Wild Blueberries and Cardiovascular Health in Middle-aged/Older Men and Postmenopausal Women

Phase 1

Recruiting

• Conditions: Hypertension; Men; Aging; Endothelial Dysfunction
• Interventions: Dietary Supplement: Blueberry Powder; Dietary Supplement: Placebo Powder

• Registration Number: NCT04530916
• Lead Sponsor: Colorado State University

Brief Summary

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality worldwide. Aging is the primary risk factor for CVD, in large part due to adverse modifications to the arteries. These modifications include vascular endothelial dysfunction and arterial stiffness. Vascular endothelial dysfunction is an initiating step in atherosclerosis, and is primarily caused by reduced nitric oxide (NO) bioavailability secondary to excessive superoxide-driven oxidative stress and inflammation. Endothelial dysfunction leads to arterial stiffness and the development of hypertension (HTN) which further increases CVD. Greater than 2/3 of the US population has elevated blood pressure or stage 1-HTN. As such, interventions that improve vascular endothelial dysfunction by increasing NO bioavailability and mitigating excessive oxidative stress and inflammation are needed. Blueberries are rich in bioactive compounds including flavonoids, phenolic acids, and pterostilbene. These compounds and their metabolites have been shown to attenuate oxidative stress and inflammation. The primary goal of this study is to assess the efficacy of blueberries to improve reduce blood pressure and improve vascular endothelial dysfunction and arterial stiffness in middle-aged/older men with elevated blood pressure or stage 1-HTN.

Detailed Description

Not available

Study Timeline

• Study Start: 2020-01-01
• Study First Submitted: 2020-01-27
• Study First Submitted QC: 2020-08-25
• Study First Posted: 2020-08-28
• Status Verified: 2024-08
• Last Update Submitted: 2024-08-05
• Last Update Posted: 2024-08-07
• Primary Completion: 2025-03-31
• Study Completion: 2025-12-31

Recruitment & Eligibility

• Status: RECRUITING
• Sex: Male
• Target Recruitment: 58

Inclusion Criteria

• Men and postmenopausal women
• Aged 45-70 years
• Elevated blood pressure or stage 1-Hypertension
• Ability to provide informed consent

Exclusion Criteria

• Have had a menstrual cycle within the past year
• Blood Pressure < 120 (systolic BP) or ≥ 140/90 mm Hg
• Reactive hyperemia index > 3.00%
• Taking > 1 antihypertensive medication, taking 1 antihypertensive medication more than 1 time per day, and/or taking the antihypertensive medication for < 3 months
• Diagnosed cancer, cardiovascular disease, diabetes, or gastrointestinal, kidney, liver, lung, and/or pancreatic disease
• Triglycerides > 350 mg/dL, low-density lipoprotein cholesterol (LDL-C) ≥ 190 mg/dL, hemoglobin A1c ≥ 6.5%, and/or taking a lipid-lowering or glucose-lowering medication
• Testosterone or estrogen replacement therapy use 6 months prior to study start
• Weight change ≥ 3 kg in the past 3 months, actively trying to lose weight, or unwilling to remain weight stable throughout the study
• Current smokers or history of smoking in the past 12 months
• Binge and/or heavy drinker (>3 drinks on any given occasion and/or >7 drinks/week for women, and >4 drinks on any given occasion and/or >14 drinks/week for men)
• Body mass index < 18.5 or > 40 kg/m2
• Antibiotic therapy within past two months
• Allergies or contraindication to study treatments or procedures

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Blueberry	Blueberry Powder	22 g blueberry powder per day
Control	Placebo Powder	22 g placebo control powder per day

Primary Outcome Measures

Name	Time	Method
Reactive hyperemia index	Baseline to 12 Weeks	Endothelial function assessed as reactive hyperemia index using peripheral arterial tonometry (EndoPat)

Secondary Outcome Measures

Name	Time	Method
Lipid profile	Baseline to 12 Weeks	Blood lipid profiles will be measured
VCAM-1	Baseline to 12 Weeks	Blood VCAM-1 will be measured
Endothelial cell protein expression	Baseline to 12 Weeks	Protein expression will be assessed as an exploratory analysis for markers of nitric oxide bioavailability, inflammation, and/or oxidative stress will be measured by quantitative immunofluorescence in biopsied venous endothelial cells
Augmentation index	Baseline to 12 Weeks	Arterial stiffness assessed as augmentation index using an automated blood pressure monitor (SphygmoCor)
Pulse wave velocity	Baseline to 12 Weeks	Arterial stiffness assessed as carotid-femoral pulse wave velocity using an automated blood pressure monitor (SphygmoCor)
Gut microbiota	Baseline to 12 Weeks	Determine the effects on stool sample microbial populations
Plasma blueberry polyphenol metabolites	Baseline to 12 Weeks	Targeted analysis of plasma metabolites by GC-MS and LC-MS
Nitric oxide metabolites	Baseline to 12 Weeks	Blood nitrate/nitrite will be measured
Blood pressure	Baseline to 12 Weeks	Brachial and Aortic blood pressure (systolic blood pressure, diastolic blood pressure, pulse pressure, aortic pressure) assessed using an automated blood pressure monitor (SphygmoCor)
Hemoglobin A1c	Baseline to 12 Weeks	Blood hemoglobin A1C will be measured
ICAM-1	Baseline to 12 Weeks	Blood ICAM-1 will be measured

Trial Locations

Locations (1)

Food and Nutrition Clinical Research Laboratory; 🇺🇸 Fort Collins, Colorado, United States