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Human and Clinical Nutrition
Abbreviations: EGCG, epigallocatechin gallate
Morbidity from overweight and obesity is increasing, leading to numerous health problems. Prolonged excess energy intake and decreased energy expenditure lead to body fat accumulation. Obesity, especially visceral obesity, carries a strong risk of some related CVD and metabolic diseases, such as the metabolic syndrome, hyperlipidaemia, hypertension and diabetes mellitus(1). Lifestyle modification, especially changing dietary habits, plays an important role in the management of obesity. Both increasing energy expenditure and decreasing energy intake may stimulate weight loss and improvement of body composition.
Green tea is a popular and widely consumed beverage around the world. Green tea-derived polyphenols such as epigallocatechin gallate (EGCG), the most abundant catechin in tea, have been reported to produce physiological effects, including antioxidative, anticancer, anti-obesity and hypolipidaemic effects. Epidemiological studies in Taiwan show an inverse relationship between habitual tea consumption and body fat distribution(2,3). Human and animal studies have explored the mechanism by which green tea catechins may be beneficial for the prevention or treatment of obesity. EGCG may decrease energy intake by reducing food intake, interrupting lipid emulsification and absorption, and increasing energy expenditure via thermogenesis, fat oxidation and faecal lipid excretion, and this so far only has been shown in animal studies. However, information from human studies is still limited(4).
Inulin-type fructans are a linear polydisperse carbohydrate material consisting mainly of [beta]-(2 [arrow left] 1) fructosyl-fructose linkages. They resist hydrolysis by human digestive enzymes; thus, they are recognised as a kind of non-digestive oligosaccharide(5). Inulins are now widely used as an ingredient of functional foods for its properties as dietary fibre and prebiotics. A series of studies has demonstrated that inulin affects lipid homeostasis and metabolism, and body weight, though the mechanisms remain unclear(6,7). Therefore, the present study was designed to investigate whether habitual consumption of green tea beverages containing high doses of catechins in combination with inulin can produce weight loss and fat redistribution in overweight subjects.
Materials and methods
Preparation of green tea
For the experimental group, 28 g of green tea leaves (Camellia sinensis) were extracted...