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Subacute Ingestion of Caffeine and Oolong Tea Increases Fat Oxidation without Affecting Energy Expenditure and Sleep Architecture: A Randomized, Placebo-Controlled, Double-Blinded Cross-Over Trial.

  • 2020-11-28
  • Nutrients 12(12)
    • Simeng Zhang
    • Jiro Takano
    • Norihito Murayama
    • Morie Tominaga
    • Takashi Abe
    • Insung Park
    • Jaehoon Seol
    • Asuka Ishihara
    • Yoshiaki Tanaka
    • Katsuhiko Yajima
    • Yoko Suzuki
    • Chihiro Suzuki
    • Shoji Fukusumi
    • Masashi Yanagisawa
    • Toshio Kokubo
    • Kumpei Tokuyama

Study Design

Type
Randomized Controlled Trial (RCT)
Population
12 non-obese males
Methods
During each 14-day session of the present study, 12 non-obese males consumed oolong tea (100 mg caffeine, 21.4 mg gallic acid, 97 mg catechins and 125 mg polymerized polyphenol), caffeine (100 mg), or placebo at breakfast and lunch.
Duration
14 days
  • Rigorous Journal
Ingesting oolong tea or caffeine acutely increases energy expenditure, and oolong tea, but not caffeine, stimulates fat oxidation. The acute effects of caffeine, such as increased heart rate and interference with sleep, diminish over 1-4 days, known as caffeine tolerance. During each 14-day session of the present study, 12 non-obese males consumed oolong tea (100 mg caffeine, 21.4 mg gallic acid, 97 mg catechins and 125 mg polymerized polyphenol), caffeine (100 mg), or placebo at breakfast and lunch. On day 14 of each session, 24-h indirect calorimetry and polysomnographic sleep recording were performed. Caffeine and oolong tea increased fat oxidation by ~20% without affecting energy expenditure over 24-h. The decrease in the respiratory quotient by oolong tea was greater than that by caffeine during sleep. The effect of oolong tea on fat oxidation was salient in the post-absorptive state. These findings suggest a role of unidentified ingredients in oolong tea to stimulate fat oxidation, and this effect is partially suppressed in a postprandial state. Two weeks of caffeine or oolong tea ingestion increased fat oxidation without interfering with sleep. The effects of subacute ingestion of caffeine and oolong tea differed from the acute effects, which is a particularly important consideration regarding habitual tea consumption.

Research Insights

  • Oolong Tea→Altered Sleep Architecture

    Two weeks of caffeine or oolong tea ingestion increased fat oxidation without interfering with sleep.

    Effect
    Neutral
    Effect size
    Small
    Dose
    100 mg caffeine, 21.4 mg gallic acid, 97 mg catechins and 125 mg polymerized polyphenol
  • Oolong Tea→Increased Energy Expenditure

    Caffeine and oolong tea increased fat oxidation by ~20% without affecting energy expenditure over 24-h.

    Effect
    Neutral
    Effect size
    Small
    Dose
    100 mg caffeine, 21.4 mg gallic acid, 97 mg catechins and 125 mg polymerized polyphenol
  • Oolong Tea→Increased Fat Oxidation

    Caffeine and oolong tea increased fat oxidation by ~20% without affecting energy expenditure over 24-h.

    Effect
    Beneficial
    Effect size
    Small
    Dose
    100 mg caffeine, 21.4 mg gallic acid, 97 mg catechins and 125 mg polymerized polyphenol
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