Quercetin reduces systolic blood pressure and plasma oxidised low-density lipoprotein concentrations in overweight subjects with a high-cardiovascular disease risk phenotype: a double-blinded, placebo-controlled cross-over study

• Published in: British journal of nutrition Vol. 102; no. 7; pp. 1065 - 1074
• Main Authors: Egert, Sarah, Bosy-Westphal, Anja, Seiberl, Jasmin, Kürbitz, Claudia, Settler, Uta, Plachta-Danielzik, Sandra, Wagner, Anika E., Frank, Jan, Schrezenmeir, Jürgen, Rimbach, Gerald, Wolffram, Siegfried, Müller, Manfred J.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 14.10.2009
• Subjects: Adult; adults; adverse effects; Aged; Anthropometry; Anthropometry - methods; Antioxidants; Antioxidants - adverse effects; Antioxidants - pharmacology; Biological and medical sciences; blood; Blood Glucose; Blood Glucose - metabolism; blood lipids; Blood Pressure; Blood Pressure - drug effects; Body Composition; Body Composition - drug effects; Body Weight; Body Weight - drug effects; Cardiovascular disease; Cardiovascular diseases; Cardiovascular Diseases - etiology; Cardiovascular Diseases - prevention & control; Cholesterol; complications; CVD; Diet; Dietary Supplements; drug effects; Epidemiologic Methods; etiology; Feeding. Feeding behavior; Female; Flavonoids; Fundamental and applied biological sciences. Psychology; Health risks; Heart Rate; Heart Rate - drug effects; Human and Clinical Nutrition; Humans; Inflammation; Inflammation Mediators; Inflammation Mediators - blood; Lipids; Lipids - blood; Lipoproteins, LDL; Lipoproteins, LDL - blood; Low density lipoprotein; Male; Metabolic disorders; metabolic syndrome; metabolism; methods; Middle Aged; Nutrition research; Nutritional status; Obesity; overweight; Overweight - blood; Overweight - complications; Overweight - physiopathology; Oxidative stress; Oxidised LDL; Patient Compliance; pharmacology; Phenotype; physiopathology; placebo-controlled cross-over study; placebos; prevention & control; Quercetin; Quercetin - adverse effects; Quercetin - pharmacology; risk factors; systolic blood pressure; Uric Acid; Uric Acid - blood; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Waist Circumference; Waist Circumference - drug effects; CVD; Blood pressure; Inflammation; Oxidised LDL; Quercetin; Human; Systolic pressure; High risk; Cardiovascular disease; Concentration; Blood plasma; Overweight; Lipoprotein LDL; Vertebrata; Phenotype; Mammalia; Double blind study; Hemodynamics
• ISSN: 0007-1145; 1475-2662; 1475-2662
• DOI: 10.1017/S0007114509359127

Regular consumption of flavonoids may reduce the risk for CVD. However, the effects of individual flavonoids, for example, quercetin, remain unclear. The present study was undertaken to examine the effects of quercetin supplementation on blood pressure, lipid metabolism, markers of oxidative stress, inflammation, and body composition in an at-risk population of ninety-three overweight or obese subjects aged 25–65 years with metabolic syndrome traits. Subjects were randomised to receive 150 mg quercetin/d in a double-blinded, placebo-controlled cross-over trial with 6-week treatment periods separated by a 5-week washout period. Mean fasting plasma quercetin concentrations increased from 71 to 269 nmol/l (P < 0·001) during quercetin treatment. In contrast to placebo, quercetin decreased systolic blood pressure (SBP) by 2·6 mmHg (P < 0·01) in the entire study group, by 2·9 mmHg (P < 0·01) in the subgroup of hypertensive subjects and by 3·7 mmHg (P < 0·001) in the subgroup of younger adults aged 25–50 years. Quercetin decreased serum HDL-cholesterol concentrations (P < 0·001), while total cholesterol, TAG and the LDL:HDL-cholesterol and TAG:HDL-cholesterol ratios were unaltered. Quercetin significantly decreased plasma concentrations of atherogenic oxidised LDL, but did not affect TNF-α and C-reactive protein when compared with placebo. Quercetin supplementation had no effects on nutritional status. Blood parameters of liver and kidney function, haematology and serum electrolytes did not reveal any adverse effects of quercetin. In conclusion, quercetin reduced SBP and plasma oxidised LDL concentrations in overweight subjects with a high-CVD risk phenotype. Our findings provide further evidence that quercetin may provide protection against CVD.