The Roles of Diet, Exercise, & Supplements in Parkinson's Disease Progression MDS Abstracts Natural variation in age related dopamine neuron degeneration is glutathione dependent and linked to life span PNAS Figure 1 from The Role of Oxidative Stress in Parkinson's Disease Semantic Scholar Alterations in glutathione levels in Parkinson's disease and other neurodegenerative disorders affecting basal ganglia Sian 1994 Annals of Neurology Wiley Online Library