Omega-3 fatty acids' supplementation in Parkinson's disease: A systematic review of randomized controlled trials

Summary: Parkinson's disease (PD) is a neurodegenerative disorder, in which loss of dopaminergic neurons is present among other alterations. Lipids are key molecules in PD pathophysiology. Patients with PD may have lower levels of circulating omega-3 fatty acids, which are vital components of the brain cells' membranes, exerting anti-inflammatory properties and affecting neural function. The present systematic review of randomized controlled trials (RCTs) assessed the potential beneficial effects of omega-3 fatty acids' supplementation in patients with PD. Several accurate databases were used, including PubMed, Cochrane, and Scopus, as well as grey literature sources. Four RCTs were finally identified, in which different doses of omega-3 fatty acids were administered together with vitamin E. Three RCTs investigated the effects of omega-3 fatty acids on the progression of PD with the use of Unified Parkinson's Disease Rating Stage (UPDRS) score, and all showed beneficial effects. Moreover, some beneficial effects were reported for depression scales, as well as against insulin resistance, markers of inflammation, and oxidative stress. However, further studies are highly recommended to substantiate the role of omega-3 fatty acids' supplementation in the clinical course of PD.