Wild Blueberries for Gut, Brain, and Heart Health in Adults with High Blood Pressure

Not Applicable

Recruiting

• Conditions: Overweight; Hypertension (without Type 2 Diabetes Mellitus); High Blood Pressure; Male; Female; Adult; Cognition; Endothelial Function (reactive Hyperemia); Oxidative Stress; Diet

• Registration Number: NCT06735599
• Lead Sponsor: Georgia State University

Brief Summary

The purpose of the study is to determine the effectiveness of wild blueberries on cardiovascular health, cognitive function, and gut microbiota composition in non-Hispanic Black and White adults with elevated blood pressure.

Detailed Description

Hypertension (HTN), or high blood pressure (BP) is a major modifiable risk factor for heart disease, the leading cause of death worldwide. In the U.S., 121.5 million adults have high BP and only 25% have their BP under control. The 2022 Heart Disease and Stroke Statistics indicated that the incidence of high BP was higher among non-Hispanic Black (NHB) compared to non-Hispanic White (NHW) adults. Berries are rich in fiber and phytochemicals and have several health benefits. A 14-year follow-up of the Nurses' Health Study I and II and the Health Professional Follow-Up Study revealed a significant reduction in the risk of HTN (8%) among individuals in the highest quintile of anthocyanin intake compared to the lowest quintile. Blueberries are rich in fiber and phytochemicals that may be responsible for their health benefits. Studies have shown that daily blueberry consumption improves heart, cognitive, and intestinal health in different populations. Yet, a comprehensive study exploring and comparing the effectiveness of wild blueberries for cardiovascular, intestinal, and cognitive function parameters and their association in NHB and NHW adults with high BP has not been conducted to date.

Thus, the overall objective of this timely study is to determine and compare the effectiveness of a freeze-dried wild blueberry intervention on cardiovascular and gut health in NHB and NHW adults with high BP and assess whether these health benefits are associated with improvements in memory and other important thinking abilities for productivity and quality of life.

Therefore, this 8-week randomized, placebo-controlled parallel-arm clinical trial aims to assess whether daily consumption of 22 g of freeze-dried wild blueberry powder improves gut, cardiovascular, and cognitive function in NHB and NHW adults with elevated blood pressure and stage 1 hypertension. Investigators hypothesize that daily consumption of wild blueberries will improve cardiovascular parameters, gut dysbiosis, and cognitive function. To test these hypotheses, the following specific aims are proposed. To investigate whether daily consumption of 22 g of freeze-dried wild blueberry powder:

* Reduces BP, improves endothelial function, arterial stiffness, and microcirculation.

* Favorably modulates gut microbiota composition.

* Improves cognitive function (verbal memory and executive functions \[inhibition, working memory, cognitive flexibility\]).

* Improves serum markers of oxidative stress and inflammation.

Additionally, investigators will also explore whether changes in the gut microbiota are associated with changes in cardiometabolic and cognitive function outcomes and whether changes in cardiometabolic outcomes are associated with changes in cognitive function parameters globally and within each race.

Study Timeline

• Study Start: 2024-09-17
• Study First Submitted: 2024-11-05
• Study First Submitted QC: 2024-12-11
• Study First Posted: 2024-12-16
• Status Verified: 2025-03
• Last Update Submitted: 2025-03-18
• Last Update Posted: 2025-03-19
• Primary Completion: 2025-12-01
• Study Completion: 2026-01-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 80

Inclusion Criteria

• Individuals 45-65 years of age
• Diagnosis of elevated blood pressure or stage 1 hypertension (systolic blood pressure = 120-139 mmHg and/or diastolic blood pressure = 80-89 mmHg) for at least 6 months
• BMI 25-30 kg/m2 via anthropometric measurements.
• Ability to give consent

Exclusion Criteria

• Allergies to berries
• Use of one hypertensive drug for less than three months
• Use of more than one anti-hypertensive drug, insulin, antibiotics, and anti-inflammatory drugs, active cancer, gastrointestinal, renal, cardiovascular, thyroid, and neurological disorders or severe head injury
• Smoking
• Alcohol consumption (>2 drinks/day)
• Consuming antioxidant, probiotic, and prebiotic supplements
• Pregnant or lactating
• Participating in a weight loss program

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Ambulatory Blood Pressure	Baseline, 4 weeks, and 8 weeks	Assessment of whole-day ambulatory blood pressure during daytime and nighttime periods.
Pulse Wave Velocity	Baseline, 4 weeks, and 8 weeks	Arterial Stiffness will be measured by pulse wave velocity using SphygmCor

Secondary Outcome Measures

Name	Time	Method
Reactive Hyperemia Index	Baseline, 4 weeks, and 8 weeks	Assessment of endothelial function in response to increased shear stress using EndoPAT2000
Gut Microbiota Composition	Baseline, 4 weeks, and 8 weeks	Analysis of stool sample for determination of absolute levels of bacteria and relative species composition
Global Cognitive Ability	Screening	Measured using NIH Toolbox Picture Vocabulary and Oral Reading Recognition test
Performance Validity	Baseline, 4 weeks, and 8 weeks	Assessed using Rey 15
Working Memory	Baseline, 4 weeks, and 8 weeks	Measured using Digit Span and NIH Toolbox List Sorting
Processing Speed	Baseline, 4 weeks, and 8 weeks	Measured using NIH Toolbox Pattern Comparison and Oral Symbol Digit tests
Verbal Memory & Recognition	Baseline, 4 weeks, and 8 weeks	Measured using Rey Auditory Verbal Learning Test with appropriate alternate forms
Cognitive Inhibition	Baseline, 4 weeks, and 8 weeks	Assessed using Delis-Kaplan Executive Function System Trails and Verbal Fluency Switching
Associative Memory	Baseline, 4 weeks, and 8 weeks	Measured using NIH Toolbox Face Name Associative Memory Exam and Face Name Associative Memory Exam Delay tests
Attention	Baseline, 4 weeks, and 8 weeks	Assessed using Wechsler Adult Intelligence Scale - IV and Rey Auditory Verbal Learning Test Trial 1.
Problem-Solving	Baseline, 4 weeks, and 8 weeks	Assessed using NIH Toolbox Visual Reasoning

Trial Locations

Locations (1)

Georgia State University; 🇺🇸 Atlanta, Georgia, United States