Blueberry Consumption Improves Vascular Function and Lowers Blood Pressure in Postmenopausal Women With Pre- and Stage 1-hypertension

Daily Incorporation of Blueberries Into a Diet Favorably Improves Vascular Function and Lowers Aortic Blood Pressure in Postmenopausal Women With Pre- and Stage 1-hypertension.

Cardiovascular disease (CVD) continues to be the leading cause of death in the U.S. Americans have been more concerned about their blood cholesterol levels and dietary cholesterol intakes rather than their overall cardiovascular health risk factors leading to CVD such as hypertension, vascular dysfunction, inadequate consumption of fruits and vegetables and physical activity. Statistics show that approximately 91% of individuals with CVD have vascular dysfunction which is attributed to endothelial and autonomic dysfunction leading to increased arterial stiffness.

The investigators long-term goal is to provide feasible and effective dietary ways for pre- and stage 1- hypertensive individuals to normalize their blood pressure (BP), improve vascular function and thereby reducing their cardiovascular risk and enhancing the quality of life. Blueberries are a rich source of phenolic compounds and these compounds may play an important role in promoting cardiovascular health. Considering the strong possibility that phytochemicals present in blueberry work additively or synergistically, it would be ideal to investigate the cardioprotective effects of blueberry as a whole. The investigators overall objective to bring forth evidence that blueberry consumption will reduce BP and cardiovascular risk factors including endothelial dysfunction, arterial stiffness, and autonomic dysfunction in pre- and stage 1-hypertensive postmenopausal women. The investigators hypothesize that blueberry supplementation will improve vascular function and will lower blood pressure in postmenopausal women with pre-hypertension. The findings of this study will provide a foundation for disseminating feasible, safe approaches for preventing and combating hypertension at its early stage which does not require drug therapy.

Study Overview

• Status: Completed
• Conditions: Blood Pressure
• Intervention / Treatment: Dietary supplement: Placebo; Dietary supplement: Freeze-dried Blueberry Powder

Detailed Description

The purpose of this study is to examine the effects of 22 grams of freeze-dried blueberry intake on a daily basis for eight weeks in:

The purpose of the study is to examine the effects of 22 grams of freeze-dried blueberry intake on a daily basis for eight weeks on arterial function and blood pressure in postmenopausal women with pre- and stage 1-hypertension. The specific aims of the study are:

1. To investigate the extent to which daily consumption of 22 g blueberry drink-mix reduces blood pressure in individuals with pre- and stage 1-hypertension.
2. To determine whether daily consumption of 22 g blueberry drink-mix will improve the autonomic control of blood pressure and heart rate in individuals with pre- and stage 1-hypertension.
3. To measure serum markers of oxidative stress to determine whether increased antioxidant defense is in part responsible for blueberry's vascular protective effects.

• Study Type: Interventional
• Enrollment (Actual): 48
• Phase: Phase 2

Contacts and Locations

Study Locations

• United States
  • Florida
    • Tallahassee, Florida, United States, 32306
      • The Department of Nutrition, Food, and Exercise Sciences, Florida State University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 45 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

Description

Inclusion Criteria:

• 40 women (1 to 10 years after natural menopause or bilateral oophorectomy) 45-65 years of age.
• Seated blood pressure ≥ 130/85 mm Hg but ≤ 160/90 mm Hg.

Exclusion Criteria:

• Blood pressure >160/100 mmHg
• Taking insulin
• Cardiovascular disease
• Active cancer
• Asthma
• Glaucoma
• Thyroid disease
• Kidney disease
• Liver disease
• Pancreatic disease
• Enrollment in a weight loss program
• Heavy smokers (>20 cigarettes per day)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo; 8 weeks of freeze-dried blueberry powder taken in two doses of 22g each per day.	Dietary supplement: Placebo; 8 weeks of freeze-dried taken in two doses of 22g each per day.
Experimental: Blueberry; 8 weeks of freeze-dried blueberry powder taken in two doses of 22g each per day.	Dietary supplement: Freeze-dried Blueberry Powder; 8 weeks of freeze-dried taken in two doses of 22g each per day.; Other Names: U.S. Highbush Blueberry Council

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood Pressure	By measuring aortic blood pressure at rest and during physiological stress (handgrip exercise and post-exercise muscle ischemia).	8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Autonomic Control of Blood Pressure	By measuring blood pressure variability and baroreflex sensitivity at rest and during physiological stress.	8 weeks
Autonomic Control of Heart Rate	By measuring heart rate variability at rest and during physiological stress.	8 weeks
Endothelial Function	By measuring markers of vascular inflammation (adiponectin, leptin, endothelin-1, angiotensin II and 8-isoprostane).	8 week
Inflammation	By measuring a marker of inflammation (tumor necrosis factor-α [TNF-α]).	8 weeks
Oxidative Stress	By measuring markers of oxidative stress (superoxide dismutase [SOD], nitrate/nitrite [NOx], ET-1, angiotensin II, 8-isoprostane, MDA, and oxidized LDL).	8 weeks
Arterial Stiffness	By measuring the augmentation index and arterial stiffness at rest and during physiological stress (handgrip exercise and post-exercise muscle ischemia).	8 Week

Collaborators and Investigators

• Sponsor: Florida State University
• Collaborators: U.S. Highbush Blueberry Council
• Investigators: Principal Investigator: Arturo Figueroa, MD, PhD, Florida State University; Principal Investigator: Sarah A Johnson, PhD, RD, CSO, Florida State University

Publications and helpful links

General Publications

• Johnson SA, Figueroa A, Navaei N, Wong A, Kalfon R, Ormsbee LT, Feresin RG, Elam ML, Hooshmand S, Payton ME, Arjmandi BH. Daily blueberry consumption improves blood pressure and arterial stiffness in postmenopausal women with pre- and stage 1-hypertension: a randomized, double-blind, placebo-controlled clinical trial. J Acad Nutr Diet. 2015 Mar;115(3):369-377. doi: 10.1016/j.jand.2014.11.001. Epub 2015 Jan 8.

Study record dates

Study Major Dates

• Study Start: January 1, 2012
• Primary Completion (Actual): March 1, 2013
• Study Completion (Actual): January 1, 2014

Study Registration Dates

• First Submitted: September 11, 2012
• First Submitted That Met QC Criteria: September 12, 2012
• First Posted (Estimate): September 18, 2012

Study Record Updates

• Last Update Posted (Estimate): January 14, 2015
• Last Update Submitted That Met QC Criteria: January 12, 2015
• Last Verified: January 1, 2015

More Information

Terms related to this study

• Keywords: Hypertension; Arterial Stiffness; Pulse Wave Velocity; Blood pressure; Postmenopausal; Blueberry Supplementation; Aortic Blood Pressure
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypertension
• Other Study ID Numbers: 021259