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Anti-Aging and Regenerative Medicine
Published in Aruna Bakhru, Nutrition and Integrative Medicine, 2018
In 1908, Max Rubner noted an association between metabolic rate, body size, and longevity. He hypothesized that animals are born with a limited amount of some substance, physiological capacity or potential energy, the duration of life depends on the expenditure rate of this energy. The faster they use it, the faster they will die. Later in 1928, Raymond Pearl proposed “the rate of living theory” based on Ruber's hypothesis suggesting that “the higher the metabolic rate, the higher will be the biochemical activity and the faster an organism will age” (Bennett et al. 2012, Pearl 1928).
Introduction
Published in Alvaro Macieira-Coelho, Molecular Basis of Aging, 2017
The stress hypothesis is a variant, although more specific, of the “rate of living” theory. This theory claimed that the duration of life varies in inverse proportion to the rate of energy expended, as a result of a finite, total amount of “vitality” being used. This proposal eventually acquired a scientific basis when a correlation was ascertained between life span and metabolic rate and temperature.2
Aging and Cardiovascular Disease
Published in Nathalie Bergeron, Patty W. Siri-Tarino, George A. Bray, Ronald M. Krauss, Nutrition and Cardiometabolic Health, 2017
Jasper Most, Leanne M. Redman, Nathalie Bergeron, Patty W. Siri-Tarino, George A. Bray, Ronald M. Krauss
Related to the rate of living theory is the oxidative damage theory of aging. Of all oxygen consumed by the electron transport chain, 1%–3% is reduced to oxygen radicals by leaking electrons. Leaking electrons are electrons that are not properly transferred along the electron transport chain and therefore diffuse back into the mitochondrial matrix. The generated oxygen radicals can accumulate in cells as toxic reactive oxygen species (ROS) (Alexeyev, Ledoux, and Wilson 2004), which in turn leads to damage to the electron transport chain and to the mitochondrial DNA. This elicits a vicious cycle, because the damaged electron transport chain leads to increased leakage of more electrons, which ultimately leads to a decline in physiological function and aging (Sohal and Weindruch 1996). Together these two theories posit that a reduction in the rate of living or metabolic rate due to CR (and hence oxygen trafficked through electron transport chain) causes fewer ROS to be accumulated. Over time, it is hypothesized that decreased accumulation of ROS yields less oxidative damage to lipids, proteins, and DNA, thereby leading to an attenuation in the rate of primary aging.
Nutrient effects on working memory across the adult lifespan
Published in Nutritional Neuroscience, 2023
Selene Cansino, Frine Torres-Trejo, Cinthya Estrada-Manilla, Adriana Flores-Mendoza, Gerardo Ramírez-Pérez, Silvia Ruiz-Velasco
Increasing energy intake was associated with lower working memory performance in individuals older than 40 years old but not in younger participants. Two prominent theories that attempt to explain the aging process claim that lowering metabolism rates could delay this process. One of them, the free radical theory, proposes that aging is the consequence of oxidative stress caused by the production of free radicals generated through normal cellular metabolism [45]. Similarly, the rate of living theory proposes that metabolism rates determine longevity, based on larger animals with lower metabolism rates living longer than small animals with fast metabolism rates [46]. Therefore, decreasing metabolism rates by reducing energy intake delays aging and related consequences, such as cognitive decline. Moreover, there is evidence that a calorie-restricted diet reduces neuroinflammation and induces neurogenesis [47], mechanisms that might also explain the benefits we found on memory.
Regulatory systems that mediate the effects of temperature on the lifespan of Caenorhabditis elegans
Published in Journal of Neurogenetics, 2020
Byounghun Kim, Jongsun Lee, Younghun Kim, Seung-Jae V. Lee
Temperature is an important environmental factor, which affects lifespan and aging. The ‘rate-of-living’ theory asserts that the faster the metabolism, the shorter the lifespan (Pearl, 1928). Therefore, it was widely accepted that chemical reactions are facilitated as temperature rises, leading to increased metabolic rates and consequently short lifespan. This scenario is particularly plausible for ectotherms, whose body temperatures are subject to changes in environmental temperatures. Interestingly, however, many studies using ectotherms, including C. elegans, indicate that genetic factors modulate lifespan changes in response to external temperatures (Jeong, Artan, Seo, & Lee, 2012; Xiao, Liu, & Xu, 2015).