Effects of black and green tea consumption on blood glucose levels in non-obese elderly men and women from Mediterranean Islands (MEDIS epidemiological study)

Polychronopoulos, Evangelos; Zeimbekis, Akis; Kastorini, Christina-Maria; Papairakleous, Natassa; Vlachou, Ioanna; Bountziouka, Vassiliki

doi:10.1007/s00394-007-0690-7

Cited by 58 publications

(48 citation statements)

References 26 publications

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“…One study observed a borderline inverse association between magnesium intake and risk of type 2 diabetes. However, magnesium did not explain the relation between coffee and type 2 diabetes in our study, similar to other studies [30,[34][35][36]. In our study up to three cups of coffee was associated with higher blood pressure, but more than four cups of coffee was associated with a lowered blood pressure.…”

Section: Discussionsupporting

confidence: 81%

“…Although we could not differentiate between black and green tea, an estimated 95% of the total tea consumption is black tea in the Netherlands [25]. Recently, a study reported that both black and green tea lower blood glucose concentrations [34]. Combined with our results, it seems likely that the association between tea consumption and type 2 diabetes is not solely due to consumption of green tea.…”

Section: Discussionsupporting

confidence: 46%

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Coffee and tea consumption and risk of type 2 diabetes

et al. 2009

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Aims/hypothesis The aim of this study was to examine the association of consumption of coffee and tea, separately and in total, with risk of type 2 diabetes and which factors mediate these relations. Methods This research was conducted as part of the Dutch Contribution to the European Prospective Investigation into Cancer and Nutrition, which involves a prospective cohort of 40,011 participants with a mean follow-up of 10 years. A validated food-frequency questionnaire was used to assess coffee and tea consumption and other lifestyle and dietary factors. The main outcome was verified incidence of type 2 diabetes. Blood pressure, caffeine, magnesium and potassium were examined as possible mediating factors. Results During follow-up, 918 incident cases of type 2 diabetes were documented. After adjustment for potential confounders, coffee and tea consumption were both inversely associated with type 2 diabetes, with hazard ratios of 0.77 (95% CI 0.63-0.95) for 4.1-6.0 cups of coffee per day (p for trend=0.033) and 0.63 (95% CI: 0.47-0.86) for >5.0 cups of tea per day (p for trend=0.002). Total daily consumption of at least three cups of coffee and/or tea reduced the risk of type 2 diabetes by approximately 42%. Adjusting for blood pressure, magnesium, potassium and caffeine did not attenuate the associations. Conclusions/interpretation Drinking coffee or tea is associated with a lowered risk of type 2 diabetes, which cannot be explained by magnesium, potassium, caffeine or blood pressure effects. Total consumption of at least three cups of coffee or tea per day may lower the risk of type 2 diabetes.

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Section: Discussionsupporting

confidence: 81%

Section: Discussionsupporting

confidence: 46%

Coffee and tea consumption and risk of type 2 diabetes

et al. 2009

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“…Seven studies were excluded because they were other design types. 24,25,[35][36][37][38][39] A study by Mackenzie et al 40 was excluded because some participants had diabetes at baseline. Two articles were excluded because they did not provide 95% CI or data to calculate (Fig.…”

Section: Study Selection and Data Extractionmentioning

confidence: 99%

“…22 Another study provided evidence that green tea promoted glucose metabolism in healthy humans and produced an antihyperglycemic effect in diabetic mice. 24 A population-based, case-control study by Polychronopoulos et al 25 reported that tea consumption could reduce levels of fasting blood glucose in nonobese elderly people.…”

Section: Introductionmentioning

confidence: 99%

“…To our knowledge, several epidemiologic studies [25][26][27][28][29][30][31][32][33][34] have been performed to investigate the association of tea consumption with type 2 diabetes; however, the results of these studies were not entirely consistent: some studies showed that tea consumption might reduce the risk of type 2 diabetes, 25,28,29,[32][33][34] whereas others found nonsignificant relationships between the two. 26,27,30,31 Because the relationship between tea consumption and risk of type 2 diabetes is still equivocal, we conducted this meta-analysis to further clarify this association based on the studies from the United States, Europe, and Asian countries.…”

Section: Introductionmentioning

confidence: 99%

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Tea Consumption and Risk of Type 2 Diabetes: A Meta-Analysis of Cohort Studies

Jing

Han

et al. 2009

J GEN INTERN MED

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BACKGROUND: Tea consumption has been extensively studied in relation to various diseases, several epidemiologic studies have been performed to investigate the association of tea consumption with type 2 diabetes; however, the results of these studies were not entirely consistent. OBJECTIVE:To conduct a meta-analysis of studies that assessed the association of tea consumption and the risk of type 2 diabetes. RESEARCH DESIGN AND METHODS:We performed a systematic literature search through November 2008 in PUBMED, MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews. The search was limited to Englishlanguage studies. Studies were excluded if they were type 1 diabetes, animal studies. Nine cohort studies were identified by two authors, and summary relative risks (RRs) were calculated using a random-effects model. RESULTS:We identified nine cohort studies, including 324,141 participants and 11,400 incident cases of type 2 diabetes with follow-up ranging from 5 to 18 years. The summary adjusted RR did not show that tea consumption was associated with a reduced type 2 diabetes risk (RR, 0.96; 95% confidence interval (CI), 0.92-1.01). Evidence from the results of our stratified analyses revealed that tea consumption ≥4 cups per day (RR, 0.8; 95% CI, 0.7-0.93) might play a role in the prevention of type 2 diabetes. However, no statistically significant association was observed for sex and the follow-up durations stratified between tea consumption and type 2 diabetes. CONCLUSIONS:This meta-analysis indicates that tea consumption ≥4 cups per day may lower the risk of type 2 diabetes.KEY WORDS: type 2 diabetes; tea; meta-analysis.

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