Kosen-cha, a Polymerized Catechin-Rich Green Tea, as a Potential Functional Beverage for the Reduction of Body Weight and Cardiovascular Risk Factors: A Pilot Study in Obese Patients

Abstract

Previous studies have shown that green tea catechins (GTCs) have beneficial effects on obesity and metabolic syndromes. In this study, we prepared kosen-cha from green tea using high pressure extraction, to reduce the astringent taste of the green tea. We identified a large quantity of polymerized GTCs in kosen-cha. To investigate the effects of kosen-cha containing polymerized GTCs in obese Japanese patients, we designed an open-label pilot study in which 6 obese subjects (body mass index (BMI) >25 kg/m 2) were administered kosen-cha (5 g/L/d) for 12 weeks. Body composition, serum lipids, insulin resistance, vascular functions, and cardiac hypertrophy were measured before and 12 weeks after kosen-cha administration. Kosen-cha showed no significant adverse effects on the patients. Body weights, BMI, waist circumferences, serum triglyceride (TG) levels, and homeostasis model assessment as an index of insulin resistance (HOMA-IR) levels were significantly decreased after the 12 weeks of administration. Flow-mediated dilation (FMD) (p 0.0214), brachial-ankle pulse wave velocity (baPWV)(p 0.0141), left ventricular mass indexes (p 0.0120), and plasma brain natriuretic peptide (BNP) (p 0.0144) were significantly improved. Overall, kosen-cha reduced obesity and improved insulin resistance, vascular function, and cardiac hypertrophy, indicating its preventive potential in obesity and metabolic syndrome.

A Randomized Placebo-controlled, Double-blind Study of Kosen-cha, a Polymerized Catechin-rich Green Tea, for Obesity in Pre-obese Japanese Subjects

“…17) Our pilot study showed that Kosen-cha significantly reduced the body weight and BMI of overweight patients. 15) However, in the present study, body weight, BMI, waist circumference, blood glucose, LDL-C, and TG remained unchanged between the two groups. The BMI of the all subjects enrolled in the pilot study was > 30, and the consumption of Kosen-cha reduced their body weight over 12-week administration.…”

“…Beverages (Kosen-cha and Placebo) Kosen-cha, which was prepared from green tea leaves processed at high temperature and pressure, was supplied by SUNDIA Co., Ltd (Tokyo, Japan). 15) Barley tea was used as the placebo because it contains no polymerized green tea catechins but has a similar color. Both Kosen-cha and the placebo were provided to the subjects as teabags containing 1.7 g of tea leaves in each bag; the subjects prepared tea each morning by adding 1,000 mL boiling water to the 3 teabags and drank the tea thrice daily with meals for 12 weeks.…”

“…13,14) In a pilot study, we reported that Kosen-cha reduced the body weight of patients with metabolic syndrome. 15) However, whether it reduces the body weight of pre-obese subjects is yet to be elu-…”

Dietary Flavonoids and Insulin Signaling in Diabetes and Obesity

“…An improved HOMA-IR and insulin sensitivity together with an increased fat oxidation was reported. Similarly, Kosen-cha (a polymerized catechin-green tea, 1 L/day containing 1430 mg polyphenols), a pecan-rich diet (15% of total calories) and pomegranate juice (500 mL/day containing 842.5 mg polyphenols) reduced the insulin resistance (HOMA-IR) after the intervention [97][98][99]. This effect was accompanied by reduced values of insulinemia, glycemia and homeostasis model assessment of β-cell function (HOMA-B), and improved blood pressure (BP) and lipid profile.…”

Determination of Phenolic Compounds in Beverages by Three-Flow Channel Isocratic HPLC with Electrochemical Detections Using a Column-Switching Technique

“…[1][2][3][4][5] Currently, the protective biological activities of phenolic compounds are focused on effects such as: antiallergic, anti-biotic, anti-carcinogenic, anti-inflammatory, anti-oxidant, anti-thrombotic, anti-ulcerative, and vasorelaxing. [6][7][8][9][10][11][12][13][14][15] Thus, to estimate the qualities and health-promoting properties of beverages, analytical methods for determining phenolic compounds will play an important role. 15) As such, the quantitative analysis of phenolic compounds in beverages is challenging, because it requires a selective and sensitive detection method to obtain accurate and precise results without affecting the matrices derived from the samples.…”