Blueberries for High Blood Pressure

(WB2020 Trial)

Overseen By Sarah A Johnson, PhD, RDN

Age: 18+

Sex: Male

Trial Phase: Phase 1 & 2

Sponsor: Colorado State University

Must not be taking: Lipid-lowering, Glucose-lowering

Disqualifiers: Cancer, Cardiovascular, Diabetes, others

Compensation: Varies

Number of Visits: Unknown

Duration: 12 weeks

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores whether blueberry powder can help lower blood pressure and improve artery health in individuals with mild high blood pressure. Researchers aim to understand how blueberries might reduce stress and inflammation, factors linked to heart disease. Participants will consume either blueberry powder or a placebo daily. Men and postmenopausal women aged 45 to 70 with elevated blood pressure or mild hypertension, but without major health issues like diabetes or heart disease, are suitable candidates for this study. As a Phase 1 trial, the research focuses on understanding how the treatment works in people, offering participants a chance to be among the first to explore its potential benefits.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications, but you cannot participate if you are taking more than one blood pressure medication, taking it more than once a day, or have been on it for less than three months. Also, you cannot be on any lipid-lowering or glucose-lowering medications.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that blueberry powder might offer health benefits, but its effect on blood pressure remains unclear. Some studies suggest that blueberries can improve blood vessel function, benefiting heart health. However, strong evidence is lacking to confirm that blueberry supplements lower blood pressure in individuals with hypertension.

Regarding safety, consuming blueberries is generally safe, and no serious side effects from blueberry powder have been reported. As the trial begins, the primary goal is to ensure the treatment's safety for participants. Serious side effects are unlikely, but researchers will monitor to ensure it is well-tolerated. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising for high blood pressure?

Unlike the standard medications for high blood pressure, which often include drugs like ACE inhibitors, beta-blockers, and diuretics, this treatment utilizes blueberry powder as its active ingredient. Researchers are excited because blueberries are rich in natural compounds called polyphenols, which have shown potential in improving blood vessel function and reducing blood pressure. This treatment offers a more natural alternative with fewer side effects, and it taps into the antioxidant properties of blueberries, which could provide additional health benefits beyond just managing blood pressure.

What evidence suggests that blueberries might be an effective treatment for high blood pressure?

Research has shown that blueberries might help lower blood pressure. In one study, participants who consumed blueberry powder daily for 12 weeks saw their top blood pressure number drop by about 3.59 points compared to those who didn't. This trial will test the effects of blueberry powder, with participants in the blueberry arm receiving 22 g of blueberry powder per day. Another study found that blueberries improved blood vessel function by 0.85%. These findings suggest that blueberries could help manage blood pressure and support heart health. ^{1 3 6 7 8}

Are You a Good Fit for This Trial?

This trial is for men aged 45-70 and postmenopausal women with elevated blood pressure or stage 1 hypertension. Participants must be able to consent, not have had cancer, cardiovascular disease, diabetes, or certain other health conditions. They shouldn't be on multiple antihypertensive drugs or recent smokers.

Inclusion Criteria

I am a man or a postmenopausal woman aged between 45 and 70.

Your blood pressure is too high.

Ability to provide informed consent

Exclusion Criteria

I have been diagnosed with cancer or a major organ disease.

I have been on hormone replacement therapy for the last 6 months.

I am a current smoker or have smoked in the last year.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive 22 g of blueberry or placebo powder daily to assess the efficacy of blueberries in reducing blood pressure and improving vascular endothelial dysfunction and arterial stiffness

12 weeks

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Blueberry Powder
• Placebo Powder

Trial Overview The study tests if blueberry powder can lower blood pressure and improve vascular health compared to a placebo in middle-aged/older individuals with high blood pressure. It aims to see if the antioxidants in blueberries help reduce oxidative stress and inflammation.

How Is the Trial Designed?

Group I: Blueberry Experimental Treatment 1 Intervention

22 g blueberry powder per day

Group II: Control Placebo Group 1 Intervention

22 g placebo control powder per day

Who Is Running the Clinical Trial?

Colorado State University

Lead Sponsor

Trials

138

Recruited

38,200+

Wild Blueberry Association of North America

Collaborator

Trials

7

Recruited

340+

Wild Blueberry Association of North America

Collaborator

Trials

3

Recruited

100+

Published Research Related to This Trial

In a study involving 37 young adults, both whole blueberries and freeze-dried blueberry powder did not show significant differences in improving cardiovascular health compared to a control group, indicating that the form of blueberry may not matter for cardiovascular benefits.

However, both blueberry treatments improved plasma nitrite levels significantly compared to baseline, suggesting a potential positive effect on vascular function, even though other cardiovascular risk factors like blood pressure and cholesterol levels did not show significant changes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of Blueberry Consumption on Cardiovascular Health in Healthy Adults: A Cross-Over Randomised Controlled Trial. Wang, Y., Gallegos, JL., Haskell-Ramsay, C., et al.[2022]

A systematic review of 17 randomized clinical trials found that blueberry and cranberry supplementation had neutral effects on blood pressure (BP) in patients with cardiometabolic diseases, showing no significant reductions in systolic BP (SBP) or diastolic BP (DBP).

