Reduced fat mass and increased lean mass in response to 1 year of melatonin treatment in postmenopausal women: A randomized placebo-controlled trial.
OBJECTIVE
Apart from regulating the circadian rhythm, melatonin exerts a variety of actions in the living organism. Among these functions, melatonin is believed to have a positive effect on body weight and energy metabolism. So far, the evidence for this relies mainly on animal models. In this study, we aimed to determine the effects of melatonin on body composition, lipid and glucose metabolism in humans.


METHODS
In a double-blind, placebo-controlled study, we randomized 81 postmenopausal women to 1 year of treatment with melatonin (1 or 3 mg nightly) or placebo. Body composition was measured by DXA. Measures were obtained at baseline and after 1 year of treatment along with leptin, adiponectin and insulin. Markers of glucose homeostasis were measured at the end of the study.


RESULTS
In response to treatment, fat mass decreased in the melatonin group by 6·9% (95% CI: 1·4%; 12·4%, P = 0·02) compared to placebo. A borderline significant increase in lean mass of 5·2% was found in the melatonin group compared to placebo (3·3%, (IQR:-1·7; 6·2) vs -1·9%, (IQR: -5·7; 5·8), P = 0·08). After adjusting for BMI, lean mass increased by 2·6% (95% CI: 0·1; 5·0, P = 0·04) in the melatonin group. Changes in body weight and BMI did not differ between groups. Adiponectin increased borderline significantly by 21% in the melatonin group compared to placebo (P = 0·08). No significant changes were observed for leptin, insulin or markers of glucose homeostasis.


CONCLUSIONS
Our results suggest a possibly beneficial effect of melatonin on body composition and lipid metabolism as 1 year of treatment reduces fat mass, increases lean mass and is associated with a trend towards an increase in adiponectin.
Department of Endocrinology and Internal Medicine (MEA), THG, Aarhus University Hospital, Aarhus, Denmark.
Anne Kristine
AK
Amstrup
Department of Endocrinology and Internal Medicine (MEA), THG, Aarhus University Hospital, Aarhus, Denmark.
Tanja
T
Sikjaer
Department of Endocrinology and Internal Medicine (MEA), THG, Aarhus University Hospital, Aarhus, Denmark.|Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
Steen B
SB
Pedersen
Department of Clinical Biochemistry, THG, Aarhus University Hospital, Aarhus, Denmark.
Lene
L
Heickendorff
Department of Endocrinology and Internal Medicine (MEA), THG, Aarhus University Hospital, Aarhus, Denmark.
Leif
L
Mosekilde
Department of Endocrinology and Internal Medicine (MEA), THG, Aarhus University Hospital, Aarhus, Denmark.|Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
Lars
L
Rejnmark
D052242:Adiponectin / Q000097:blood; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism; D000368:Aged; D000975:Antioxidants / Q000008:administration & dosage / Q000627:therapeutic use; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood; D050356:Lipid Metabolism / Q000187:drug effects*; D008550:Melatonin / Q000008:administration & dosage / Q000627:therapeutic use*; D008875:Middle Aged; D017698:Postmenopause; D013997:Time Factors; D016896:Treatment Outcome
D052242:Adiponectin; D000975:Antioxidants; D001786:Blood Glucose; D007328:Insulin; D020738:Leptin; D005947:Glucose; D008550:Melatonin