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Eur J Clin Nutr. 2005 Jun;59(6):733-41.

Bioactive food stimulants of sympathetic activity: effect on 24-h energy expenditure and fat oxidation.

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Department of Human Nutrition, Centre for Advanced Food Studies, The Royal Veterinary and Agricultural University, Frederiksberg, Denmark.



Bioactive food ingredients influence energy balance by exerting weak thermogenic effects. We studied whether the thermogenic effect of a combination of capsaicin, green tea extract (catechins and caffeine), tyrosine, and calcium was maintained after 7-day treatment and whether local effects in the gastric mucosa were involved in the efficacy.


The present study was designed as a 3-way crossover, randomised, placebo-controlled, double-blinded intervention.


Department of Human Nutrition, RVAU, Denmark.


A total of 19 overweight to obese men (BMI: 28.0+/-2.7 kg/m2) were recruited by advertising locally.


The subjects took the supplements for a period of 7 days. The supplements were administrated as a simple supplement with the bioactive ingredients, a similar enterocoated version, or placebo. In all, 24-h energy expenditure (EE), substrate oxidations, spontaneous physical activity (SPA), and heart rate were measured in respiration chambers on the seventh day of each test period.


After adjustment for changes in body weight and SPA, 24-h EE was increased by 160 kJ/day (95% CI: 15-305) by the simple preparation as compared to placebo, whereas the enterocoated preparation had no such effect (53 kJ/day, -92 to 198); simple vs enterocoated versions (P=0.09). The simple preparation produced a deficit in 24-h energy balance of 193 kJ/day (49-338, P=0.03). Fat and carbohydrate oxidation were equally increased by the supplements.


A supplement containing bioactive food ingredients increased daily EE by approximately 200 kJ or 2%, without raising the heart rate or any observed adverse effects. The lack of effect of the enterocoated preparation suggests that a local action of capsaicin in the gastric mucosa is a prerequisite for exerting the thermogenic effect.

[Indexed for MEDLINE]

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