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Native to South America and South East Asia, the dragon fruit (pitaya) has become increasingly popular world-wide due to their vivid hue and bizarre structure. More importantly, their high levels of bioactive phytochemical betalains has sparked considerable scientific interest. Recent findings from in vitro and in vivo animal studies tentatively suggest that betalains may have ameliorative effects on vascular function. This will be a first randomised controlled trial aimed to explore the impact of dragon fruit consumption on blood pressure and other vascular parameters in healthy individuals. The study will feature a randomised, double-blinded, placebo-controlled and crossover design with flow-mediated dilatation (FMD) as primary outcome along with blood pressure and arterial stiffness as secondary outcomes. Cardiovascular biomarkers as well as relevant metabolites will also be determined from blood and urine samples collected from participants.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Dragon fruit first then placebo | Experimental | 2 weeks of dragon fruit juice intake or placebo with crossover to the other |
|
| Placebo first then dragon fruit | Experimental | 2 weeks of dragon fruit juice intake or placebo with crossover to the other |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Dragon fruit juice drink | Dietary Supplement | Dragon fruit drink containing 24 g of freeze-dried dragon fruit powder dissolved in low nitrate water. |
|
| Measure | Description | Time Frame |
|---|---|---|
| Changes in flow mediated dilation (FMD) of the brachial artery | Determine changes in flow mediated dilation (FMD) of the brachial artery after 2 weeks consumption of 24 g freeze-dried dragon fruit. | Baseline & 2 weeks |
| Measure | Description | Time Frame |
|---|---|---|
| Changes in flow mediated dilation (FMD) of the brachial artery | Determine changes in flow mediated dilation (FMD) of the brachial artery at 2, 3, and 4 hour post consumption of 24 g freeze-dried dragon fruit. | Baseline & 2, 3 and 4 hour post-consumption |
| Changes in blood pressure |
| Measure | Description | Time Frame |
|---|---|---|
| Plasma and urine betalains and (poly)phenol metabolites | Measured by liquid chromotography- mass spectrometry (LC/MS) post consumption. | Baseline and 3 hours and 2 weeks post consumption |
Inclusion Criteria:
Healthy men and women aged 18-40 years old
Subjects are willing to maintain their normal eating/drinking habits and exercise habits to avoid changes in body.
weight over the duration of the study.
Are able to understand the nature of the study.
Able to give signed written informed consent.
Signed informed consent form.
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Ana Rodriguez-Mateos, PhD | King's College London | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| King's College London | London | England | SE1 9NH | United Kingdom |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 35265960 | Derived | Cheok A, Xu Y, Zhang Z, Caton PW, Rodriguez-Mateos A. Betalain-rich dragon fruit (pitaya) consumption improves vascular function in men and women: a double-blind, randomized controlled crossover trial. Am J Clin Nutr. 2022 May 1;115(5):1418-1431. doi: 10.1093/ajcn/nqab410. |
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| Placebo | Dietary Supplement | Drink with macro- and micro-nutrient matched against the intervention drink. |
|
Determine changes in systolic and diastolic blood pressure at 2, 3, and 4 hour post consumption of 24 g freeze-dried dragon fruit. |
| Baseline & 2, 3 and 4 hour post-consumption |
| Changes in blood pressure | Determine changes in systolic and diastolic blood pressure after 2 weeks post consumption of 24 g freeze-dried dragon fruit. | Baseline & 2 weeks |
| Changes in heart rate | Determine changes in heart rate post consumption of 24 g freeze-dried dragon fruit. | Baseline & 2, 3 and 4 hour and 2 weeks post-consumption |
| Changes blood flow velocity | Determine changes in blood flow velocity post consumption of 24 g freeze-dried dragon fruit. | Baseline & 2, 3 and 4 hour and 2 weeks post-consumption |
| Changes in pulse wave velocity (PWV) | Determine changes in pulse wave velocity post consumption of 24 g freeze-dried dragon fruit. | Baseline & 3 hour and 2 weeks post-consumption. |
| Changes augmentation Index (AIx) | Determine changes in augmentation index post consumption of 24 g freeze-dried dragon fruit. | Baseline & 3 hour and 2 weeks post-consumption. |
| Number of volunteers with treatment-related adverse events | The number of volunteers with treatment-related adverse events will be assessed by questionnaires and interviews. | Baseline & 12 weeks |