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

Blood Pressure Clinical Trial

Official title:

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.

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01686282
• Other study ID #: 021259
• Status: Completed
• Phase: Phase 2
• First received: September 11, 2012
• Last updated: January 12, 2015
• Start date: January 2012
• Est. completion date: January 2014

Study information

• Verified date: January 2015
• Source: Florida State University
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Food and Drug Administration
• Study type: Interventional

Clinical Trial Summary

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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 48
• Est. completion date: January 2014
• Est. primary completion date: March 2013
• Accepts healthy volunteers: No
• Gender: Female
• Age group: 45 Years to 65 Years

Eligibility

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 Design

Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Treatment

Related Conditions & MeSH terms

• Blood Pressure
• Hypertension

Intervention

Dietary Supplement:
• Freeze-dried Blueberry Powder
8 weeks of freeze-dried taken in two doses of 22g each per day.
• Placebo
8 weeks of freeze-dried taken in two doses of 22g each per day.

Locations

Country	Name	City	State
United States	The Department of Nutrition, Food, and Exercise Sciences, Florida State University	Tallahassee	Florida

Sponsors (2)

Lead Sponsor	Collaborator
Florida State University	U.S. Highbush Blueberry Council

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Blood Pressure	By measuring aortic blood pressure at rest and during physiological stress (handgrip exercise and post-exercise muscle ischemia).	8 weeks	No
Secondary	Autonomic Control of Blood Pressure	By measuring blood pressure variability and baroreflex sensitivity at rest and during physiological stress.	8 weeks	No
Secondary	Autonomic Control of Heart Rate	By measuring heart rate variability at rest and during physiological stress.	8 weeks	No
Secondary	Endothelial Function	By measuring markers of vascular inflammation (adiponectin, leptin, endothelin-1, angiotensin II and 8-isoprostane).	8 week	No
Secondary	Inflammation	By measuring a marker of inflammation (tumor necrosis factor-a [TNF-a]).	8 weeks	No
Secondary	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	No
Secondary	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	No