Despite some studies indicating potential benefits, the pooled results revealed only minor, statistically non-significant reductions in BP, highlighting the need for further high-quality research to confirm any clinical efficacy.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The effects of blueberry and cranberry supplementation on blood pressure in patients with cardiovascular diseases: A systematic review and meta-analysis of randomized clinical trials. Delpino, FM., Dos Santos, FS., Flores, TR., et al.[2023]

Daily consumption of blueberries for 6 weeks significantly increased natural killer (NK) cell counts in participants, suggesting an enhancement of immune function.

Blueberry intake also led to reductions in augmentation index (AIx) and aortic systolic pressures (ASPs), indicating potential cardiovascular benefits, particularly in individuals with prehypertensive blood pressure levels.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Six weeks daily ingestion of whole blueberry powder increases natural killer cell counts and reduces arterial stiffness in sedentary males and females. McAnulty, LS., Collier, SR., Landram, MJ., et al.[2022]

Feeding flavonoid-rich blueberries to spontaneously hypertensive stroke-prone rats significantly lowered their blood pressure by inhibiting angiotensin-converting enzyme (ACE) activity, which was elevated in these rats compared to normotensive rats.

After 2 weeks on a blueberry diet, ACE activity in the hypertensive rats decreased, and this effect persisted for up to 6 weeks, suggesting that blueberries could be a beneficial dietary intervention for managing early hypertension.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Feeding blueberry diets inhibits angiotensin II-converting enzyme (ACE) activity in spontaneously hypertensive stroke-prone rats. Wiseman, W., Egan, JM., Slemmer, JE., et al.[2022]

Current clinical evidence suggests that while there is no direct blood pressure lowering effect from dietary berry consumption, certain berries may help normalize blood pressure in individuals who are already hypertensive.

The review highlights the potential role of specific berry polyphenols, such as anthocyanins and ellagic acid, in influencing blood pressure regulation, although results are mixed and complicated by confounding factors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Role of Berry Consumption on Blood Pressure Regulation and Hypertension: An Overview of the Clinical Evidence. Vendrame, S., Adekeye, TE., Klimis-Zacas, D.[2022]

Wild blueberry powder retains a significant amount of its health-promoting anthocyanins in ice pops and refrigerated juice, with both products maintaining over 90% of their initial anthocyanin content after 8 weeks of storage.

The stability of polyphenolic compounds varies by product, with gummies showing much lower retention of anthocyanins (43-51%) compared to other formulations, likely due to gel hardening affecting extraction efficiency at lower temperatures.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Changes in Polyphenolics during Storage of Products Prepared with Freeze-Dried Wild Blueberry Powder. Lavefve, L., Brownmiller, C., Howard, L., et al.[2020]

Citations

1. clinicaltrials.gov clinicaltrials.gov/study/NCT06735599

Wild Blueberries for Gut, Brain, and Heart Health in Adults ... The purpose of the study is to determine the effectiveness of wild blueberries on cardiovascular health, cognitive function, and gut microbiota composition in ...

2. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10315404/

Wild blueberry (poly)phenols can improve vascular function ... We observed that 12 wk daily WBB consumption improved FMD by 0.85% and ambulatory systolic BP decreased by −3.59 mmHg with respect to the control, whereas no ...

3. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8130140/

An 8-week freeze-dried blueberry supplement impacts ... Blueberry supplementation has previously been associated with favorable effects on blood pressure [11, 12], some aspects of brain cognitive function [13, 14] ...

4. mdpi.com mdpi.com/2072-6643/14/13/2562

Effects of Blueberry Consumption on Cardiovascular ... We found that increasing daily blueberry consumption to 160 g/d or the equivalent blueberry powder in healthy adults for 1 week did not influence blood pressure ...

5. healthline.com healthline.com/health-news/how-wild-blueberries-may-help-lower-blood-pressure-and-boost-your-brain

Want to Lower Your Blood Pressure? Wild Blueberries ... People who consumed a drink made out of freeze-dried wild blueberry powder once a day for 12 weeks saw a reduction in their systolic blood ...

6. webmd.com webmd.com/vitamins/ai/ingredientmono-1013/blueberry

Blueberry - Uses, Side Effects, and More High blood pressure. Eating freeze-dried blueberries or taking blueberry powder by mouth doesn't lower blood pressure in people with high blood pressure or ...

7. sciencedirect.com sciencedirect.com/science/article/abs/pii/S0965229920302934

Blueberry and cardiovascular disease risk factors Conclusion. Current evidence is insufficient to show a benefit of blueberry supplements in modifying CVD risk factors across a variety of adult populations.

8. verywellhealth.com verywellhealth.com/blueberry-extract-89424

Blueberry Extract Benefits and Precautions 7. Another study found that six weeks of daily blueberry consumption didn't improve blood pressure. 8 However, it did improve endothelial function.