Study on the Effects of Epicatechin and Quercetin Supplementation on Vascular Function and Blood Pressure (FLAVO)

Study on the Effects of Epicatechin and Quercetin Supplementation on Vascular Function and Blood Pressure in Untreated (Pre)Hypertensive Subjects

Flavonoid-rich foods such as tea and cocoa have been identified as having a blood pressure-lowering effect. Part of this effect is thought to be due to the flavonoid content of these foods although it is currently unknown which flavonoids play a role. Epicatechin is one the major flavonoids in cocoa while quercetin is largely found in tea.

During this study the investigators plan to investigate the effects of pure epicatechin and quercetin supplementation on vascular function and blood pressure in untreated (prehypertensive) subjects by way of a three-armed double-blind crossover intervention. Participants will sequentially consume supplements containing quercetin, epicatechin or placebo for a period of 4 weeks. Before and after this 4 week period, measurements of vascular function and blood pressure will be taken.

The investigators hypothesize that the supplementation of epicatechin and quercetin will improve vascular function and blood pressure.

Study Overview

• Status: Completed
• Conditions: Hypertension; Endothelial Dysfunction
• Intervention / Treatment: Dietary supplement: Epicatechin; Dietary supplement: Quercetin; Dietary supplement: Placebo

Detailed Description

By means of a three-armed double-blind crossover intervention, the effects of pure flavonoid supplementation will be investigated. The products under investigation will be epicatechin and quercetin-3-glucoside. Subjects will be asked to consume either 160mg of quercetin-3-glucoside, 100mg of epicatechin or a placebo capsule for a period of 4 weeks. Measurements of vascular function and blood pressure will be taken before and after each 4-week intervention period. A 4-week washout period will be planned between each intervention.

Measurements of vascular function will include flow-mediated dilation, pulse wave analysis, pulse wave velocity and vasomotion as well as biomarkers of inflammation and vascular function.

• Study Type: Interventional
• Enrollment (Actual): 38
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Netherlands
  • Wageningen, Netherlands, 6703 HD
    • Wageningen University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 30 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Systolic Blood Pressure between 125 and 160 mmHg
• Age between 30 and 80 years
• BMI > 20 and ≤ 40
• No reported current or previous metabolic diseases
• No history of cardiovascular diseases
• No history of renal, liver or thyroid diseases
• No history of gastrointestinal diseases
• No diabetes mellitus
• Fasting laboratory parameters within normal range: complete blood count (RBC, WBC, PLT, HB, HT), renal function (serum creatinine, urea), liver function (ALAT, ASAT, ɣ-GT), and serum glucose.

Exclusion Criteria:

• Body mass index > 40 and ≤20
• Secondary hypertension
• Weight loss or weight gain of 5 kg or more during the last 2 months
• Usage of non-steroidal anti-inflammatory drugs (acetylsalicylic acid, ibuprofen, naproxen) and not able or willing to stop taking them from at least 4 weeks prior to the study
• Usage of cholesterol-lowering medication
• Daily usage of corticosteroids
• Medical treatment that may affect blood pressure and not able (or willing) to stop
• Taking nutritional supplements and unwilling to discontinue
• Lactating, pregnant or intention to become pregnant during study
• Reported dietary habits, medically prescribed diet, slimming diet
• Reported average alcohol consumption > 2 glasses/d (men) or >1 glass/d (women)
• Problems with consuming the supplements or following the study guidelines
• Unwilling to undergo home or office blood pressure measurements
• Recent blood donation i.e. 1 month (male subjects) or 2 months (female subjects) prior to the study and planned donation during the study period
• Reported intense sporting activities > 10 h/w
• Not agreeing to be informed about unexpected and medically relevant personal test-results, or not agreeing that their general practitioner will be informed about these results
• Participation in another biomedical trial less than 2 months before the start of the study or at the same time
• No signed informed consent form
• Clinical disorders that could interfere with the intervention
• Unable to comply with the study procedure (e.g. holidays, urine collection, blood sampling)
• Smokers
• Difficulty imaging brachial artery by ultrasonography

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Epicatechin; Subjects will be asked to consume supplements containing 100mg of epicatechin daily	Dietary supplement: Epicatechin; Subjects will be asked to consume supplements containing 100mg of epicatechin daily
Active Comparator: Quercetin; Subjects will be asked to consume supplements containing 160mg of quercetin-3-glucoside daily	Dietary supplement: Quercetin; Subjects will be asked to consume 160mg of quercetin-3-glucoside daily
Placebo Comparator: Placebo; Subjects will be asked to consume capsules containing a placebo (cellulose) daily	Dietary supplement: Placebo; Subjects will be asked to consume capsules containing placebo (cellulose) daily

