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

Study Overview
=================
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: 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. 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. To measure serum markers of oxidative stress to determine whether increased antioxidant defense is in part responsible for blueberry's vascular protective effects.

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.

Conditions
-----------------
Blood Pressure

Intervention / Treatment
-----------------
* Dietary Supplement: Freeze-dried Blueberry Powder
* Dietary Supplement: Placebo


Participation Criteria
=================
Eligibility Criteria
-----------------
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)

Ages Eligible for Study
-----------------
Minimum Age: 45 Years
Maximum Age: 65 Years

Sexes Eligible for Study
-----------------
Female

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>8 weeks of freeze-dried blueberry powder taken in two doses of 22g each per day. | Dietary Supplement: Placebo<br>* 8 weeks of freeze-dried taken in two doses of 22g each per day.<br>|
| Experimental: Blueberry<br>8 weeks of freeze-dried blueberry powder taken in two doses of 22g each per day. | Dietary Supplement: Freeze-dried Blueberry Powder<br>* 8 weeks of freeze-dried taken in two doses of 22g each per day.<br>* 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 | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Blood pressure, Arterial Stiffness, Blueberry Supplementation, Aortic Blood Pressure, Hypertension, Postmenopausal, Pulse Wave Velocity