Associations of Green Tea and Rock Tea Consumption with Risk of Impaired Fasting Glucose and Impaired Glucose Tolerance in Chinese Men and Women

Abstract

ObjectiveTo explore the associations of green tea and rock tea consumption with risk of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT).MethodsA multistage, stratified, cluster, random-sampling method was used to select a representative sample from Fujian Province in China. In total, 4808 subjects without cardiovascular disease, hypertension, cancer, or pancreatic, liver, kidney, or gastrointestinal diseases were enrolled in the study. A standard questionnaire was used to gather data on tea (green, rock, and black) consumption and other relevant factors. The assessment of impaired glucose regulation (IGR) was using 75-g oral glucose tolerance test (OGTT), the diagnostic criteria of normal glucose tolerance was according to American Diabetes Association.ResultsGreen tea consumption was associated with a lower risk of IFG, while rock tea consumption was associated with a lower risk of IGT. The adjusted odds ratios for IFG for green tea consumption of <1, 1–15, 16–30, and >30 cups per week were 1.0 (reference), 0.42 (95% confidence intervals (CI) 0.27–0.65), 0.23 (95% CI, 0.12–0.46), and 0.41 (95% CI, 0.17–0.93), respectively. The adjusted odds ratios for IGT for rock tea consumption of <1, 1–15, 16–30, and >30 cups per week were 1.0 (reference), 0.69 (95% CI, 0.48–0.98), 0.59 (95% CI, 0.39–0.90), and 0.64 (95% CI, 0.43–0.97), respectively. A U-shaped association was observed, subjects who consumed 16–30 cups of green or rock tea per week having the lowest odds ratios for IFG or IGT.ConclusionsConsumption of green or rock tea may protect against the development of type 2 diabetes mellitus in Chinese men and women, particularly in those who drink 16–30 cups per week.

Antidiabetic Effects of Tea

“…Green tea consumption was associated with a lower risk of impaired fasting glucose (IFG), while oolong tea consumption was associated with a lower risk of impaired glucose tolerance (IGT). A U-shaped association was observed, subjects who consumed 16–30 cups of green and oolong tea per week had the lowest ORs for IFG and IGT, respectively [ 22 ], suggesting that green tea and oolong tea showed antidiabetic effects through different mechanisms. The chemical composition of teas varies with the degree of fermentation.…”

A risk‐score model for predicting risk of type 2 diabetes mellitus in a rural Chinese adult population: A cohort study with a 6‐year follow‐up

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Green tea catechins for well-being and therapy: prospects and opportunities

“…The results of a case-control study conducted in the People's Republic of China with 4,800 subjects indicated that the consumption of green tea possibly protects against the development of type 2 diabetes, particularly in those who drink 16-30 cups/wk. 40 A meta-analysis performed on 12 eligible studies found that daily tea consumption ($3 cups/d) was associated with a lower risk of type 2 diabetes, with a relative risk of 0.84 compared with that of the lowest consumption and non-tea-drinking groups. 41 A study on beverage consumption in 25,639 adults in the UK found that the consumption of sugar-sweetened beverages was associated with high risk of type 2 diabetes, independent of adiposity.…”