Short-term weight-centric effects of tea or tea extract in patients with metabolic syndrome: a meta-analysis of randomized controlled trials.

X Zhong,Y Liu,X Ma,Q Chen,J He,R Wang,T Zhang,Z Jin,Y Qin,X Zhang,X Wei

doi:10.1038/nutd.2015.10

X Zhong, Y Liu + Show 9 more

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https://doi.org/10.1038/nutd.2015.10

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Abstract

To evaluate the weight-centric effect of tea or tea extract in participants with metabolic syndrome (MetS), we performed electronic searches in PubMed, EmBase and the Cochrane Library to identify eligible randomized controlled trials (RCTs) comparing tea or tea extract vs a control group. A direct meta-analysis using random-effects model was conducted to pool the standardized mean difference regarding body mass index (BMI), body weight and waist circumference. Study quality was assessed by using the Jadad scale. Pre-specified subgroup and sensitivity analyses were conducted to explore potential heterogeneity. A total of five RCTs involving 338 adult individuals were included. Given the high heterogeneity observed in the overall pooled analysis, we separated the included subjects into two subgroups. Ingestion of tea or tea extract significantly reduced BMI (subgroup 1: −1.60, 95% confidence interval (CI), −2.05 to −1.14; subgroup 2: −0.40, 95% CI, −0.69 to −0.12) and body weight (subgroup 1: −4.14, 95% CI, −4.85 to −3.43; subgroup 2: −0.35, 95% CI, −0.68 to −0.02). This meta-analysis suggests that tea or tea extract has favorable weight-centric effects in MetS patients. Additional large RCTs specifically designed to evaluate the effect on anthropometric measurements are needed to further confirm these findings.

Highlights

Metabolic syndrome (MetS) is usually diagnosed by a cooccurrence of three out of five of the following medical conditions: abdominal obesity, elevated glucose, elevated blood pressures, high triglycerides and low high-density lipoproteincholesterol levels.[1,2] The International Diabetes Federation estimates that one-quarter of the world's adult population has MetS.[3]In the last decade, MetS has been increasing to the point of being regarded as an epidemic.[1]
The following information was extracted from each eligible study: (i) first author’s surname, (ii) publication year; (iii) sample size; (iv) study treatment duration; (v) baseline characteristics; (vi) type of diet, lifestyle and exercise status; (vii) study treatment description, and (viii) parameters of end points
Pharmacological agents that deal with obesity, diabetes, hypertension and dyslipidemia are usually administered in combination among MetS patients

Summary

Introduction

Metabolic syndrome (MetS) is usually diagnosed by a cooccurrence of three out of five of the following medical conditions: abdominal obesity, elevated glucose, elevated blood pressures, high triglycerides and low high-density lipoproteincholesterol levels.[1,2] The International Diabetes Federation estimates that one-quarter of the world's adult population has MetS.[3]In the last decade, MetS has been increasing to the point of being regarded as an epidemic.[1]. Scheen and Van Gaal[4] even proposed a shift from a glucocentric to a weight-centric management for patients with type 2 diabetes. With a modest weight loss, both hypertensive individuals and subjects at risk of developing hypertension can observe a significant reduction in the blood pressure.[5] a weight loss of as small as 5–10% of body weight can significantly reduce triglycerides and increase high-density lipoprotein-cholesterol.[6] this weight loss appears specific to the weight but results in an improvement of many obesity-related conditions, including various abnormal components of the MetS and development of diabetes.[7]

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