Effect of blueberry intervention on endothelial function: a systematic review and meta-analysis
What this study found
Blueberry intake improved endothelial function overall. The pooled evidence showed significant benefits for flow-mediated dilation and reactive hyperemia index, and blueberry consumption also reduced diastolic blood pressure. There was no significant effect on systolic blood pressure or lipid measures, including HDL-C and LDL-C, although smokers appeared to show notable blood pressure reductions in subgroup analysis. The authors concluded that larger trials are needed to confirm mechanisms and clarify effects in specific subpopulations.
- Study & population
- Systematic review and meta-analysis of 11 intervention studies involving 400 participants across the United States, United Kingdom, and Italy.
- Intervention
- Blueberry consumption was evaluated in multiple forms, including freeze-dried blueberry powder (13 g to 45 g, with several trials using 22 g, 26 g, or 300 g of blueberry), a blueberry polyphenol drink containing 766 mg total blueberry polyphenols, and fresh blueberry-equivalent doses.
- Key limitation
- The evidence base was small and heterogeneous, with wide variation in blueberry form, dose, and intervention duration, including both acute and chronic studies.
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Open PDFOriginal abstract
Introduction: Endothelial dysfunction indicates blood vessel injury and is a risk factor for cardiovascular diseases. Blueberry has been approved for its benefits on human health, especially on cardiovascular function. However, its effect on endothelial function remains unclear. We conducted a systematic review and meta-analysis to explore the impact of blueberries on endothelial function in adults. Methods: We searched PubMed, Web of Science, Embase, and the Cochrane Library, 16 studies were included in the systematic review, and 11 were used for the meta-analysis. Data associated with endothelial function were extracted and pooled as mean differences (MD) with 95% confidence intervals (CI). Results: Blueberry consumption significantly improved flow-mediated dilation (FMD) by 1.50% (95% CI: 0.81, 2.20; I2 = 87%) and reactive hyperemia index (RHI) by 0.26 (95% CI: 0.09, 0.42; I2 = 72%). A significant decrease in diastolic blood pressure (DBP) was also observed (MD: −2.20 mm Hg; 95% CI: −4.13, −0.27; I2 = 11%). Subgroup analysis indicated a significant decrease in blood pressure (Systolic blood pressure [SBP]: −3.92 mmHg; 95% CI: −6.88, −0.97; I2 = 20% and DBP: −2.20 mmHg; 95% CI: −4.13, −0.27; I2 = 11%) in the smoking population. However, SBP levels (MD: −1.43 mm Hg; 95% CI: −3.11, 0.26; I2 = 20%) and lipid status (high-density lipoprotein cholesterol [HDL-C]: 0.06; 95% CI: −0.04, 0.16; I2 = 77%; low-density lipoprotein cholesterol [LDL-C]: 0.05; 95% CI: −0.14, 0.24; I2 = 0%) did not significantly improve. Conclusion: Blueberry intervention improved endothelial function and DBP. Subgroup analysis revealed a notable improvement in blood pressure among the smoking population. However, no significant effects were observed on SBP, HDL-C, and LDL-C levels. Future research should delve into the mechanisms of endothelial improvement and verify blood pressure reduction in specific subpopulations through large-scale trials. Clinical Trial Registration: https://www.crd.york.ac.uk/PROSPERO/, Identifier CRD42023491277.