Blood Pressure, Vascular Stiffness, Cardiovascular Risk Factor
Conditions
Keywords
Blood Pressure, Vascular Stiffness, Cardiovascular Risk Factor, Fruit and vegetable
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.
Interventions
OTHERLFV
1 apple/banana/small bunch of grapes per day plus 1 portion of carrot/pepper/tomato per day
OTHERHFV
4 portions of fruits (apples, bananas, grapes, pears) plus 4 portions of vegetables (carrots, cucumber, sweet peppers, tomatoes), of commonly consumed types per day excluding citrus fruits, cruciferous and allium vegetables.
OTHERCC
4 portions of citrus fruits (clementines, grapefruits, lemons, oranges) plus 4 portions of cruciferous vegetables (broccoli, brussels sprouts, cauliflower, kale, savoy cabbage) per day.
Sponsors
Imperial College London
University of Cambridge
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
40 Years to 65 Years
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Blood pressure | 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
| Measure | Time frame | Description |
|---|---|---|
| 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 | Measured by 16SrRNA gene sequencing |
| 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 | e.g. Stroop-test |
| 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 | Changes (end minus baseline values) in arterial stiffness (pulse wave analysis) |
| 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 | e.g. high-density lipoprotein |
| 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 | e.g. vitamin C |
| 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 | e.g. Interleukin-6 |
| 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 | (Un)targeted metabolic profiling by NMR and MS |
| 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 | (Un)targeted metabolic profiling by NMR and MS |
| 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 | e.g. Positive and Negative Affect Schedule (PANAS) that consists of two 10-item scales to measure both positive and negative affect. Each item is rated on a Likert scale of 1 (not at all) to 5 (very much). Positive and negative affect scores are added seperately to a reange from 10 to 50. Higher positive scores represents higher levels of positive affect. Lower negative scores respresaent lower levels of negative affect. |
| 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 | e.g. C-Reactive Protein |
Countries
United Kingdom
Outcome results
None listed