This randomized, double-blind, placebo-controlled trial evaluated the effects of melatonin administration on metabolic status in 60 diabetic patients with coronary heart disease (CHD).

Subjects were allocated into two groups to receive either 10 mg melatonin (2 melatonin capsules, 5 mg each) (n = 30) or placebo (n = 30) once a day for 12 weeks.

Taking melatonin, compared with the placebo, significantly reduced fasting plasma glucose (p = 0.03), serum insulin concentrations (p = 0.008), homeostasis model of assessment-estimated insulin resistance (p = 0.04), total-/HDL-cholesterol ratio (p = 0.02) and systolic (p = 0.01) and diastolic blood pressure (p = 0.04). Melatonin treatment also significantly increased quantitative insulin sensitivity check index (p = 0.01) and serum HDL-cholesterol (p = 0.04).

In addition, compared with the placebo, melatonin supplementation resulted in significant increases in plasma glutathione (p = 0.02) and nitric oxide (p = 0.03), and significant decreases in malondialdehyde (p = 0.007), protein carbonyl (p < 0.001) and serum high sensitivity C-reactive protein levels (p = 0.001).

Overall, melatonin intake for 12 weeks to diabetic patients with CHD had beneficial effects on biomarkers of oxidative stress and cardio-metabolic risk.

Raygan F, Ostadmohammadi V, Bahmani F, Reiter RJ, Asemi Z. Melatonin administration lowers biomarkers of oxidative stress and cardio-metabolic risk in type 2 diabetic patients with coronary heart disease: A randomized, double-blind, placebo-controlled trial. Clin Nutr. 2019 Feb;38(1):191-196.