Background: Unlike sleep deprivation, caffeine in coffee has been shown to yield positive effects on appetite, body weight, and risk of developing symptoms of metabolic syndrome. However, the combined effects of caffeinated coffee and sleep deprivation are unknown. The aim of this study was to determine the simultaneous effects of coffee caffeine intake and sleep deprivation on leptin and ghrelin.
Methods: This was a randomized clinical trial comprised three-day treatments with two-week washout interval. Forty-two healthy men, habitual caffeinated coffee consumers (1-3 cups/day) and good sleepers (based on the Pittsburgh Sleep Quality Index) were recruited. Subjects were randomly assigned to three groups: three nights of deprived sleep (4 hrs. in bed) plus 3×150 mL/cup of boiled water (BW treatment), decaffeinated coffee (DC treatment, without sugar, 99.9% caffeine-free), and caffeinated coffee (CC treatment, without sugar, 65 mg caffeine/cup). DC and CC treatments were blinded. At the end, fasting serum leptin and plasma ghrelin were measured and compared.
Results: No significant differences were found between the treatments in the leptin level but a significant difference was shown between the treatments in plasma ghrelin (P=0.048). Pairwise comparisons test
showed that the CC treatment led to lower plasma ghrelin as compared to the DC treatment (P=0.006).
Conclusion: Caffeinated coffee with sleep deprivation simultaneously manipulated the level of ghrelin towards an anorexigenic effect (reduced plasma ghrelin). However, further investigations are required to support
caffeinated coffee as an appetite/weight loss recommendation.