Hormesis

Hormesis is any process in a cell or organism that exhibits a biphasic response to exposure to increasing amounts of a substance or condition. Within the hormetic zone, there is generally a favorable biological response to low exposures to toxins and other stressors. Hormesis comes from Greek hórmēsis “rapid motion, eagerness”, itself from ancient Greek hormáein “to set in motion, impel, urge on”. Hormetics is the term proposed for the study and science of hormesis.

Since the basic survival capacity of any biological system depends on its homeostatic ability, biogerontologists proposed that exposing cells and organisms to mild stress should result in the adaptive or hormetic response with various biological benefits. This idea has now gathered a large body of supportive evidence showing that repetitive mild stress exposure has anti-aging effects. Exercise is a paradigm for hormesis in this respect.

Some of the mild stresses used for such studies on the application of hormesis in aging research and interventions are heat shock, irradiation, prooxidants, hypergravity, and food restriction.

Some other natural and synthetic molecules, such as celastrols from medicinal herbs and curcumin from the spice turmeric have also been found to have hormetic beneficial effects. Such compounds which bring about their health beneficial effects by stimulating or by modulating stress response pathways in cells have been termed “hormetins”. Hormetic interventions have also been proposed at the clinical level, with a variety of stimuli, challenges and stressful actions, that aim to increase the dynamical complexity of the biological systems in humans.

SOURCE: Wikipedia




Dietary factors, hormesis + health

Abstract

The most prominent dietary factor that affects the risk of many different chronic diseases is energy intake — excessive calorie intake increases the risk. Reducing energy intake by controlled caloric restriction or intermittent fasting increases lifespan and protects various tissues against disease, in part, by hormesis mechanisms that increase cellular stress resistance.

Some specific dietary components may also exert health benefits by inducing adaptive cellular stress responses. Indeed, recent findings suggest that several heavily studied phytochemicals exhibit biphasic dose responses on cells with low doses activating signaling pathways that result in increased expression of genes encoding cytoprotective proteins including antioxidant enzymes, protein chaperones, growth factors and mitochondrial proteins. Examples include: activation of the Nrf-2 – ARE pathway by sulforaphane and curcumin; activation of TRP ion channels by allicin and capsaicin; and activation of sirtuin-1 by resveratrol.

Research that establishes dose response and kinetic characteristics of the effects of dietary factors on cells, animals and humans will lead to a better understanding of hormesis and to improvements in dietary interventions for disease prevention and treatment.

SOURCE: Ageing Research Reviews