Impact of Oranges on Cardiovascular Health

Bioavailability of Flavanones Compounds and Their Impact on Cardiovascular Health

Cardiovascular disease (CVD) is the leading cause of deaths in the Western world. Established risk factors include high LDL cholesterol, high blood pressure and diabetes. Poor blood vessel health is considered a predictor of future CVD risk, but can be reversed. Several different measurements can be used to determine blood vessel health; such as blood pressure (BP), and newer techniques which measure blood flow through the arteries after a blood pressure cuff restricts blood flow for a few minutes in one arm.

Flavonoids are compounds found in plant-based foods, and are associated with a reduced risk of CVD. From the previous studies, there is strong evidence that orange juice and citrus foods which have higher amount of specific citrus flavonoids improved cardiovascular risk factors such as BP and blood vessel health. Absorption of citrus flavonoids occurs in the colon after bacteria breakdown the forms found in food. After the flavonoids are absorbed into the blood they are modification by liver enzymes before they are excreted in the urine. A large range of citrus flavonoid have been found excreted in the urinary, ranging anywhere from 0-57% of the dose. Variation in the potential health effect may reflect the level of the citrus flavonoid absorbed, and this is not often considered in human studies.

This study is a 4-week double-blinded, randomized, cross-over intervention trial using a commercially-available orange juice supplement and a placebo control. The aims of the study are to determine whether orange juice supplements reduce blood pressure and improve blood vessel health after 4 weeks. Furthermore, to determine if there is a relationship between absorption of flavonoids (as measured by urinary excretion) and changes in blood pressure or blood vessel health.

The participants will need to attend 4 sessions on 4 separate study days, every 4 weeks for 12 weeks. On each study day they will have their weight, height, waist circumference, and blood pressure measured. A finger-prick blood sample, using a single-use lancet (Accu-Chek Safe T Pro Plus), will be taken to check the fasting blood glucose level. Blood flow in fingertips will be monitored before and after reducing blood flow in your forearm using a blood pressure cuff (called an EndoPAT). Participants will be asked to collect urine for 24 hr on each of the study days, and to consume the supplements provided daily for two sets of 4 weeks (there will be 4 weeks in the middle without any supplements).

An improvement in blood pressure and/or blood flow will provide evidence that blood vessel health has improved through short-term (4 week) use of a citrus flavonoid supplement

Study Overview

• Status: Completed
• Conditions: Blood Pressure; Endothelial Dysfunction; Cardiovascular Disease Risk Reduction
• Intervention / Treatment: Dietary supplement: Placebo; Dietary supplement: Citrus supplement

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Phase 2; Phase 1

Contacts and Locations

Study Locations

• United Kingdom
  • West Yorkshire
    • Leeds, West Yorkshire, United Kingdom, LS2 9JT
      • School of Food Science and Nutrition, University of Leeds

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 30 years to 60 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• No known cardiovascular disease or diabetes
• Age between 30-60 years
• Heavier than average (Body mass index, BMI ≥ 25 kg/m2)
• Currently non smoker
• Willing to consume orange juice supplements for 2 months
• Male and female are equally eligible as not mentioned on advert

Exclusion Criteria:

• Those who Taken any antibiotics in the 2 months prior to the study
• Those who consume dietary or herbal supplements
• previous surgery on gastrointestinal tract
• Those who currently taking medication
• Current smokers, or ex-smokers ceasing < 3 months ago
• pregnant or breast feeding
• Those with known allergies to the intervention treatment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: placebo; Placebo administered to participant	Dietary supplement: Placebo
Active Comparator: Citrus supplement; Citrus supplement administered to participant	Dietary supplement: Citrus supplement

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
blood pressure	Change in systolic and diastolic blood pressure	Baseline and 4 weeks
An improvement in blood flow	Change in blood flow using Endo-PAT device	Baseline and 4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
blood glucose	Change in blood glucose level in plasma,	Baseline and 4 weeks
bioavailability of flavanones compounds	Change of urine flavanones from the baseline and after 4 weeks of each arm	Baseline and 4 weeks

Collaborators and Investigators

• Sponsor: University of Leeds
• Collaborators: Dr Andrea Day and Prof Gary Williamson
• Investigators: Principal Investigator: Abdurrahman M Sweidan, University of Leeds

Publications and helpful links

Helpful Links

• Click here for more information about this study: Impact of oranges on cardiovascular health

Study record dates

Study Major Dates

• Study Start: June 1, 2013
• Primary Completion (Actual): February 1, 2014
• Study Completion (Actual): March 1, 2014

Study Registration Dates

• First Submitted: August 20, 2013
• First Submitted That Met QC Criteria: September 4, 2013
• First Posted (Estimate): September 5, 2013

Study Record Updates

• Last Update Posted (Estimate): April 1, 2014
• Last Update Submitted That Met QC Criteria: March 31, 2014
• Last Verified: March 1, 2014

More Information

Terms related to this study

• Keywords: Bioavailability; Blood glucose; Flavanones; Blood vessel health
• Additional Relevant MeSH Terms: Cardiovascular Diseases
• Other Study ID Numbers: MEEC 12-025