Antioxidants, supplements, and Parkinson's disease

OBJECTIVE: To review the use of antioxidants and other supplements for the prevention and treatment of Parkinson's disease (PD). DATA SOURCES: Biomedical literature was accessed through MEDLINE (1996-June 2005); key search terms included Parkinson's disease, coenzyme Q10 (CoQ10), antioxidants, supplements, and glutathione. Pertinent references cited in those articles were also evaluated for inclusion in this review. DATA SYNTHESIS: Three main antioxidants or supplements have been studied for use in the prevention or treatment of PD: tocopherol, CoQ10, and glutathione. These agents have been studied because of their potential to alter the course of 2 common theories of PD pathogenesis: free radical generation and mitochondrial complex-1 deficiency. The literature search revealed 3 large clinical studies of tocopherol (2 observational, 1 prospective randomized), 4 trials of CoQ10, and 1 study of glutathione. With the exception of the large observational studies with tocopherol and one study of CoQ10 that enrolled 80 patients, each of the other studies retrieved included fewer than 30 patients and were conducted for 3 months or less. Antioxident supplementation, in particular tocopherol, did not appear to alter the course of PD. However, in 2 of the studies of CoQ10 and in the study of glutathione, a small but statistically significant improvement in PD symptoms was observed. CONCLUSIONS: At present, antioxidants and supplements appear to have a limited role in the prevention or treatment of PD. Of those reviewed here, CoQ10 appears to provide some minor treatment benefits. More study is necessary to determine whether CoQ10 has a significant role as primary or adjunctive therapy in PD.