***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND Green tea consumption has been associated with favorable changes in body weight and obesity-related hormones , although it is not known whether these changes result from green tea polyphenols or caffeine . OBJECTIVE We examined the impact of decaffeinated green tea extract ( GTE ) containing 843 mg of (-)-epigallocatechin-3-gallate on anthropometric variables , obesity-associated hormones , and glucose homeostasis . METHODS The Minnesota Green Tea Trial was a 12-mo r and omized , double-blind , placebo-controlled clinical trial of 937 healthy postmenopausal women assigned to either decaffeinated GTE ( 1315 mg total catechins/d ) or a placebo  , stratified by catechol-O-methyltransferase ( COMT ) genotype . This study was conducted in a subset of 237 overweight and obese participants [ body mass index ( BMI ) ≥25 kg/m(2 ) ] . RESULTS No changes in energy intake , body weight , BMI , or waist circumference ( WC ) were observed over 12 mo in women taking GTE ( n = 117 ) or placebo ( n = 120 ) . No differences were seen in circulating leptin , ghrelin , adiponectin , or glucose concentrations at month 12 . Participants r and omly assigned to GTE with baseline insulin ≥10 μIU/mL ( n = 23 ) had a decrease in fasting serum insulin from baseline to month 12 ( -1.43 ± 0.59 μIU/mL ) , whereas those r and omly assigned to placebo with baseline insulin ≥10 μIU/mL ( n = 19 ) had an increase in insulin over 12 mo ( 0.55 ± 0.64 μIU/mL , P < 0.01 ) . Participants with the homozygous high-activity ( G/G ) form of COMT had significantly lower adiponectin ( 5.97 ± 0.50 compared with 7.58 ± 0.53 μg/mL , P = 0.03 ) and greater insulin concentrations ( 7.63 ± 0.53 compared with 6.18 ± 0.36 μIU/mL , P = 0.02 ) at month 12 compared with those with the low-activity ( A/A ) genotype , regardless of treatment group . CONCLUSIONS Decaffeinated GTE was not associated with reductions in body weight , BMI , or WC and did not alter energy intake or mean hormone concentrations in healthy postmenopausal women over 12 mo . GTE decreased fasting insulin concentrations in those with elevated baseline fasting concentrations . The high-activity form of the COMT enzyme may be associated with elevations in insulin and a reduction in adiponectin concentrations over time . This trial was registered at http://www . clinical trials.gov as NCT00917735 Background —Epidemiological studies suggest that tea consumption decreases cardiovascular risk , but the mechanisms of benefit remain undefined . Endothelial dysfunction has been associated with coronary artery disease and increased oxidative stress . Some antioxidants have been shown to reverse endothelial dysfunction , and tea contains antioxidant flavonoids . Methods and Results —To test the hypothesis that tea consumption will reverse endothelial dysfunction , we r and omized 66 patients with proven coronary artery disease to consume black tea and water in a crossover design . Short-term effects were examined 2 hours after consumption of 450 mL tea or water . Long-term effects were examined after consumption of 900 mL tea or water daily for 4 weeks . Vasomotor function of the brachial artery was examined at baseline and after each intervention with vascular ultrasound .  Fifty patients completed the protocol and had technically suitable ultrasound measurements . Both short- and long-term tea consumption improved endothelium- dependent flow-mediated dilation of the brachial artery , whereas consumption of water had no effect ( P < 0.001 by repeated- measures ANOVA ) . Tea consumption had no effect on endothelium-independent nitroglycerin-induced dilation . An equivalent oral dose of caffeine ( 200 mg ) had no short-term effect on flow-mediated dilation . Plasma flavonoids increased after short- and long-term tea consumption . Conclusions —Short- and long-term black tea consumption reverses endothelial vasomotor dysfunction in patients with coronary artery disease . This finding may partly explain the association between tea intake and decreased cardiovascular disease events BACKGROUND Green tea is one of the most popular beverages in the world . It is believed to have beneficial effects in the prevention and