Oxidative stress, which is caused by endogenous and exogenous reactive-oxygen-species (ROS) formation, may significantly affect health-span and longevity. Endogenous oxidative stress could be attenuated in two ways: by the reduction of ROS formation and by quenching ROS with antioxidants. Numerous results of clinical trials in which individuals received one or more synthetic antioxidants failed to demonstrate conclusive benefits of antioxidant supplementation. Even oral supplementation with endogenous antioxidant enzymes cannot alter the antioxidant balance due to their degradation in the digestive system. Likewise, life-span or health-span is not increased significantly in genetically modified models overexpressing antioxidant enzymes. An alternative approach to attenuate the ROS-induced stress/damage may be through triggering an adaptive stress response in order to increase the endogenous antioxidant and damage repair processes. Moderate stress induced by CR, physical activity or mimetic compounds may induce such activation of endogenous antioxidative defence and cellular repair processes. These processes may increase cellular resistance to subsequent more severe stress and do not seem to interfere with ROS-dependent cellular signalling.

The book offers a comprehensive review of current research regarding the influences of environmental factors involved in human health and ageing. Many environmental compounds promote excessive oxidative stress, which is the primary cause of accelerated ageing and which also contributes to the development of human diseases. The basic concepts of ageing theories are discussed, as is the promotion of oxidative stress which has been identified as one of the most important mechanisms responsible for the toxic effects of the majority of environmental pollutants. Antioxidants play an important role in the defence against pollutant-induced toxicity.

This book describes mechanisms of skin damage generation and examines the potential impact of free radicals, reactive oxygen species (ROS) and oxidative damage on the skin ageing process. It also evaluates methods to decrease skin oxidative stress, oxidative damage, and skin ageing. The identification of free radical reactions as promoters of the skin ageing process implies that interventions aimed at limiting or inhibiting free radical reactions should be able to reduce the rate of formation of ageing-related changes with a consequent reduction of the ageing rate. This book highlights how ageing of the skin happens, as well as what are the causes and the best ways to prevent and treat it.

Ageing is an inevitable biological process that affects most living organisms. The link between metabolic rate and reactive oxygen species production is an important and long-standing question, and a source of much controversy. A by-product of cell respiration in mitochondria is the formation of reactive oxygen species due to electron leakage from the electron transport chain during oxidative phosphorylation. In simple terms, humans are ageing due to oxygen consumption. Damage induced by oxygen appears to be the major contributor to ageing and the degenerative diseases of ageing such as cancer, cardiovascular disease, immune system decline, and brain dysfunction. This book presents the reasons for oxidative stress formation and the answer to why during the course of evolution the process of free radical damage and defense did not become more perfect so as to produce less free radicals.