Free Radicals and Antioxidants: A new Paradigm has emerged

Abstract

Despite the tremendous progress Redox Biology has made since the turn of the century, several misconceptions about free radicals with Reactive Oxygen Species most prominently among them and about their neutralization by antioxidants still seem to permeate the literature and common thinking as well: First, all Reactive Oxygen Species are toxic byproducts of mitochondrial respiration and as such cause oxidative damage to biological macromolecules. Second, fundamental differences in terms of reactivity and stability between Reactive Oxygen Species are generally neglected and they are widely still being treated as one chemical entity. Third, mitochondria are the major source of toxic Reactive Oxygen Species and fourth, low-molecular weight natural or synthetic antioxidants scavenge free radicals and thereby diminish oxidative damage. This review will debunk these four faulty assumptions, critically address the failure of large-scale clinical trials involving low-molecular weight antioxidants and subsequently propose a new mechanism of action underlying the undisputable health benefits of nutritional antioxidants in fruits and vegetables. In summary, it will be shown that data published during the last two decades by leading investigators in the field of Redox Biology provide the ground for a paradigm change regarding free radicals and antioxidants in human health and disease.