treatment of many diseases , one of which is type 2 diabetes . The aim of the study is to examine the effect of a decaffeinated green tea extract ( GTE ) providing a daily dose of 856 mg of epigallocatechin gallate ( EGCG ) on obese individuals with type 2 diabetes . MATERIAL S AND METHODS The clinical trial was a r and omized , double-blind , placebo-controlled clinical trial conducted from December 2007 through November 2008 . The subjects were r and omly assigned to either receive 1,500 mg of a decaffeinated GTE or placebo daily for 16 weeks . Sixty-eight of 80 subjects , ages 20 - 65 years with BMI > 25 kg/m2 and type 2 diabetes for more than one year , completed this study .  Homeostasis model assessment for insulin resistance ( HOMA-IR ) was used as the major outcome measurement . At baseline and after 16 weeks of treatment , anthropometric measurements , fasting glucose , hemoglobin A1C percent ( HbA1C ) , hormone peptides , and plasma lipoproteins were measured from both groups . RESULTS No statistically significant differences were detected between the decaffeinated GTE and placebo groups in any measured variable . A statistically significant within-group 0.4-percent reduction in HbA1C ( from 8.4 to 8.0 % ) was observed after GTE treatment compared to baseline . Within-group comparison also revealed that the GTE group had significant reductions in waist circumference ( WC ) , HOMA-IR index , and insulin level , and a significant increase in the level of ghrelin . Within-group comparison of those in the placebo group showed a significant increase in the level of ghrelin . CONCLUSIONS This study found no statistical difference in any measured variable between the decaffeinated GTE and placebo groups ; however , there were some statistically significant within-group changes detected . More research is required to determine whether a decaffeinated GTE st and ardized for EGCG content will provide any clinical benefits in obese individuals with type 2 diabetes . Clinical Trial Registration NO : NCT00567905 AIMS Coffee consumption is associated with a reduced risk of Type 2 diabetes .  Our aim was to investigate if coffee intake may also reduce the risk of latent autoimmune diabetes in adults , an autoimmune form of diabetes with features of Type 2 diabetes . METHODS We used data from a population -based case-control study with incident cases of adult onset ( ≥ 35 years ) diabetes , including 245 cases of latent autoimmune diabetes in adults ( glutamic acid decarboxylase antibody positive ) , 759 cases of Type 2 diabetes ( glutamic acid decarboxylase antibody negative ) , together with 990 control subjects without diabetes , r and omly selected from the population . Using question naire information on coffee consumption , we estimated the odds ratio of latent autoimmune diabetes in adults and Type 2 diabetes adjusted for age , sex , BMI , smoking , physical activity , alcohol , education and family history of diabetes . RESULTS Coffee intake was inversely associated with Type 2 diabetes ( odds ratio 0.92 , 95 % CI 0.87 - 0.98 per cup/day ) . With regard to latent autoimmune diabetes in adults , the general trend was weak ( odds ratio 1.04 , 95 % CI 0.96 - 1.13 ) , but stratification by degree of autoimmunity ( median glutamic acid decarboxylase antibody levels ) suggested that coffee intake may be associated with an increased risk of high glutamic acid decarboxylase antibody latent autoimmune diabetes in adults ( odds ratio 1.11 , 95 % CI 1.00 - 1.23 per cup/day ) . Furthermore , for every additional cup of coffee consumed per day , there was a 15.2 % ( P = 0.0268 ) increase in glutamic acid decarboxylase antibody levels . CONCLUSIONS Our findings confirm that coffee consumption is associated with a reduced risk of Type 2 diabetes . Interestingly , the findings suggest that coffee may be associated with development of autoimmunity and possibly an increased risk of more Type 1-like latent autoimmune diabetes in adults Purpose Coffee is known to contain phytochemicals with antioxidant potential . The aim of this study was to investigate possible antioxidant effects of coffee in healthy human volunteers . Methods A placebo-controlled intervention trial was carried out on 