Oolong tea increases metabolic rate and fat oxidation in men.
Rumpler W, Seale J, Clevidence B, Judd J, Wiley E, Yamamoto S, Komatsu T, Sawaki T, Ishikura Y, Hosoda K.Beltsville Human Nutrition Research Center, Beltsville, MD 20705, USA. rumpler@bhnrc.ars.usda.govAbstract
According to traditional Chinese belief, oolong tea is effective in the control of body weight. Few controlled studies, however, have been conducted to measure the impact of tea on energy expenditure (EE) of humans. A randomized cross-over design was used to compare 24-h EE of 12 men consuming each of four treatments: 1) water, 2) full-strength tea (daily allotment brewed from 15 g of tea), 3) half-strength tea (brewed from 7.5 g tea) and 4) water containing 270 mg caffeine, equivalent to the concentration in the full-strength tea treatment. Subjects refrained from consuming caffeine or flavonoids for 4 d prior to the study. Tea was brewed each morning; beverages were consumed at room temperature as five 300 mL servings. Subjects received each treatment for 3 d; on the third day, EE was measured by indirect calorimetry in a room calorimeter. For the 3 d, subjects consumed a typical American diet. Energy content of the diet was tailored to each subject's needs as determined from a preliminary measure of 24-h EE by calorimetry. Relative to the water treatment, EE was significantly increased 2.9 and 3.4% for the full-strength tea and caffeinated water treatments, respectively. This increase over water alone represented an additional expenditure of 281 and 331 kJ/d for subjects treated with full-strength tea and caffeinated water, respectively. In addition, fat oxidation was significantly higher (12%) when subjects consumed the full-strength tea rather than water.
J Nutr. 2001 Nov;131(11):2848-52
Abstract
According to traditional Chinese belief, oolong tea is effective in the control of body weight. Few controlled studies, however, have been conducted to measure the impact of tea on energy expenditure (EE) of humans. A randomized cross-over design was used to compare 24-h EE of 12 men consuming each of four treatments: 1) water, 2) full-strength tea (daily allotment brewed from 15 g of tea), 3) half-strength tea (brewed from 7.5 g tea) and 4) water containing 270 mg caffeine, equivalent to the concentration in the full-strength tea treatment. Subjects refrained from consuming caffeine or flavonoids for 4 d prior to the study. Tea was brewed each morning; beverages were consumed at room temperature as five 300 mL servings. Subjects received each treatment for 3 d; on the third day, EE was measured by indirect calorimetry in a room calorimeter. For the 3 d, subjects consumed a typical American diet. Energy content of the diet was tailored to each subject's needs as determined from a preliminary measure of 24-h EE by calorimetry. Relative to the water treatment, EE was significantly increased 2.9 and 3.4% for the full-strength tea and caffeinated water treatments, respectively. This increase over water alone represented an additional expenditure of 281 and 331 kJ/d for subjects treated with full-strength tea and caffeinated water, respectively. In addition, fat oxidation was significantly higher (12%) when subjects consumed the full-strength tea rather than water.
J Nutr. 2001 Nov;131(11):2848-52
Oolong tea increases energy metabolism in Japanese females.
Komatsu T, Nakamori M, Komatsu K, Hosoda K, Okamura M, Toyama K, Ishikura Y, Sakai T, Kunii D, Yamamoto S.
Department of Applied Nutrition, The University of Tokushima School of Medicine, Tokushima, Japan.
Abstract
Oolong tea is a traditional Chinese tea that has long been believed to be beneficial to health such as decreasing body fat. We were interested in this assertion and tried to evaluate the effect of oolong tea on energy expenditure (EE) in comparison with green tea. The subjects were eleven healthy Japanese females (age 20+/-1 y; body mass index (BMI) 21.2+/-2.5 kg/m2) who each consumed of three treatments in a crossover design: 1) water, 2) oolong tea, 3) green tea. Resting energy expenditure (REE) and EE after the consumption of the test beverage for 120 min were measured using an indirect calorimeter. The cumulative increases of EE for 120 min were significantly increased 10% and 4% after the consumption of oolong tea and green tea, respectively. EE at 60 and 90 min were significantly higher after the consumption of oolong tea than that of water (P<0.05). In comparison with green tea, oolong tea contained approximately half the caffeine and epigallocatechin galate, while polymerized polyphenols were double. These results suggest that oolong tea increases EE by its polymerized polyphenols.
J Med Invest. 2003 Aug;50(3-4):170-5.
Beneficial effects of oolong tea consumption on diet-induced overweight and obese subjects.
School of Traditional Chinese Materia Medicine, Shenyang Pharmaceutical University, Shenyang, 110016, China.
Abstract
OBJECTIVE: To determine the anti-obesity effects of oolong tea on diet-induced overweight or obesity.
METHODS: A total of 8 g of oolong tea a day for 6 weeks was ingested by 102 diet-induced overweight or obese subjects. The body fat level of the subjects was determined at the same time by taking body weight, height and waist measurements. The thickness of the subcutaneous fat layer was also determined on the abdomen 3 cm to the right of the navel by the ultrasonic echo method. On the other hand, effects of oolong tea ingestion on plasma triglyceride (TG) and total cholesterol (TC) were determined. Inhibitions of pancreatic lipase by oolong tea extract and catechins in vitro were also determined.
RESULTS: A total of 70% of the severely obese subjects did show a decrease of more than 1 kg in body weight, including 22% who lost more than 3 kg. Similarly, 64% of the obese subjects and 66% of the overweight subjects lost more than 1 kg during the experiment, and the subcutaneous fat content decreased in 12% of the subjects. The correlation between weight loss and subcutaneous fat decrease in men (r=0.055) was obviously lower than that in women (r=0.440, P<0.01). Body weight loss was signifificantly related to the decrease of the waist size in men (r=0.730, P<0.01) and women (r=0.480, P<0.01). Also, the correlation between subcutaneous fat reduction and decreased waist size was signifificant in women (r=0.554, P<0.01), but not in men (r=0.050, P>0.05). Moreover, the plasma levels of TG and TC of the subjects with hyperlipidemia were remarkably decreased after ingesting oolong tea for 6 weeks. In vitro assays for the inhibition of pancreatic lipase by oolong tea extract and catechins suggest that the mechanism for oolong tea to prevent hyperlipidemia may be related to the regulative action of oolong tea catechins in lipoprotein activity.
CONCLUSIONS: Oolong tea could decrease body fat content and reduce body weight through improving lipid metabolism. Chronic consumption of oolong tea may prevent against obesity.
Chin J Integr Med. 2009 Feb;15(1):34-41. Epub 2009 Mar 7
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