Does Dietary Melatonin Play a Role in Bone Mineralization

Introduction: Melatonin is generated as a product of normal circadian rhythm and is also is thought to play an important role in maintaining bone mineral density (BMD) by reducing chronic inflammation. Postmenopausal women are at an elevated risk of BMD loss due to declining estrogen and a natural decrease in melatonin synthesis with increasing age. Endogenous melatonin production is largely influenced by exposure to external light cues, but recent research has indicated that serum melatonin may be increased by the consumption of melatonin-rich foods. The purpose of this study was to quantify dietary-derived melatonin and examine its effects on inflammation, BMD, and sleep in a sample of postmenopausal women.;Methods: Cross-sectional analysis of data from the National Health and Nutrition Examination Survey (NHANES) was conducted to examine differences in melatonin consumption, BMD, and sleep in postmenopausal women with chronic and low-level inflammation indicated by level of C-reactive protein (CRP). Data from the years 2005--2010 was included in this study.;Results: 110 postmenopausal women were included in the analysis with 55 subjects included in each inflammatory group. Individuals with normal CRP had a significantly greater intake of dietary melatonin (p=0.03) and higher BMD (p<0.05) than individuals with chronic inflammation. Normal inflammatory subjects also had a significantly higher intake of folate (p<0.0001), vitamin B6 (p=0.0005), and magnesium (p=0.0005) than subjects with chronic inflammation. Hours of sleep did not differ significantly with CRP level (p=1.0). Individuals with chronic inflammation exhibited a negative correlation between BMD and CRP (r= --0.27, p=0.04).;Conclusions: The results suggest that dietary-derived melatonin may play an underlying role in mitigating inflammation and increasing BMD in postmenopausal women by reducing inflammation and oxidative stress. Melatonin may enhance the effects of other antioxidants and anti-inflammatory nutrients, and is part of dietary patterns rich in plant foods. Foods with melatonin also contain a variety of nutrients that act as coenzymes and cofactors for synthesis of endogenous melatonin.