Beneficial Effects of Mild Stress (Hormetic Effects): Dietary Restriction and Health

Abstract

Hormesis is defined as a dose-response phenomenon characterized by low-dose stimulation and highdose inhibition, and has been recognized as representing an overcompensation for mild environmental stress. The beneficial effects of mild stress on aging and longevity have been studied for many years. In experimental animals, mild dietary stress (dietary restriction, DR) without malnutrition delays most age-related physiological changes, and extends maximum and average lifespan. Animal studies have also demonstrated that DR can prevent or lessen the severity of cancer, stroke, coronary heart disease, autoimmune disease, allergy, Parkinson's disease and Alzheimer's disease. The effects of DR are considered to result from hormetic mechanisms. These effects were reported by means of various DR regimens, such as caloric restriction, total-nutrient restriction, alternate-day fasting, and short-term fasting. Mild dietary stress, including restriction of amount or frequency of intake, is the essence of DR. For more than 99% of their history, humans lived as hunter-gatherers and adapted to restrictions in their food supply. On the other hand, an oversufficiency of food for many today has resulted in the current global epidemic of obesity and obesity-related diseases. DR may be used, therefore, as a novel approach for therapeutic intervention in several diseases, when detailed information about effects of mild dietary stress on human health is obtained from clinical trials. J Physiol Anthropol 29(4): [127][128][129][130][131][132] 2010 Dietary Restriction (DR) and HormesisThe hormetic dose-response model is the most common and fundamental in the biological and biomedical sciences (Calabrese, 2008b). Hormesis is defined as a dose-response phenomenon characterized by low-dose stimulation and highdose inhibition. This dose-response curve typically appears as an inverted U-shape or J-shape (Calabrese, 2008ab). Hormesis represents an overcompensation for mild environmental stress (Calabrese, 2001) and is the mechanism for adaptive responses to low doses of harmful environmental stimuli (Calabrese, 2008a). These harmful conditions include not only toxic substances, but also any environmental stimulus with potentially deleterious consequences for the organism, such as an increase or decrease in temperature. A stimulus that induces a beneficial hormetic response is called a mild stress (Le Bourg, 2009). Mild stress appears to slightly increase lifespan and to increase resistance to some stresses (Le Bourg, 2009).Mild dietary stress (dietary restriction, DR) without malnutrition delays most age-related physiological changes and extends maximum and average lifespan in experimental animals (Weindruch and Sohal, 1997; Frame et al., 1998). The first evidence in rodents was reported by McCay et al. in 1935(McCay et al., 1935. Since then, similar observations have been made in various species, including fish (Comfort, 1963), flies (Partridge et al., 1987), worms (Klass, 1977, and yeast (Lin et al., 2000). More recently, DR wa...

Telomeres are elongated in rats exposed to moderate altitude

“…Furthermore, we found that HIF-1α and TERT expression and oxidative stress damage were parallel to the changes of telomere length. These findings support the beneficial effects of mild stress [29]. However, further studies are needed to explore alternative possibilities and elucidate the relationship between leukocyte telomere length and longevity in humans living at different altitudes.…”

Fasting Therapy for Treating and Preventing Disease - Current State of Evidence

“…Interestingly, this early mild stress response with a subsequent adaption process supports the view that fasting may be a characteristic example of hormesis [24]. Extended fasting over at least 5-7 days is further associated with increases in concentrations of growth hormone, glucagon, and reductions of the blood levels of thyrotropin (TSH) and T 3 /T 4 [49,50].…”

“…Such a beneficial action and compensation of low-intensity environmental stressors can be classified as a hormetic response or hormesis, which describes a biological dose-response phenomenon characterized by low-dose stimulation and high-dose inhibition [24,25]. Other examples of moderate or intermittent stressors inducing hormesis are exercise, UV radiation, and ischemic preconditioning [26].…”

Metabolic and Psychological Response to 7-Day Fasting in Obese Patients with and without Metabolic Syndrome

“…Reduction of inflammatory markers has been described in experimental studies [40]. To the contrary, shorter periods of fasting may lead to a mild stress or hormetic reaction [41] which is associated with increased circulating levels of catecholamines and thereby possibly leading to an acute phase response. Hormetic effects are characterized as an overcompensation of low dose stimulation and stress and are related to human health.…”