A Green Tea Extract High in Catechins Reduces Body Fat and Cardiovascular Risks in Humans

Abstract

NAGAO, TOMONORI, TADASHI HASE, AND ICHIRO TOKIMITSU. A green tea extract high in catechins reduces body fat and cardiovascular risks in humans. Obesity. 2007; 15:1473-1483. Objective: The body fat reducing effect and reduction of risks for cardiovascular disease by a green tea extract (GTE) high in catechins was investigated in humans with typical lifestyles. Research Methods and Procedures: Japanese women and men with visceral fat-type obesity were recruited for the trial. After a 2-week diet run-in period, a 12-week doubleblind parallel multicenter trial was performed, in which the subjects ingested green tea containing 583 mg of catechins (catechin group) or 96 mg of catechins (control group) per day. Randomization was stratified by gender and body mass index at each medical institution. The subjects were instructed to maintain their usual dietary intake and normal physical activity. Results: Data were analyzed using per-protocol samples of 240 subjects (catechin group; n ϭ 123, control group; n ϭ 117). Decreases in body weight, body mass index, body fat ratio, body fat mass, waist circumference, hip circumference, visceral fat area, and subcutaneous fat area were found to be greater in the catechin group than in the control group. A greater decrease in systolic blood pressure (SBP) was found in the catechin group compared with the control group for subjects whose initial SBP was 130 mm Hg or higher. Low-density lipoprotein (LDL) cholesterol was also decreased to a greater extent in the catechin group. No adverse effect was found. Discussion: The continuous ingestion of a GTE high in catechins led to a reduction in body fat, SBP, and LDL cholesterol, suggesting that the ingestion of such an extract contributes to a decrease in obesity and cardiovascular disease risks.

The effects of green tea on weight loss and weight maintenance: a meta-analysis

“…In all but one study, 17 subjects were randomly assigned to two conditions, with seven studies 10,15-20 using a true placebo group and the remaining four studies [11][12][13][14] comparing a high with a low dose of an EGCG-caffeine mixture.…”

“…[10][11][12][13][14][15][16][17] On the other hand, studies with Caucasian subjects reported mixed results. [18][19][20] Moreover, the amount of regular caffeine intake may also influence the effectiveness of catechins.…”

White tea (Camellia sinensis) extract reduces oxidative stress and triacylglycerols in obese mice

“…Some authors found reduction of cholesterol in mice (KIM et al, 2009;RICHARD et al, 2009), while others did not find any difference (FARDET et al, 2008;ZHENG et al, 2004). The controversy also exists in clinical studies showing beneficial (HSU et al, 2008;NAGAO;HASE;TOKIMITSU, 2007) or no effect on blood cholesterol (MAKI et al, 2009) after green tea supplementation. Since antioxidant agents such as green and white tea do affect quantitatively the circulating lipoproteins and cholesterol, it is not surprising that they did not affect blood concentration of cholesterol.…”

“…These authors also observed increased excretion of lipids after ingestion of a mixture of these teas. Although some studies have not shown the effect of catechins on the reduction of triacylglycerols (KIM et al, 2009;NAGAO;HASE;TOKIMITSU, 2007), the available literature on green tea and its catechins shows that it can improve the lipid profile by decreasing the luminal hydrolysis of lipids and thereby reduce its intestinal absorption (BABU; LIU, 2008;KOO;NOH, 2007). Furthermore, it has been reported that catechins regulate the expression of hepatic LDL receptors modulating the lipid synthesis, excretion, and intracellular processing (BABU; LIU, 2008;KOO;NOH, 2007).…”

Effects of a beverage rich in (poly)phenols on established and novel risk markers for vascular disease in medically uncomplicated overweight or obese subjects: A four week randomized placebo-controlled trial

“…Green tea extracts in Japanese subjects with visceral obesity led to reductions in systolic blood pressure however the CV risk status of the included subjects is not clear (27). Conversely, increases in systolic blood pressure were seen with a combination of vitamin c and grape-seed polyphenols in a study of treated hypertensives (28).…”