Health effects of green tea catechins in overweight and obese men: a randomised controlled cross-over trial

Abstract

Regular consumption of green tea may be cardioprotective. In the present study we investigated the health effects of dietary supplementation with green tea catechins and the potential modifying effect of the catechol-O-methyltransferase (COMT) Val/Met genotype. Subjects (sedentary males, aged 40-69 years, with BMI $ 28 and # 38 kg/m 2 ) were randomly assigned to consume decaffeinated green tea extract (DGT; 530 mg containing about 400 mg total catechins/capsule, twice daily) and placebo in a complete cross-over design. Ambulatory blood pressure and biomarkers of metabolic function (cholesterol, TAG, glucose and insulin) were measured at weeks 0 and 6. Although a marked increase in the concentration of plasma epigallocatechin gallate (EGCG), urinary epigallocatechin (EGC) and urinary 4 0 -O-methyl EGC was found after DGT treatment, no effect on blood pressure or biomarkers of metabolic function was observed. However, a period £ treatment interaction (P, 0·05) was detected for body-weight change. Despite a similar increase in estimated energy intake during intervention period 1, body weight decreased by 0·64 (SD 2·2) kg and increased by 0·53 (SD 1·9) kg in the DGT and placebo groups, respectively (P¼0·025), suggesting a protective effect of green tea catechins on weight gain. Additionally, the COMT Val/Met genotype influenced urinary accumulation of EGC and 4 0 -O-methyl EGC (P, 0·01). Mean concentrations were lower in individuals homozygous for the high-activity G-allele, possibly reflecting increased metabolic flux and a more rapid conversion to downstream metabolic species, compared with individuals carrying at least one copy of the low-activity A-allele. Additional studies are needed to confirm these findings and further explore the modifying effect of genotype.

Limited Sampling Estimates of Epigallocatechin Gallate Exposures in Cirrhotic and Noncirrhotic Patients With Hepatitis C After Single Oral Doses of Green Tea Extract

“…28 However, chronic moderate to high dose daily GTE and EGCG use in healthy human volunteers was not shown to cause severe adverse effects or impair liver function. [29][30][31][32] Prior pharmacokinetic studies have established peak blood concentrations and exposures of EGCG associated with its safety and tolerability in healthy subjects. [30][31][32][33][34] In a study by Chow et al, following a single 800mg dose of EGCG in five healthy volunteers, AUC (min·µg/ml) ±SD was 167.1 ± 57.0, C max (ng/mL) was 438.5 ± 28.4 and t 1/2 (min) was 114.0 ± 33.3.…”

“…[29][30][31][32] Prior pharmacokinetic studies have established peak blood concentrations and exposures of EGCG associated with its safety and tolerability in healthy subjects. [30][31][32][33][34] In a study by Chow et al, following a single 800mg dose of EGCG in five healthy volunteers, AUC (min·µg/ml) ±SD was 167.1 ± 57.0, C max (ng/mL) was 438.5 ± 28.4 and t 1/2 (min) was 114.0 ± 33.3. 35 In a multi-dose study by Chow et al, volunteers were randomly assigned to receive one of the five treatments for 4 weeks: 800 mg EGCG once/day, 400 mg EGCG twice/day, 800 mg EGCG as Polyphenon E once/day, 400 mg EGCG as Polyphenon E twice/day, or a placebo once/day (8 subjects/group).…”

Pengembangan pangan fungsional berbasis tepung okara dan tepung beras hitam (Oryza sativa L. indica) sebagai makanan selingan bagi remaja obesitas

“…Penurunan stres oksidatif pada obesitas dapat dilakukan dengan mengonsumsi makanan yang tinggi antioksidan seperti buah-buahan, sayur-sayuran, bijibijian, kacang-kacangan, ikan, minyak zaitun, susu fermentasi, teh dan anggur merah. 18,19 Kadar antioksidan yang terdapat pada produk makanan selingan snack bar dalam penelitian ini cukup tinggi yaitu, pada formula I 208,35 mg/L GAEAC, formula II sebesar 218,15 mg/L GAEAC dan formula III sebesar 201,05 mg/L GAEAC.…”

The anti-obesity effects of EGCG in relation to oxidative stress and air-pollution in China

“…Compared with the control high fat (HF) diet group, the GTP supplementation increased lean mass, bone mineral density and strength, and decreased pro-inflammatory cytokines and IGF-1 55 . Furthermore, a decaffeinated green tea extract consisting of 530 mg total, containing 400 mg total catechins/capsule, was administered twice daily and was shown to decrease body weight versus placebo groups suggesting a weight gain protective effect 56 . Direct decreased body weight by green tea catechins such as EGCG, in particular adipose tissue is a direct result of increased lipolysis, and decreased apipogenesis/lipogenesis, which may be a beneficial effect to reduce obesity development via increased systemic inflammation by inhalation of air-pollution and in combination with a rapidly changing diet in urbanized mainland Chinese.…”