Melatonin supplementation to treat the metabolic syndrome: a randomized controlled trial.
BACKGROUND
Supplemental melatonin may ameliorate metabolic syndrome (MetS) components, but data from placebo-controlled trials are lacking.


METHODS
We conducted a double-blind, placebo-controlled, crossover, Phase II randomized pilot clinical trial to estimate the effects of melatonin supplementation on MetS components and the overall prevalence of MetS. We randomized 39 subjects with MetS to receive 8.0 mg oral melatonin or matching placebo nightly for 10 weeks. After a 6-week washout, subjects received the other treatment for 10 more weeks. We measured waist circumference, triglycerides, HDL cholesterol, fasting glucose, and blood pressure (BP) in each subject at the beginning and end of both 10-week treatment periods. The primary outcome was the mean 10-week change in each MetS component, and a secondary outcome was the proportion of subjects free from MetS, after melatonin versus placebo.


RESULTS
The mean 10-week change for most MetS components favored melatonin over placebo (except fasting glucose): waist circumference -0.9 vs. +1.0 cm (p = 0.15); triglycerides -66.3 vs. -4.2 mg/dL (p = 0.17); HDL cholesterol -0.2 vs. -1.1 mg/dL (p = 0.59); fasting glucose +0.3 vs. -3.1 mg/dL (p = 0.29); systolic BP -2.7 vs. +4.7 mmHg (p = 0.013); and diastolic BP -1.1 vs. +1.1 mmHg (p = 0.24). Freedom from MetS tended to be more common following melatonin versus placebo treatment (after the first 10 weeks, 35.3% vs. 15.0%, p = 0.25; after the second 10 weeks, 45.0% vs. 23.5%, p = 0.30). Melatonin was well-tolerated.


CONCLUSIONS
Melatonin supplementation modestly improved most individual MetS components compared with placebo, and tended to increase the proportion of subjects free from MetS after treatment.


BACKGROUND
NCT01038921, clinicaltrials.gov.
Department of Medicine, Division of Cardiology, Emory University School of Medicine, Atlanta, GA USA ; Department of Epidemiology, Emory Rollins School of Public Health, Atlanta, GA USA.
Abhinav
A
Goyal
Departments of Surgery and Public Health, University of Tennessee, 1914 Andy Holt Ave., HPER 390, Knoxville, TN 37996 USA.
Paul D
PD
Terry
Department of Biostatistics and Bioinformatics, Emory Rollins School of Public Health, Atlanta, GA USA.
Hillary M
HM
Superak
Emory Center for Heart Disease Prevention, Emory Healthcare, Atlanta, GA USA.
Christine L
CL
Nell-Dybdahl
Department of Epidemiology, Emory Rollins School of Public Health, Atlanta, GA USA ; James T. Laney School of Graduate Studies, Emory University, Atlanta, GA USA.
Ritam
R
Chowdhury
Department of Medicine, Division of Endocrinology, Emory University School of Medicine, Atlanta, GA USA.
Lawrence S
LS
Phillips
Department of Biostatistics and Bioinformatics, Emory Rollins School of Public Health, Atlanta, GA USA.
Michael H
MH
Kutner
Melatonin; Metabolic syndrome; Randomized controlled trial