(P29-014-24) Identifying Factors Contributing to Endothelial Function Responses to Chronic Blueberry Consumption in Postmenopausal Women With Above-Normal Blood Pressure

Objectives: We recently demonstrated that chronic blueberry consumption improved endothelial function in postmenopausal women with above-normal blood pressure, but that there was inter-individual variability in the direction and magnitude of endothelial function responses. The objective of this secondary analysis was to identify potential factors influencing endothelial function responses to blueberry consumption.

Methods: Data were collected from the treatment group (n = 17; 22 g/day freeze-dried blueberry powder for 12 weeks) in a randomized, double-blind, placebo-controlled, parallel-arm trial in postmenopausal women aged 45-65 years with elevated blood pressure or stage 1-hypertension. Participants were grouped as responders (n = 8; ≥ +1% change in flow-mediated dilation (FMD) from baseline to 12 weeks) or non-responders (n = 9; < +1% change from baseline). Previously assessed outcomes from the clinical trial were evaluated.

Results: At baseline, responders had lower high-density lipoprotein cholesterol (p = 0.008) and higher low-density lipoprotein cholesterol (p = 0.027) and estradiol (p = 0.002) concentrations, the latter was positively correlated with the change in FMD from baseline to 12 weeks (p = 0.002). Responders had lower baseline FMD (p = 0.031), and higher oxidative stress-mediated suppression of FMD (p = 0.023) and intracellular adhesion molecule-1 (p = 0.010) concentrations compared to non-responders. At 12 weeks, biopsied endothelial cell phosphorylated endothelial nitric oxide synthase expression was higher for responders compared to non-responders (p = 0.019). Plasma nitrate concentrations were lower at 4 (p = 0.048) and 12 (p = 0.028) weeks for responders than non-responders. Differences in 5 (poly)phenol metabolites were noted between groups at various time points (p < 0.05). Responders and non-responders had distinct baseline gut microbial communities and responders were characterized by lower microbial richness (p < 0.001).

Conclusions: These findings suggest baseline factors influence endothelial function responses to blueberry consumption. Next steps include identifying biological and/or environmental factors predictive of treatment response.

Funding Sources: US Highbush Blueberry Council and USDA National Institute of Food and Agriculture [grant no. 2020-67017-30833/project accession no. 1021875].