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

Phase 2

Completed

• Conditions: Blood Pressure

• Registration Number: NCT01686282
• Lead Sponsor: Florida State University

Brief 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.

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 Timeline

• Study Start: 2012-01
• Study First Submitted: 2012-09-11
• Study First Submitted QC: 2012-09-12
• Study First Posted: 2012-09-18
• Primary Completion: 2013-03
• Study Completion: 2014-01
• Status Verified: 2015-01
• Last Update Submitted: 2015-01-12
• Last Update Posted: 2015-01-14

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Female
• Target Recruitment: 48

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

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

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

Secondary Outcome Measures

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

Trial Locations

Locations (1)

The Department of Nutrition, Food, and Exercise Sciences, Florida State University; 🇺🇸 Tallahassee, Florida, United States