Melatonin supplementation and the effects on clinical and metabolic status in Parkinson's disease: A randomized, double-blind, placebo-controlled trial.

ABSTRACT

OBJECTIVE: This study was performed to evaluate the impact of melatonin supplementation on clinical and metabolic profiles in people with Parkinson's disease (PD). METHODS: This randomized, double-blind, placebo-controlled clinical trial was conducted among 60 patients with PD. Participants were randomly divided into two groups to intake either 10 mg melatonin (two melatonin capsules, 5 mg each) (n = 30) or placebo (n = 30) once a day, 1 h before bedtime for 12 weeks. RESULTS: Melatonin supplementation significantly reduced the Unified Parkinson's Disease Rating Scale (UPDRS) part I score (ß -2.33; 95% CI, -3.57, -1.09; P < 0.001), Pittsburgh Sleep Quality Index (PSQI) (ß -1.82; 95% CI, -3.36, -0.27; P = 0.02), Beck Depression Inventory (BDI) (ß -3.32; 95% CI, -5.23, -1.41; P = 0.001) and Beck Anxiety Inventory (BAI) (ß -2.22; 95% CI, -3.84, -0.60; P = 0.008) compared with the placebo treatment. Compared with the placebo, melatonin supplementation resulted in a significant reduction in serum high sensitivity C-reactive protein (hs-CRP) (ß -0.94 mg/L; 95% CI, -1.55, -0.32; P = 0.003) and a significant elevation in plasma total antioxidant capacity (TAC) (ß 108.09 mmol/L; 95% CI, 78.21, 137.97; P < 0.001) and total glutathione (GSH) levels (ß 77.08 µmol/L; 95% CI, 44.29, 109.86; P < 0.001). Additionally, consuming melatonin significantly decreased serum insulin levels (ß -1.79 µIU/mL; 95% CI, -3.12, -0.46; P = 0.009), homeostasis model of assessment-insulin resistance (HOMA-IR) (ß -0.47; 95% CI, -0.80, -0.13; P = 0.007), total- (ß -13.16 mg/dL; 95% CI, -25.14, -1.17; P = 0.03) and LDL- (ß -10.44 mg/dL; 95% CI, -20.55, -0.34; P = 0.04) compared with the placebo. CONCLUSIONS: Overall, melatonin supplementation for 12 weeks to patients with PD had favorable effects on the UPDRS part I score, PSQI, BDI, BAI, hs-CRP, TAC, GSH, insulin levels, HOMA-IR, total-, LDL-cholesterol, and gene expression of TNF-α, PPAR-γ and LDLR, but did not affect other metabolic profiles.