Cambridge Centre for Sport and Exercise Sciences, School of Psychology and Sport Science, Anglia Ruskin University, Cambridge CB1 1PT, UK.
Department for Health, University of Bath, Bath BA2 7AY, UK.
Nutrients. 2021 Feb 26;13(3):764. doi: 10.3390/nu13030764.
This study investigated the effect of decaffeinated green tea extract (dGTE), with or without antioxidant nutrients, on fat oxidation, body composition and cardio-metabolic health measures in overweight individuals engaged in regular exercise. Twenty-seven participants (20 females, 7 males; body mass: 77.5 ± 10.5 kg; body mass index: 27.4 ± 3.0 kg·m; peak oxygen uptake (O): 30.2 ± 5.8 mL·kg·min) were randomly assigned, in a double-blinded manner, either: dGTE (400 mg·d (-)-epigallocatechin-3-gallate (EGCG), = 9); a novel dGTE+ (400 mg·d EGCG, quercetin (50 mg·d) and α-lipoic acid (LA, 150 mg·d), = 9); or placebo (PL, = 9) for 8 weeks, whilst maintaining standardised, aerobic exercise. Fat oxidation ('FAT' and steady state exercise protocols), body composition, cardio-metabolic and blood measures (serum glucose, insulin, leptin, adiponectin, glycerol, free fatty acids, total cholesterol, high [HDL-c] and low-density lipoprotein cholesterol [LDL-c], triglycerides, liver enzymes and bilirubin) were assessed at baseline, week 4 and 8. Following 8 weeks of dGTE+, maximal fat oxidation (MFO) significantly improved from 154.4 ± 20.6 to 224.6 ± 23.2 mg·min ( = 0.009), along with a 22.5% increase in the exercise intensity at which fat oxidation was deemed negligible (FAT; 67.6 ± 3.6%O, = 0.003). Steady state exercise substrate utilisation also improved for dGTE+ only, with respiratory exchange ratio reducing from 0.94 ± 0.01 at week 4, to 0.89 ± 0.01 at week 8 ( = 0.004). This corresponded with a significant increase in the contribution of fat to energy expenditure for dGTE+ from 21.0 ± 4.1% at week 4, to 34.6 ± 4.7% at week 8 ( = 0.006). LDL-c was also lower (normalised fold change of -0.09 ± 0.06) for dGTE+ by week 8 ( = 0.038). No other significant effects were found in any group. Eight weeks of dGTE+ improved MFO and substrate utilisation during exercise, and lowered LDL-c. However, body composition and cardio-metabolic markers in healthy, overweight individuals who maintained regular physical activity were largely unaffected by dGTE.
本研究旨在探讨脱咖啡因绿茶提取物（dGTE）联合或不联合抗氧化营养素对进行规律运动的超重个体脂肪氧化、身体成分和心血管代谢健康指标的影响。27 名参与者（20 名女性，7 名男性；体重：77.5 ± 10.5kg；体重指数：27.4 ± 3.0kg·m；峰值摄氧量（O）：30.2 ± 5.8mL·kg·min）以双盲方式随机分为三组，分别给予：dGTE（400mg·d-1表没食子儿茶素没食子酸酯（EGCG），n = 9）；新型 dGTE+（400mg·d-1 EGCG、槲皮素（50mg·d）和α-硫辛酸（LA，150mg·d），n = 9）；或安慰剂（PL，n = 9），持续 8 周，同时保持标准的有氧运动。在基线、第 4 周和第 8 周评估脂肪氧化（“FAT”和稳态运动方案）、身体成分、心血管代谢和血液指标（血清葡萄糖、胰岛素、瘦素、脂联素、甘油、游离脂肪酸、总胆固醇、高密度脂蛋白胆固醇[HDL-c]和低密度脂蛋白胆固醇[LDL-c]、甘油三酯、肝酶和胆红素）。经过 8 周的 dGTE+治疗，最大脂肪氧化（MFO）从 154.4 ± 20.6mg·min 显著改善至 224.6 ± 23.2mg·min（p = 0.009），脂肪氧化被认为微不足道（FAT）的运动强度增加了 22.5%（67.6 ± 3.6%O，p = 0.003）。仅 dGTE+治疗后稳态运动底物利用率也得到改善，呼吸交换比从第 4 周的 0.94 ± 0.01 降低至第 8 周的 0.89 ± 0.01（p = 0.004）。这对应于 dGTE+组脂肪对能量消耗的贡献从第 4 周的 21.0 ± 4.1%显著增加到第 8 周的 34.6 ± 4.7%（p = 0.006）。第 8 周时，dGTE+组的 LDL-c 水平也降低（归一化倍数变化为-0.09 ± 0.06，p = 0.038）。在任何一组中均未发现其他显著影响。8 周的 dGTE+可改善运动期间的最大脂肪氧化和底物利用率，并降低 LDL-c。然而，对于保持规律体育活动的健康超重个体，dGTE 对身体成分和心血管代谢标志物的影响基本没有影响。
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