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Active, Not Recruiting

NCT Number: NCT04530916

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

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.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Hypertension Aging Arterial Occlusive Diseases Arteriosclerosis Atherosclerosis Cardiovascular Diseases Congenital, Hereditary, and Neonatal Diseases and Abnormalities Endocrine Gland Neoplasms Endocrine System Diseases Endothelial Dysfunction Genetic Diseases, Inborn Men Multiple Endocrine Neoplasia Multiple Endocrine Neoplasia Type 1 Neoplasms Neoplasms by Site Neoplasms, Multiple Primary Neoplastic Syndromes, Hereditary Vascular Diseases

Age range

45 year–70 year

Sex eligibility

Male

Study type

Interventional

Phase

Phase 1 / Phase 2

Primary location

Food and Nutrition Clinical Research Laboratory

Fort Collins, Colorado, 80523-1571, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Blueberry powder

Dietary Supplement

22 g/day wild blueberry powder

Placebo Powder

Dietary Supplement

22 g/day placebo powder

Primary outcomes

  1. Reactive hyperemia index

    Time frame: Baseline to 12 Weeks

    Endothelial function assessed as reactive hyperemia index using peripheral arterial tonometry (EndoPat)

Secondary outcomes

  1. Augmentation index

    Time frame: Baseline to 12 Weeks

    Arterial stiffness assessed as augmentation index using an automated blood pressure monitor (SphygmoCor)

  2. Pulse wave velocity

    Time frame: Baseline to 12 Weeks

    Arterial stiffness assessed as carotid-femoral pulse wave velocity using an automated blood pressure monitor (SphygmoCor)

  3. Endothelial cell protein expression

    Time frame: 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

  4. Hemoglobin A1c

    Time frame: Baseline to 12 Weeks

    Blood hemoglobin A1C will be measured

  5. Lipid profile

    Time frame: Baseline to 12 Weeks

    Blood lipid profiles will be measured

  6. Nitric oxide metabolites

    Time frame: Baseline to 12 Weeks

    Blood nitrate/nitrite will be measured

  7. ICAM-1

    Time frame: Baseline to 12 Weeks

    Blood ICAM-1 will be measured

  8. VCAM-1

    Time frame: Baseline to 12 Weeks

    Blood VCAM-1 will be measured

  9. Blood pressure

    Time frame: 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)

  10. Gut microbiota

    Time frame: Baseline to 12 Weeks

    Determine the effects on stool sample microbial populations

  11. Plasma blueberry polyphenol metabolites

    Time frame: Baseline to 12 Weeks

    Targeted analysis of plasma metabolites by GC-MS and LC-MS

Sponsors and collaborators

Lead sponsor

Colorado State University

Other

Collaborators

  • Wild Blueberry Association of North America

Registry information

Official study title

Antihypertensive and Vascular-Protective Effects of Wild Blueberries in Middle-Aged/Older Men and Postmenopausal Women.

Acronym: WB2020

Important dates

Study start
2020
Primary completion
2025
Study completion
2025
First posted
Aug 28, 2020
Registry last updated
Nov 17, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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