160 healthy human subjects , r and omised into three groups , receiving 3 or 5 cups of study coffee or water per day , for 8 weeks . Blood sample s were taken before , during , and after the intervention . Serum was used for analysis of blood lipids and st and ard clinical chemistry analytes . Peripheral blood mononuclear cells were isolated , and DNA damage ( str and breaks and oxidised bases ) was measured with the comet assay . The lipid oxidation product isoprostane 8-iso-PGF2α was assayed in urine sample s by LC – MS/MS . Results There was no significant effect of coffee consumption on the markers of oxidation of DNA and lipids . Creatinine ( in serum ) increased by a few per cent in all groups , and the liver enzyme γ-glutamyl transaminase was significantly elevated in serum in the 5 cups/day group . Other clinical markers ( including glucose and insulin ) , cholesterol , triacylglycerides , and inflammatory markers were unchanged . There was no effect of coffee  on blood pressure . Conclusion In a carefully controlled clinical trial with healthy subjects , up to 5 cups of coffee per day had no detectable effect , either beneficial or harmful , on human health BACKGROUND Increasing coffee intake was inversely associated with risk of type 2 diabetes in population s of European descent ; however , data from high-risk Asian population s are lacking as are data on tea intake in general . OBJECTIVE We investigated the prospect i ve associations between intakes of coffee , black tea , and green tea with the risk of type 2 diabetes in Singaporean Chinese men and women . DESIGN We analyzed data from 36 908 female and male participants in the Singapore Chinese Health Study aged 45 - 74 y in 1993 - 1998 who had multiple diet and lifestyle measures assessed and then were followed up between 1999 and 2004 . We used Cox regression models to investigate the association of baseline coffee and tea intakes with incident type 2 diabetes during follow-up , with adjustment for a number of possible confounding or mediating variables . RESULTS In multivariate models participants reporting > or = 4 cups of coffee/d had a 30 % reduction in risk of diabetes [ relative risk ( RR ) : 0.70 ; 95 % CI : 0.53 , 0.93 ] compared with participants who reported nondaily consumption . Participants reporting > or = 1 cup of black tea/d had a suggestive 14 % reduction in risk of diabetes ( RR : 0.86 ; 95 % CI : 0.74 , 1.00 ) compared with participants who reported 0 cups/d , and we observed no association with green tea . CONCLUSION Regular consumption of coffee and potentially black tea , but not green tea , is associated with lower risk of type 2 diabetes in Asian men and women in Singapore The aim of this study is to investigate the effect of green tea extract on patients with type 2 diabetes mellitus and lipid abnormalities on glycemic and lipid profiles , and hormone peptides by a double-blinded , r and omized and placebo-controlled clinical trial . This trial enrolled 92 subjects with type 2 diabetes mellitus and lipid abnormalities r and omized into 2 arms , each arm comprising 46 participants . Of the participants , 39 in therapeutic arm took 500 mg green tea extract , three times a day , while 38 in control arm took cellulose with the same dose and frequency to complete the 16-week study . Anthropometrics measurements , glycemic and lipid profiles , safety parameters , and obesity-related hormone peptides were analyzed at screening and after 16-week course . Within-group comparisons showed that green tea extract caused a significant decrease in triglyceride and homeostasis model assessment of insulin resistance index after 16 weeks . Green tea extract also increased significantly high density lipoprotein cholesterol . The HOMA-IR index decreased from 5.4±3.9 to 3.5±2.0 in therapeutic arm only . Adiponectin , apolipoprotein A1 , and apolipoprotein B100 increased significantly in both arms , but only glucagon-like peptide 1 increased in the therapeutic arm 
    Output:
    
The oolong tea group also showed a significant decrease in FBG , but the quality of evidence was very low .
In conclusion , green tea consumption might decrease FBG levels , especially in < 55-year-olds or Asian-based population