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Endothelium-dependent flow-mediated dilation as a result of epicatechin and quercetin-3-glucoside supplementation	Change in arterial diameter as a result of 5 minute arterial occlusion (200mmHg). Arterial diameter will be measured by means of ultrasonography.	Baseline and every 4 weeks thereafter (weeks 4, 8, 12, 16 and 20)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in blood pressure as a result of epicatechin and quercetin-3-glucoside supplementation	Office BP (Dinamap, 4 consecutive measurements with 2-min intervals)and 24-hour ABPM (Spacelab; 1x24h)	Baseline and every 4 weeks thereafter (weeks 4, 8, 12, 16 and 20)
Change in pulse wave velocity as a result of epicatechin and quercetin supplementation	Measured using a SphygmoCor device at baseline and the end of each intervention	Baseline and every 4 weeks thereafter (weeks 4, 8, 12, 16 and 20)
Change in vasomotion as a result of epicatechin and quercetin supplementation	Measured using a PeriFlux 5001 device at baseline and the end of each intervention.	Baseline and every 4 weeks thereafter (weeks 4, 8, 12, 16 and 20)
Changes in biomarkers of endothelial function as a result of epicatechin and quercetin supplementation	Plasma analysis of endothelin-1, ADMA, MCP-1, sVCAM-1, sICAM-1, sE-selectin, sTM, CRP, SAA, IL-6, IL-8, TNF-α, vWF, nitric oxide	Baseline and every 4 weeks thereafter (weeks 4, 8, 12, 16 and 20)
Changes in peripheral blood mononuclear cell gene expression of markers of inflammation as a result of epicatechin and quercetin supplementation	PBMC gene expression of markers of inflammation	Baseline and every 4 weeks thereafter (weeks 4, 8, 12, 16 and 20)
Change in cardiovascular parameters in plasma as a result of epicatechin and quercetin supplementation	Total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides, insulin and glucose	Baseline and every 4 weeks thereafter (weeks 4, 8, 12, 16 and 20)
Changes in pulse wave analysis as a result of epicatechin and quercetin supplementation	Measured using a SphygmoCor device at baseline and the end of each intervention	Baseline and every 4 weeks thereafter (weeks 4, 8, 12, 16 and 20)
Adverse events	During the study subjects will be asked to maintain a diary in which they can report any adverse events they may have a result of the supplements. Diaries will be checked every 2 weeks. Study subjects will also be asked to contact the research team if they experience repeated adverse events.	Baseline and every 2 weeks thereafter (weeks 2, 4, 6, 8, 10, 12, 14, 16, 18 and 20)

Collaborators and Investigators

• Sponsor: Wageningen University
• Collaborators: Top Institute Food and Nutrition
• Investigators: Principal Investigator: Peter Hollman, PhD, Wageningen University

Publications and helpful links

General Publications

• Van den Eynde MDG, Geleijnse JM, Scheijen JLJM, Hanssen NMJ, Dower JI, Afman LA, Stehouwer CDA, Hollman PCH, Schalkwijk CG. Quercetin, but Not Epicatechin, Decreases Plasma Concentrations of Methylglyoxal in Adults in a Randomized, Double-Blind, Placebo-Controlled, Crossover Trial with Pure Flavonoids. J Nutr. 2018 Dec 1;148(12):1911-1916. doi: 10.1093/jn/nxy236.
• Dower JI, Geleijnse JM, Gijsbers L, Schalkwijk C, Kromhout D, Hollman PC. Supplementation of the Pure Flavonoids Epicatechin and Quercetin Affects Some Biomarkers of Endothelial Dysfunction and Inflammation in (Pre)Hypertensive Adults: A Randomized Double-Blind, Placebo-Controlled, Crossover Trial. J Nutr. 2015 Jul;145(7):1459-63. doi: 10.3945/jn.115.211888. Epub 2015 May 13.
• Dower JI, Geleijnse JM, Gijsbers L, Zock PL, Kromhout D, Hollman PC. Effects of the pure flavonoids epicatechin and quercetin on vascular function and cardiometabolic health: a randomized, double-blind, placebo-controlled, crossover trial. Am J Clin Nutr. 2015 May;101(5):914-21. doi: 10.3945/ajcn.114.098590. Epub 2015 Feb 25.

Helpful Links

• Website for the study (in dutch)
• Website of Division of Human Nutrition, Wageningen University, The Netherlands

Study record dates

Study Major Dates

• Study Start: September 1, 2012
• Primary Completion (Actual): March 1, 2013
• Study Completion (Actual): March 1, 2013

Study Registration Dates

• First Submitted: September 12, 2012
• First Submitted That Met QC Criteria: September 19, 2012
• First Posted (Estimate): September 24, 2012

Study Record Updates

• Last Update Posted (Estimate): April 23, 2013
• Last Update Submitted That Met QC Criteria: April 22, 2013
• Last Verified: November 1, 2012

More Information

Terms related to this study

• Keywords: Endothelial function; Blood pressure; Vascular function; Flavonoids; Epicatechin; Quercetin
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypertension; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Protective Agents; Antioxidants; Quercetin
• Other Study ID Numbers: NL4077208112