Policy Brief Based on Published Clinical Evidence: Melatonin Supplementation in Metabolic Syndrome: A Policy Brief Based on Evidence from a Randomized Clinical Trial

Abstract

Context: Metabolic syndrome (MetS) is associated with oxidative stress, endothelial dysfunction, and increased cardiometabolic risk. Melatonin has antioxidant and anti-inflammatory properties and may be relevant to the metabolic and inflammatory pathways involved in MetS. Objectives: This policy brief summarizes and translates findings from a previously published randomized, double-blind, placebo-controlled clinical trial evaluating the effects of melatonin supplementation on biomarkers of oxidative stress and endothelial function in adults with MetS. Evidence Acquisition: The underlying trial included adults with MetS who received melatonin (6 mg/day) or a visually similar placebo for 12 weeks. This policy brief summarizes the reported effects on serum endothelin-1 (ET-1), malondialdehyde (MDA), and superoxide dismutase (SOD) activity and considers their potential policy and research implications. Results: Among the analyzed participants, 31 received melatonin and 32 received placebo. After 12 weeks, ET-1 decreased from 1.55 ± 0.25 to 0.81 ± 0.18 pg/mL and MDA decreased from 1.33 ± 0.06 to 1.13 ± 0.05 μM in the melatonin group, whereas SOD activity increased from 23.64 ± 2.78 to 41.35 ± 1.22 U/mL. The corresponding within-group changes were not statistically significant in the placebo group. In baseline-adjusted between-group analyses, the intervention was associated with significant differences between groups in SOD activity (P = 0.001) and MDA (P = 0.022), whereas the between-group difference in ET-1 was not statistically significant (P = 0.682). Conclusions: The findings summarized in this policy brief suggest that melatonin supplementation may improve selected biomarkers of oxidative stress in adults with MetS. However, the evidence is based on a single, relatively small clinical trial with surrogate biomarker outcomes. Further multicenter studies with longer follow-up and assessment of clinical outcomes, safety, tolerability, and adherence are needed before routine clinical or policy implementation can be considered.