The Effects of Types of Fruits and Vegetables on Vascular Function in Prehypertensive Participants: a Pilot Study
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- University of Cambridge
- Enrollment
- 36
- Locations
- 2
- Primary Endpoint
- Blood pressure
Study Overview
Brief Summary
The CIRCUS study is a randomised controlled, cross-over trial to evaluate the effects of increased intakes of citrus fruits and cruciferous vegetables on vascular function in 36 untreated, prehypertensive participants.
Detailed Description
The study comprises three 14-day dietary intervention periods, preceded by one week run-in period and separated by one week wash-out periods, 9 weeks in total. The diet will be fully controlled and provided by the researchers. Participants will receive in random order three interventions:
- 1 portion of fruits plus 1 portion of vegetables, of commonly consumed types per day. Intakes are at 25th percentile of UK consumption and will exclude citrus fruits, cruciferous and allium vegetables.
- 4 portions of fruits plus 4 portions of vegetables, of commonly consumed types per day excluding citrus fruits, cruciferous and allium vegetables.
- 4 portions of citrus fruits plus 4 portions of cruciferous vegetables per day.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Prevention
- Masking
- None
Eligibility Criteria
- Ages
- 40 Years to 65 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •40 - 65 years
- •Average systolic blood pressure of 125-140 mmHg at 2 measurements separated by >30 minutes
- •No use of antihypertensive medication
- •No reported current or previous diabetes mellitus, (secondary) hypertension, or metabolic, cardiovascular, renal, liver, thyroid, gastrointestinal diseases
- •Body Mass Index between 20 - 35 kg/m2
- •Non-smoker
- •Average fruit and vegetable consumption of <4 portions per day (UK average, 40-65 years), or willing to reduce habitual daily fruit and vegetable intake.
Exclusion Criteria
- •Any medication likely to interfere with energy metabolism, appetite regulation and hormonal balance.
- •Excessive alcohol intake of > 21 units per week (females) or >28 units per week (male) and not willing to limit alcohol intake to maximum of 1 unit/day
- •Physical activity of >=10 hours/week of moderate to vigorous physical activity
- •Weight loss or gain of >=3 kg in the preceding 3 months
- •Use of dietary supplements or unwilling to stop supplement use >= 2 weeks before enrolment and during intervention
- •Pregnancy or lactation
- •Intervention specific factors, including:
- •Unable or unwilling to consume provided diets during the intervention
- •Unsufficient storage space for provided diets
- •Food sensitivities or vegetarian/vegan diet by choice
- •Participation in another intervention study at the same time
- •Living > 15 miles from the Imperial/NIHR Clinical Research Facility at Hammersmith Hospital
- •No signed informed consent
Arms & Interventions
Low Fruits and Vegetables (LFV)
1 portion of fruits plus 1 portion of vegetables, of commonly consumed types per day.
Intakes are at 25th percentile of UK consumption (NDNS) and will exclude citrus fruits, cruciferous and allium vegetables.
Intervention: LFV (Other)
High Fruits and Vegetables (HFV)
4 portions of fruits plus 4 portions of vegetables, of commonly consumed types per day excluding citrus fruits, cruciferous and allium vegetables.
Intervention: HFV (Other)
High Citrus fruits and Cruciferous vegetables (CC)
4 portions of citrus fruits plus 4 portions of cruciferous vegetables per day excluding any other types of fruits and vegetables including allium vegetables.
Intervention: CC (Other)
Outcomes
Primary Outcomes
Blood pressure
Time Frame: Measured on the morning after each of three recurring run-in periods and after each of three recurring 2-week intervention periods, 6 times total during 9 weeks
Changes in systolic and diastolic blood pressure (mmHg) measured by automated oscillometric device (average of 3 measurements).
Secondary Outcomes
- Markers of low-grade inflammation measured in fasted blood samples(Measured on the morning after each of three recurring run-in periods and after each of three recurring 2-week intervention periods, 6 times total during 9 weeks)
- Urinary metabolic profiles(Measured on the morning after each of three recurring run-in periods and after each of three recurring 2-week intervention periods, 6 times total during 9 weeks)
- Arterial stiffness(Measured on the morning after each of three recurring run-in periods and after each of three recurring 2-week intervention periods, 6 times total during 9 weeks)
- Established objective markers of food intake(Measured on the morning after each of three recurring run-in periods and after each of three recurring 2-week intervention periods, 6 times total during 9 weeks)
- Faecal microbiome composition(Measured on the morning after each of three recurring run-in periods and after each of three recurring 2-week intervention periods, 6 times total during 9 weeks)
- Circulatory metabolic profiles(Measured on the morning after each of three recurring run-in periods and after each of three recurring 2-week intervention periods, 6 times total during 9 weeks)
- Markers of cardiometabolic health measured in fasted blood samples(Measured on the morning after each of three recurring run-in periods and after each of three recurring 2-week intervention periods, 6 times total during 9 weeks)
- Markers of endothelial function measured in fasted blood samples(Measured on the morning after each of three recurring run-in periods and after each of three recurring 2-week intervention periods, 6 times total during 9 weeks)
- Self-rated general health and mental well-being(Measured on the morning after each of three recurring run-in periods and after each of three recurring 2-week intervention periods, 6 times total during 9 weeks)
- Cognitive function(Measured on the morning after each of three recurring run-in periods and after each of three recurring 2-week intervention periods, 6 times total during 9 weeks)
Investigators
Linda Oude Griep
Senior Research Associate
University of Cambridge