A recent study published in the Journal of Human Nutrition and Dietetics has found that higher intake of melatonin from foods is linked to lower rates of obesity and depression. The research analyzed data from 8,320 Brazilian university graduates participating in the Cohort of Universities of Minas Gerais (CUME+) study, which looks at how dietary patterns affect noncommunicable diseases.
Melatonin is a hormone found in both animal- and plant-based foods. Previous studies have suggested it may benefit sleep, mood, and metabolic health. In this study, researchers estimated melatonin content for 119 different food items using existing literature and adjusted intake values for total energy consumption.
Participants completed questionnaires on their health history, lifestyle habits, and diet. Researchers used statistical models to examine links between dietary melatonin intake and several health outcomes including obesity, depression, hypertension, type 2 diabetes (T2D), obstructive sleep apnea (OSA), metabolic syndrome (MetS), dyslipidemia, and sleep duration.
Coffee, lentils and beans, as well as rice were identified as the main sources of dietary melatonin. Men had higher average daily intakes than women. Higher melatonin intake was also associated with greater fiber and carbohydrate consumption but lower protein, cholesterol, saturated fat, and monounsaturated fat intake.
The results showed no significant relationship between dietary melatonin intake and OSA, hypertension, MetS or T2D after adjusting for age and sex. Any associations with sleep duration or dyslipidemia did not remain statistically significant after similar adjustments.
However, people who consumed moderate amounts of dietary melatonin—between 14,900 to 34,400 ng per day—were less likely to be obese or depressed compared to those with lower intakes. The strongest associations were seen among those with intermediate levels rather than the highest quintile.
"Dietary melatonin intake was inversely associated with depression and obesity in this population," the authors wrote. "No significant associations were observed for other chronic conditions or sleep duration."
The researchers caution that because their analysis was cross-sectional—that is based on data collected at one point in time—they cannot say whether eating more melatonin-rich foods directly causes lower rates of obesity or depression. They call for further experimental studies to confirm these findings and better understand how dietary melatonin might influence health through anti-inflammatory pathways.
