Effect of a Polyphenol Rich Diet on Vascular and Platelet Function (PPhIT)

Effect of a Polyphenol Rich Diet on Vascular and Platelet Function- a Randomised Control Trial

Previous work has shown that increasing fruit and vegetable intake in patients with high blood pressure improves cardiovascular function. Research indicates that this may be partly owing to compounds called polyphenols, which are found in abundance in fruits and vegetables and other foods such as wine, tea and dark chocolate. The investigators now wish to test if consuming fruits and vegetables (including berries which are very rich in polyphenols), as well as dark chocolate, has further benefits for cardiovascular function. A total of 110 subjects with high blood pressure will be recruited and asked to follow a low polyphenol diet (2 portions of fruit and vegetables daily and no berries or dark chocolate) for four weeks (a washout period). They will then be randomised to continue this diet or to consume 6 portions of fruits and vegetables (to include 1 portion berries) and 1 portion of dark chocolate daily for 8 weeks. The fruit, vegetables and dark chocolate will be provided free of charge and delivered to the homes of the participants who are randomised to the high fruit and vegetable arm of the study.

Assessment of microvascular and platelet function will be undertaken before and after consuming this diet. Improvements in these tests of cardiovascular function have previously been linked to reduced risks of heart disease in people with high blood pressure. This study will provide evidence as to whether or not a polyphenol rich diet can reduce the risk of developing heart disease.

Study Overview

• Status: Completed
• Conditions: Hypertension
• Intervention / Treatment: Other: Two portions of fruit and vegetables per day (excluding berries and dark chocolate); Other: Six portions of fruit and vegetables per day (one of which must be berries) and 50g dark chocolate.

• Study Type: Interventional
• Enrollment (Actual): 104
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Belfast, United Kingdom, BT12 6BJ
    • Belfast Health and Social Care Trust

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age 40-65 years old
• Systolic blood pressure 140-179 mmHg or diastolic blood pressure 90-109 mmHg

Exclusion Criteria:

• diabetes mellitus
• an acute coronary syndrome or transient ischaemic attack within the past 3 months
• special dietary requirements, food sensitivities or vegetarian/vegan diet by choice
• oral anticoagulation therapy
• body mass index greater than 35kg/m2
• excessive alcohol consumption (defined as > 28 units/week in men and 21 units/week in women)
• fasting triglyceride concentration > 4 mmol/l
• pregnancy/lactation
• taking antioxidant supplements
• medical conditions or dietary restrictions that would substantially limit ability to complete the study requirements

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Low- polyphenol diet	Other: Two portions of fruit and vegetables per day (excluding berries and dark chocolate); Two portions of fruit and vegetables per day (excluding berries and dark chocolate)
Active Comparator: High-polyphenol diet	Other: Six portions of fruit and vegetables per day (one of which must be berries) and 50g dark chocolate.; Six portions of fruit and vegetables per day (one of which must be berries) and 50g dark chocolate.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Vascular function	Pharmacological provocation of endothelium-dependent vasomotion.	Measured at weeks 4 and 12

Secondary Outcome Measures

Outcome Measure	Time Frame
Platelet function, biomarkers of cardiovascular risk and heart rate variability	Measured at weeks 0, 4 and 12

Collaborators and Investigators

• Sponsor: Queen's University, Belfast
• Collaborators: Belfast Health and Social Care Trust
• Investigators: Principal Investigator: Pascal McKeown, MD, Belfast Health and Social Care Trust; Study Director: Jayne Woodside, PhD, Queen's University, Belfast; Study Director: Michelle McKinley, PhD, Queen's University, Belfast

Publications and helpful links

General Publications

• Noad RL, Rooney C, McCall D, Young IS, McCance D, McKinley MC, Woodside JV, McKeown PP. Beneficial effect of a polyphenol-rich diet on cardiovascular risk: a randomised control trial. Heart. 2016 Sep 1;102(17):1371-9. doi: 10.1136/heartjnl-2015-309218. Epub 2016 May 10.

Study record dates

Study Major Dates

• Study Start: January 1, 2011
• Primary Completion (Actual): August 1, 2013
• Study Completion (Actual): August 1, 2015

Study Registration Dates

• First Submitted: March 21, 2011
• First Submitted That Met QC Criteria: March 21, 2011
• First Posted (Estimate): March 22, 2011

Study Record Updates

• Last Update Posted (Estimate): October 28, 2015
• Last Update Submitted That Met QC Criteria: October 26, 2015
• Last Verified: October 1, 2015

More Information

Terms related to this study

• Keywords: Hypertension; Microvascular function
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypertension
• Other Study ID Numbers: QueensUBelfast