The Impact of Citrus Products on Cardiovascular Health

Overview

Epidemiological studies have indicated that the consumption of citrus fruit is inversely associated with the risk of cardiovascular disease. However, clinical data regarding the effects of blood orange juice upon endothelial function is scarce. This randomised, crossover study investigates whether blood orange juice compared to a control drink improves blood vessel function and other cardiovascular health indicators (such as blood pressure and blood lipids). All the subjects will be asked to consume blood orange juice and a control drink in a randomised order, each over a 2-week period, divided by a 1-week wash out period.

Full Title of Study: “Effects of Blood Orange Juice Consumption on Endothelial Function in Healthy Overweight/Obese Men and Premenopausal Women of European Origin”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Crossover Assignment
    • Primary Purpose: Prevention
    • Masking: Double (Investigator, Outcomes Assessor)
  • Study Primary Completion Date: June 21, 2017

Detailed Description

Endothelial function measured via flow mediated dilation (FMD), blood pressure, anthropometric measures, lipid profile, high-sensitivity C-reactive protein (hsCRP) and endothelin 1 (ET-1), cyclic guanosine monophosphate (cGMP) will be evaluated in healthy overweight/obese Caucasians prior to and following 2-week consumption of blood orange juice and a control drink. Evaluation of endothelial function as measured by FMD will be conducted on specific days of the menstrual cycle to minimise the fluctuation in oestrogen levels in premenopausal women, which will be monitored in serum samples.

Interventions

  • Dietary Supplement: Blood orange juice
  • Dietary Supplement: Control drink

Arms, Groups and Cohorts

  • Experimental: Blood orange juice
    • Subjects will be asked to consume blood orange juice (400 ml/day) for 2 weeks.
  • Placebo Comparator: Control drink
    • Subjects will be asked to consume a control drink (400 ml/day) for 2 weeks.

Clinical Trial Outcome Measures

Primary Measures

  • Changes in flow mediated dilation between baseline and endpoint within the intervention group vs. control group
    • Time Frame: Baseline and 2 weeks; after 1-week wash out, another baseline and 2 weeks.
    • FMD will be evaluated prior to and following 2-week consumption of either blood orange juice or a control drink.

Secondary Measures

  • Changes in blood pressure between baseline and endpoint within the intervention group vs. control group
    • Time Frame: Baseline and 2 weeks; after 1-week wash out, another baseline and 2 weeks.
    • Blood pressure will be measured prior to and following 2-week consumption of either blood orange juice or a control drink.
  • Changes in lipid profile between baseline and endpoint within the intervention group vs. control group
    • Time Frame: Baseline and 2 weeks; after 1-week wash out, another baseline and 2 weeks.
    • Serum total cholesterol, HDL cholesterol, LDL cholesterol will be measured prior to and following 2-week consumption of either blood orange juice or a control drink.
  • Changes in high sensitivity C-reactive protein between baseline and endpoint within the intervention group vs. control group
    • Time Frame: Baseline and 2 weeks; after 1-week wash out, another baseline and 2 weeks.
    • Serum hsCRP will be measured prior to and following 2-week consumption of either blood orange juice or a control drink.
  • Changes in endothelin-1 (ET-1) between baseline and endpoint within the intervention group vs. control group
    • Time Frame: Baseline and 2 weeks; after 1-week wash out, another baseline and 2 weeks.
    • Serum ET-1 will be measured prior to and following 2-week consumption of either blood orange juice or a control drink.
  • Changes in oestradiol between baseline and endpoint within the intervention group vs. control group
    • Time Frame: Baseline and 2 weeks; after 1-week wash out, another baseline and 2 weeks.
    • Serum oestradiol will be measured prior to and following 2-week consumption of either blood orange juice or a control drink.
  • Changes in flavanone metabolites between baseline and endpoint within the intervention group vs. control group
    • Time Frame: Baseline and 2 weeks; after 1-week wash out, another baseline and 2 weeks.
    • Flavanone metabolites will be measured prior to and following 2-week consumption of either blood orange juice or a control drink.
  • Changes in cyclic guanosine monophosphate (cGMP) between baseline and endpoint within the intervention group vs. control group
    • Time Frame: Baseline and 2 weeks; after 1-week wash out, another baseline and 2 weeks.
    • Cyclic guanosine monophosphate (cGMP) will be measured prior to and following 2-week consumption of either blood orange juice or a control drink.

Participating in This Clinical Trial

Inclusion Criteria

  • Generally healthy – Caucasians (of European origin) – BMI > 25 kg/m2 Exclusion Criteria:

  • Presence of cardiovascular diseases – Smoking – Use of medications or dietary supplements (vitamins, antioxidants) – On a special diet and/or a training program to change weight

Gender Eligibility: All

Minimum Age: 20 Years

Maximum Age: 60 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • University of Leeds
  • Provider of Information About this Clinical Study
    • Principal Investigator: Karen Birch, PhD – University of Leeds
  • Overall Official(s)
    • Lu Li, PhD, Principal Investigator, University of Leeds
    • Karen M Birch, PhD, Study Director, University of Leeds
    • Christine Bosch, PhD, Study Chair, University of Leeds

References

Muller-Delp JM, Lubahn DB, Nichol KE, Philips BJ, Price EM, Curran EM, Laughlin MH. Regulation of nitric oxide-dependent vasodilation in coronary arteries of estrogen receptor-alpha-deficient mice. Am J Physiol Heart Circ Physiol. 2003 Nov;285(5):H2150-7. doi: 10.1152/ajpheart.00966.2002. Epub 2003 Jul 24.

Perticone F, Ceravolo R, Candigliota M, Ventura G, Iacopino S, Sinopoli F, Mattioli PL. Obesity and body fat distribution induce endothelial dysfunction by oxidative stress: protective effect of vitamin C. Diabetes. 2001 Jan;50(1):159-65. doi: 10.2337/diabetes.50.1.159.

Thijssen DH, Black MA, Pyke KE, Padilla J, Atkinson G, Harris RA, Parker B, Widlansky ME, Tschakovsky ME, Green DJ. Assessment of flow-mediated dilation in humans: a methodological and physiological guideline. Am J Physiol Heart Circ Physiol. 2011 Jan;300(1):H2-12. doi: 10.1152/ajpheart.00471.2010. Epub 2010 Oct 15.

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