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HormesisIn the mechanism, as is the case with calorie restriction, the factor has the opposite effect in small doses than in large doses. The potential of hormetic mechanisms in anti aging has been demonstrated in several studies. These mechanisms have included mild heat stress (RMHS), pro-oxidants, aldehydes, calorie restriction, irradiation, heat shock, and hypergravity. In one study, it was reported that repeated mild heat stress (RMHS) has anti-aging hormetic effects on growth and various cellular and biochemical characteristics of human skin fibroblasts undergoing aging in vitro. It was also reported that the RMHS mechanism prolonged the lifespan of Drosophila, or small fruit flies. There are researchers that suggest that the wide-ranging anti aging benefits of calorie restriction come from the hormesis effect. Following this thinking, a mild stress imposed by a reduced calorie intake acts as a stimulant for the survival against insults of disease-causing oxidative stress. It is believed that this resistive ability was acquired through the evolutionary process by maximizing the energy utilization by allocating only for the essential life supporting systems. What is interesting is that studies on gene expression profiles of calorie restricted animals have produced supporting data. For example, Lee et al. have reported that out of 6347 genes activated under calorie restricted condition, 16% were stress response, and 13% were related to energy metabolism, which suggests that the metabolic shifts are directed to prioritize the energy utilization only for essential defense processes. Cao et al. further report that animals in their study reacted to reduced feeding by turning on the molecular machinery for the metabolic adjustment within a few weeks as exhibited by the differential gene expression. Hormesis - StudiesHormesis and the antiaging action of dietary restriction. Masoro EJ. Exp Gerontol 1998, 33(1-2):61-6. Hormetic mechanisms of anti-aging and rejuvenating effects of repeated mild heat stress on human fibroblasts in vitro. Rattan SI. Rejuvenation Res, Vol. 7, No. 1. (2004), pp. 40-48. Hormesis and intervention of aging. Byung Pal Yu. Geriatrics and Gerontology International 2004;4: S81–S83.
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