1.
Effect of green tea extract on lipid profile in patients with type 2 diabetes mellitus: A systematic review and meta-analysis.
Asbaghi, O, Fouladvand, F, Moradi, S, Ashtary-Larky, D, Choghakhori, R, Abbasnezhad, A
Diabetes & metabolic syndrome. 2020;(4):293-301
Abstract
BACKGROUND Previous studies have indicated controversial results regarding the efficacy of green tea extract (GTE) in improving the lipid profile of type 2 diabetes mellitus (T2DM) patients. We aimed to conduct a systematic review and meta-analysis to pool data from randomized controlled trials (RCTs). METHODS A systematic search was performed in Web of Science, PubMed, and Scopus databases, without any language and time restriction until August 2019, to retrieve the RCTs which examined the effects of GTE on serum concentrations of high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglyceride (TG) or total cholesterol (TC) in T2DM patients. Meta-analyses were carried out using a random effects model. I2 index was used to evaluate the heterogeneity. RESULTS Initial search yielded 780 publications. Of these, seven studies were eligible. The supplementary intake of GTE improved lipid profile by reducing serum TG concentrations in patients with T2DM. Meanwhile, subgroup analyses based on duration of interventions (≤8 and > 8 weeks) and intervention dosage (≤800 and > 800 mg/day) showed that the GTE supplementation longer than 8 weeks and in doses >800 mg/day resulted in a significant decrease in serum TG concentrations. Furthermore, intervention longer than 8 weeks with doses lower than 800 mg/day resulted in a significant reduction in serum TC concentrations. CONCLUSION In conclusion, present systematic review and meta-analysis revealed that the supplementary intake of GTE may improve lipid profile by reducing serum concentrations of TG in patients with T2DM. Furthermore, the results of our stratified analyses suggested that long-term GTE intervention may reduce serum concentrations of TG and TC.
2.
Effects of tea consumption on metabolic syndrome: A systematic review and meta-analysis of randomized clinical trials.
Liu, W, Wan, C, Huang, Y, Li, M
Phytotherapy research : PTR. 2020;(11):2857-2866
Abstract
The metabolic syndrome (MetS) is one of the major health hazards and an epidemic worldwide. There is no known best remedy has been defined yet. In the current investigation, we designed a meta-analysis of randomized clinical trials (RCTs) to evaluate the beneficial effects of tea consumption in alleviating metabolic syndromes. Herein, we accumulated the relevant literature available on PubMed and EMBASE databases from January, 2000 to August, 2019. RCTs bearing impact factor of at least 1 or more were studied for the effect of tea consumption on MetS. This meta-analysis suggested that tea consumption has beneficial effects on diastolic blood pressure (DBP), and this finding was characterized of all types of tea in the current study and also for body mass index (BMI) value. Furthermore, this analysis also found that black tea consumption has protective effects on systolic SBP, green tea reduces the incidence of diabetes and lower the level of low-density lipoprotein (LDL) cholesterol. These functions required BMI value at least 28 or higher. The meta data led us to conclude that tea consumption have protective effects on MetS, however, different types of tea might have different protective mechanisms on MetS, but, exact mechanisms are not yet clear and needs to be explored.
3.
Efficacy of tea catechin-rich beverages to reduce abdominal adiposity and metabolic syndrome risks in obese and overweight subjects: a pooled analysis of 6 human trials.
Hibi, M, Takase, H, Iwasaki, M, Osaki, N, Katsuragi, Y
Nutrition research (New York, N.Y.). 2018;:1-10
Abstract
This post hoc pooled analysis assessed the effectiveness of green tea catechins (GTC) to reduce the risk of metabolic syndrome (MetS) associated with abdominal fat reduction, because previous findings are unclear. Data were pooled from six human trials (n=921, 505 men) comparing the effects of GTC-containing beverages (540-588 mg GTC/beverage) and a placebo beverage. Outcome measures were abdominal fat [total fat area (TFA), visceral fat area (VFA), subcutaneous fat area (SFA)], and MetS risk. We estimated mean changes from baseline and calculated confidence intervals (CI) to assess reductions in abdominal fat accumulation and MetS improvement. Subclass analyses were performed by classifying subjects as Pre-MetS or MetS at trial initiation. Additional subclass analyses were performed with Pre-MetS and MetS subjects further stratified according to whether GTC intake reduced TFA, VFA, or SFA. Consumption of GTC-containing beverages for 12 weeks significantly reduced TFA (-17.7cm2, 95%CI: -20.9 to -14.4), VFA (-7.5cm2, 95%CI: -9.3 to -5.7), SFA (-10.2cm2, 95%CI: -12.5 to -7.8), body weight, body mass index, and waist circumference; and improved blood pressure. Subclass analyses of Pre-MetS and MetS subjects showed improved MetS in the GTC group [odds ratio (OR), 1.67; 95%CI: 1.08-2.57]. The ORs for improved MetS in the TFA- and VFA-reduced groups were 2.79 (95%CI: 1.28-6.09) and 4.36 (95%CI: 2.03-9.39), respectively. Continual consumption of GTC-containing beverages reduced abdominal fat and improved MetS, suggesting its potential to prevent diabetes and cardiovascular disease. Additional large-scale intervention trials are needed to evaluate the effects of GTC on the risk of MetS in high-risk populations.