The effect of caffeine, green tea and tyrosine on thermogenesis and energy intake
| Autor: | Søren Toubro, Anita Belza, Arne Astrup |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Adult
Male medicine.medical_specialty media_common.quotation_subject Appetite Medicine (miscellaneous) Blood Pressure Green tea extract Placebo Camellia sinensis Young Adult chemistry.chemical_compound Double-Blind Method Heart Rate Caffeine Internal medicine medicine Humans media_common Cross-Over Studies Nutrition and Dietetics Tea Plant Extracts business.industry Respiration Body Weight Thermogenesis Overweight Crossover study Respiratory quotient Endocrinology chemistry Basal metabolic rate Tyrosine Central Nervous System Stimulants Basal Metabolism Energy Intake business Phytotherapy |
| Zdroj: | European Journal of Clinical Nutrition. 63:57-64 |
| ISSN: | 1476-5640 0954-3007 |
| Popis: | To investigate the effect of three different food ingredients tyrosine, green tea extract (GTE) and caffeine on resting metabolic rate and haemodynamics, and on ad libitum energy intake (EI) and appetite.Twelve healthy, normal weight men (age: 23.7 +/- 2.6 years, mean +/- s.d.) participated in a four-way crossover, randomized, placebo-controlled, double-blind study. Treatments were administered as tablets of 500 mg GTE, 400 mg tyrosine, 50 mg caffeine, or placebo, and were separated by3-day washout. The acute thermogenic response was measured in a ventilated hood system for 4 h following ingestion. Blood pressure, heart rate (HR), and subjective appetite sensations were assessed hourly and ad libitum EI 4 h post-dose.Caffeine induced a thermogenic response of 6% above baseline value (72 +/- 25 kJ per 4 h, mean +/- s.e.) compared to placebo (P0.0001). The thermogenic responses to GTE and tyrosine were not significantly different from placebo. Tyrosine tended to increase 4-h respiratory quotient by 1% compared to placebo (0.01 +/- 0.005, P=0.05). Ad libitum EI was not significantly different between treatments but was reduced by 8% (-403 +/- 183 kJ), 8% (-400 +/- 335 kJ) and 3% (-151 +/- 377 kJ) compared to placebo after intake of tyrosine, GTE and caffeine, respectively. No significant difference in haemodynamics was observed between treatments.Only caffeine was thermogenic in the given dose and caused no haemodynamic side effects. The sample size was probably too small to detect any appetite suppressant properties of the treatments. Further investigations are required. |
| Databáze: | OpenAIRE |
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