Última actualización 8 de julio de 2026
Key finding
Intervention with bilberry and grape seed extract decreased systolic blood pressure by 4.7 mmHg (p < 0.001).
This study investigated the effects of long-term bilberry and grape seed extract supplementation on blood pressure in individuals at risk of type 2 diabetes mellitus (T2DM). It found significant reductions in systolic and diastolic blood pressure.
Quick read
The essential study design details in one scan.
EvidenceScore™
Moderate
Study type
RCTs
Follow-up
Medium-Term (3–12 mo)
Risk of bias
Some Concerns
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Plain-language summary
A plain-language read of the study’s main message and where it applies.
Study focus
This study investigated the effects of long-term bilberry and grape seed extract supplementation on blood pressure in individuals at risk of type 2 diabetes mellitus (T2DM). It found significant reductions in systolic and diastolic blood pressure.
Managing blood pressure is crucial for individuals at risk of T2DM, as hypertension can lead to serious cardiovascular complications. The significant reductions in blood pressure observed in this study suggest that bilberry and grape seed extract may offer a natural dietary approach to improve cardiovascular health in this population, potentially reducing the risk of diabetes-related complications.
The study did not assess long-term effects beyond the intervention period. Sample size and demographic diversity may limit generalizability. Lack of significant changes in other metabolic markers raises questions about broader efficacy.
Published in
Publication details and source links for this paper.
Teresa G, Alan WW, Wendy RR, et al. Long-term supplementation with bilberry and grape seed extract can improve blood pressure in individuals at risk of T2DM. Frontiers in Nutrition. 2023;10:1139880. doi:10.3389/fnut.2023.1139880
Systolic blood pressure decreased by 4.7 mmHg (p < 0.001).
Diastolic blood pressure decreased by 2.3 mmHg (p = 0.0009).
No significant effects on fasting HbA1c, fasting plasma glucose, or cholesterol levels.
Evidence network
Understand where this research contributes within the broader evidence network.
This study contributes evidence to Bilberry extract and 2-hour plasma glucose, Advanced glycation end products (AGEs), Diastolic blood pressure, and 10 more.
This study contributes evidence to
Primary intervention
Bilberry extract
Primary outcomes
Primary intervention
Intervention and outcome relationships this study adds to the evidence network.
Editorial context
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Evidence network role
This section describes how the study fits into the current evidence network. It does not determine whether an intervention works on its own.
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Related topics
13
Evidence pairs
1777
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Contributes evidence
Evidence topic
Contributes evidence
Evidence topic
Contributes evidence
Evidence topic
Contributes evidence
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Evidencia principal
Tema de evidencia
matched_outcome
Evidencia relacionada
Tema de evidencia
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Core evidence
The primary outcomes reported in this study.
Bilberry extract → 2-hour plasma glucose
Bilberry extract → 2-hour plasma glucose
Bilberry extract → Advanced glycation end products (AGEs)
Bilberry extract → Advanced glycation end products (AGEs)
Bilberry extract → Diastolic blood pressure
Bilberry extract → Diastolic blood pressure
Bilberry extract → Fasting Plasma Glucose (FPG)
Bilberry extract → Fasting Plasma Glucose (FPG)
Bilberry extract → Fecal levels of phenolic metabolites
Bilberry extract → Fecal levels of phenolic metabolites
Bilberry extract → gut microbiota composition
Bilberry extract → gut microbiota composition
Bilberry extract → Systolic blood pressure
Bilberry extract → Systolic blood pressure
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Relationships organized using the Dediabetes Evidence Intelligence™ framework.
This study contributes to evidence on Bilberry extract and HbA1c, Bilberry extract and Postprandial and OGTT Glucose.
This study contributes to the evidence on the following intervention-outcome relationships.
Supplements
Supplements
Curated evidence collections and hubs this study is part of.
All studies on Bilberry extract
Contributes to Bilberry extract evidence base.
All studies measuring HbA1c
Measures HbA1c as a key outcome.
All studies measuring Blood Pressure
Measures Blood Pressure as a key outcome.
All studies measuring Postprandial and OGTT Glucose
Measures Postprandial and OGTT Glucose as a key outcome.
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2 results
1 results
2 results
2 results
1 results
Generated from the study's connected evidence using Evidence Intelligence™.
Bilberry extract may lower HbA1c.
ConsistencyScore™: Results are mixed and should be interpreted cautiously.
Ranked evidence signals
HbA1c
EvidenceScore™ Moderate | EvidenceScore™ 69.0 | moderate positive | ConsistencyScore™ Mixed | 1 study
Why this answer: This answer is cautious because the available studies report mixed findings.
Limitations
Bilberry extract appears to improve diastolic blood pressure.
ConsistencyScore™: Consistency cannot yet be determined from the available evidence.
Ranked evidence signals
Diastolic blood pressure
EvidenceScore™ Emerging | EvidenceScore™ 59.0 | strong positive | ConsistencyScore™ Unclear | 1 study
Why this answer: This answer is based on a single supporting study.
Limitations
Bilberry extract appears to improve systolic blood pressure.
ConsistencyScore™: Consistency cannot yet be determined from the available evidence.
Ranked evidence signals
Systolic blood pressure
EvidenceScore™ Emerging | EvidenceScore™ 59.0 | strong positive | ConsistencyScore™ Unclear | 1 study
Why this answer: This answer is based on a single supporting study.
Limitations
Current evidence does not show a clear benefit of Bilberry extract for 2-hour plasma glucose.
ConsistencyScore™: Consistency cannot yet be determined from the available evidence.
Ranked evidence signals
2-hour plasma glucose
EvidenceScore™ Emerging | EvidenceScore™ 59.0 | neutral | ConsistencyScore™ Unclear | 1 study
Why this answer: This answer is based on a single supporting study.
Limitations
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