a long-term longitudinal study of aging in rhesus monkeys, a primary objective has been to determine the effects of aging and caloric restriction (CR) on behavioral and neural parameters. Through the use of automated devices, locomotor activity can be monitored in the home cages of the monkeys. Studies completed thus far indicate a clear age-related decline in activity consistent with such observations in many other species, including humans. However, no consistent effects of CR on activity have been observed.
Fundamental questions on the pathogenesis of Alzheimer's disease (AD) are how nontoxic, soluble amyloid beta-protein (A beta) is converted to its toxic, aggregated form and how functional tau is hyperphosphorylated to form neurofibrillary tangles. Growing evidence from recent biochemical and cell biological studies suggests that altered cholesterol metabolism in neurons may underlie such pathological processes. The possibility that cholesterol is a risk factor in the development of AD has also been supported by recent epidemiological studies.
Intermittent fasting (IF; reduced meal frequency) and caloric restriction (CR) extend lifespan and increase resistance to age-related diseases in rodents and monkeys and improve the health of overweight humans. Both IF and CR enhance cardiovascular and brain functions and improve several risk factors for coronary artery disease and stroke including a reduction in blood pressure and increased insulin sensitivity. Cardiovascular stress adaptation is improved and heart rate variability is increased in rodents maintained on an IF or a CR diet.
The size and frequency of meals are fundamental aspects of nutrition that can have profound effects on the health and longevity of laboratory animals. In humans, excessive energy intake is associated with increased incidence of cardiovascular disease, diabetes, and certain cancers and is a major cause of disability and death in industrialized countries. On the other hand, the influence of meal frequency on human health and longevity is unclear.
The American Journal of Geriatric Psychiatry: Official Journal of the American Association for Geriatric Psychiatry
OBJECTIVE: The objective of this study was to determine the effects of a 14-day healthy longevity lifestyle program on cognition and cerebral metabolism in people with mild age-related memory complaints.
The vulnerability of the nervous system to advancing age is all too often manifest in neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. In this review article we describe evidence suggesting that two dietary interventions, caloric restriction (CR) and intermittent fasting (IF), can prolong the health-span of the nervous system by impinging upon fundamental metabolic and cellular signaling pathways that regulate life-span.
Caloric restriction has wide-ranging health benefits and may offer protection against age-related neuronal loss and neurodegenerative disorders such as Alzheimer's disease, possibly via enhanced adult neurogenesis. While a variety of interventions such as exercise increase neurogenesis, recent work suggests that exercise and caloric restriction may work to enhance neurogenesis by different neurobiological mechanisms, suggesting a role for both diet and exercise in disease prevention.