Clinical trial NCT01319786: Effect of a Polyphenol Rich Diet on Vascular and Platelet Function
Official title: Effect of a Polyphenol Rich Diet on Vascular and Platelet Function- a Randomised Control Trial
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Hypertension
Keywords: Hypertension
Microvascular function
Lead sponsor: Queen's University, Belfast
Sponsor class: OTHER
Collaborators: name: Belfast Health and Social Care Trust
First posted: 2011-03-22
Enrollment: 104
Sex: ALL
Minimum age (years): 40
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: 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.


Eligibility criteria: 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

Primary outcomes:
measure: Vascular function
timeFrame: Measured at weeks 4 and 12
Secondary outcomes:
measure: Platelet function, biomarkers of cardiovascular risk and heart rate variability
timeFrame: Measured at weeks 0, 4 and 12
Other outcomes:
Locations:
city: Belfast
country: United Kingdom
facility: Belfast Health and Social Care Trust
Study officials:
affiliation: Belfast Health and Social Care Trust
name: Pascal McKeown, MD
role: PRINCIPAL_INVESTIGATOR
affiliation: Queen's University, Belfast
name: Jayne Woodside, PhD
role: STUDY_DIRECTOR
affiliation: Queen's University, Belfast
name: Michelle McKinley, PhD
role: STUDY_DIRECTOR
References:
citation: 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.