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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.

Status
Completed
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT01686282
Enrollment
48
Registered
2012-09-18
Start date
2012-01-31
Completion date
2014-01-31
Last updated
2015-01-14

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Blood Pressure

Keywords

Blood pressure, Arterial Stiffness, Blueberry Supplementation, Aortic Blood Pressure, Hypertension, Postmenopausal, Pulse Wave Velocity

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.

Interventions

8 weeks of freeze-dried taken in two doses of 22g each per day.

DIETARY_SUPPLEMENTPlacebo

8 weeks of freeze-dried taken in two doses of 22g each per day.

Sponsors

U.S. Highbush Blueberry Council
CollaboratorOTHER
Florida State University
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Investigator)

Eligibility

Sex/Gender
FEMALE
Age
45 Years to 65 Years
Healthy volunteers
No

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)

Design outcomes

Primary

MeasureTime frameDescription
Blood Pressure8 weeksBy measuring aortic blood pressure at rest and during physiological stress (handgrip exercise and post-exercise muscle ischemia).

Secondary

MeasureTime frameDescription
Autonomic Control of Heart Rate8 weeksBy measuring heart rate variability at rest and during physiological stress.
Endothelial Function8 weekBy measuring markers of vascular inflammation (adiponectin, leptin, endothelin-1, angiotensin II and 8-isoprostane).
Autonomic Control of Blood Pressure8 weeksBy measuring blood pressure variability and baroreflex sensitivity at rest and during physiological stress.
Oxidative Stress8 weeksBy measuring markers of oxidative stress (superoxide dismutase \[SOD\], nitrate/nitrite \[NOx\], ET-1, angiotensin II, 8-isoprostane, MDA, and oxidized LDL).
Arterial Stiffness8 WeekBy measuring the augmentation index and arterial stiffness at rest and during physiological stress (handgrip exercise and post-exercise muscle ischemia).
Inflammation8 weeksBy measuring a marker of inflammation (tumor necrosis factor-α \[TNF-α\]).

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026