Green tea extract reduces blood pressure, inflammatory biomarkers, and oxidative stress and improves parameters associated with insulin resistance in obese, hypertensive patients

• Published in: Nutrition research (New York, N.Y.) N.Y.), 2012-06, Vol.32 (6), p.421-427
• Main Authors: Bogdanski, Pawel, Suliburska, Joanna, Szulinska, Monika, Stepien, Marta, Pupek-Musialik, Danuta, Jablecka, Anna
• Format: Article
• Language: English
• Subjects: Adult; antioxidants; Biological and medical sciences; biomarkers; Biomarkers - blood; blood glucose; blood lipids; Blood Pressure - drug effects; C-Reactive Protein; cholesterol; Double-Blind Method; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Gastroenterology and Hepatology; glucose; Green tea; high density lipoprotein; Humans; Hypertension; Hypertension - complications; Hypertension - drug therapy; Hypertension - physiopathology; Inflammation; Inflammation - complications; Inflammation - drug therapy; Inflammation - physiopathology; insulin; Insulin Resistance; Lipoproteins, HDL - blood; Lipoproteins, LDL - blood; low density lipoprotein; Male; Middle Aged; Obesity; Obesity - complications; Obesity - drug therapy; Obesity - physiopathology; Oxidative stress; Oxidative Stress - drug effects; patients; placebos; Plant Extracts - pharmacology; Polyphenol epigallocatechin-3-gallate; Randomized trial; risk factors; systolic blood pressure; Tea - chemistry; triacylglycerols; Triglycerides - blood; tumor necrosis factors; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0271-5317; 1879-0739
• DOI: 10.1016/j.nutres.2012.05.007

Green tea (GT) consumption is known to be associated with enhanced cardiovascular and metabolic health. The purpose of this study is to examine the hypothesis that supplementation with GT alters insulin resistance and associated cardiovascular risk factors in obese, hypertensive patients. In a double-blind, placebo-controlled trial, 56 obese, hypertensive subjects were randomized to receive a daily supplement of 1 capsule that contained either 379 mg of GT extract (GTE) or a matching placebo, for 3 months. At baseline and after 3 months of treatment, the anthropometric parameters, blood pressure, plasma lipid levels, glucose levels, creatinine levels, tumor necrosis factor α levels, C-reactive protein levels, total antioxidant status, and insulin levels were assessed. Insulin resistance was evaluated according to the homeostasis model assessment–insulin resistance protocol. After 3 months of supplementation, both systolic and diastolic blood pressures had significantly decreased in the GTE group as compared with the placebo group (P < .01). Considerable (P < .01) reductions in fasting serum glucose and insulin levels and insulin resistance were observed in the GTE group when compared with the placebo group. Serum tumor necrosis factor α and C-reactive protein were significantly lower, whereas total antioxidant status increased in the GTE group compared with the placebo (P < .05). Supplementation also contributed to significant (P < .05) decreases in the total and low-density lipoprotein cholesterol and triglycerides, but an increase in high-density lipoprotein cholesterol. In conclusion, daily supplementation with 379 mg of GTE favorably influences blood pressure, insulin resistance, inflammation and oxidative stress, and lipid profile in patients with obesity-related hypertension.