Impact of Oranges on Cardiovascular Health

Summary

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

Conditions

• Blood Pressure
• Endothelial Dysfunction
• Cardiovascular Disease Risk Reduction

Interventions

DIETARY_SUPPLEMENT

Citrus supplement

DIETARY_SUPPLEMENT

Placebo

Sponsors & Collaborators

• Dr Andrea Day and Prof Gary Williamson

  collaborator UNKNOWN

• University of Leeds

  lead OTHER

Principal Investigators

• Abdurrahman M Sweidan · University of Leeds

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

DOUBLE

Model

CROSSOVER

Eligibility

Min Age

30 Years

Max Age

60 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2013-06-30

Primary Completion

2014-02-28

Completion

2014-03-31

Countries

• United Kingdom

Study Locations