Resveratrol  significantly improves adiponectin but does not affect leptin concentrations .
Abstract The results of human clinical trials have revealed that the effects of resveratrol on adipokines are inconsistent .
Green Tea Extract and Catechol-O-Methyltransferase Genotype Modify Fasting Serum Insulin and Plasma Adiponectin Concentrations in a Randomized Controlled Trial of Overweight and Obese Postmenopausal Women.
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
Resveratrol  significantly improves adiponectin but does not affect leptin concentrations .
Abstract The results of human clinical trials have revealed that the effects of resveratrol on adipokines are inconsistent .