Background: Recent studies suggest the positive role of flavonols on blood pressure (BP) values, although there are not many conducted on humans. The aim of this study was to examine the relationship between flavonol intake and their main sources of consumption, and systolic (SBP) and diastolic (DBP) BP values in coronary artery disease (CAD) patients. Methods and results: forty CAD patients completed a food-frequency questionnaire dedicated to flavonol-intake assessment. The analysis revealed significant correlation between isorhamnetin intake and SBP values—absolute (R: −0.36; 95% CI: −0.602 to −0.052; p = 0.02), and related to body mass (R: −0.38; 95% CI: −0.617 to −0.076; p = 0.02. This effect was observed in male participants (R: −0.65; 95% CI: −0.844 to −0.302; p = 0.001 and R: −0.63; 95% CI: −0.837 to −0.280; p = 0.002 respectively), but not in female patients. The main contributors were onions, tomatoes, blueberries, apples, tea, coffee and wine. White onion (R: −0.39; 95% CI: −0.624 to −0.088; p = 0.01) consumption was inversely correlated with SBP, and tomato consumption (R: −0.33; 95% CI: −0.581 to −0.020; p = 0.04) with DBP. The comparison between patients with BP < 140 mmHg and ≥140 mmHg revealed significant differences in white onion (p = 0.01) and blueberry (p = 0.04) intake. Conclusions: This study revealed the relationship between long-term dietary isorhamnetin intake and SBP values. The analysis of specific food intake showed that onion, tomato and blueberry consumption could impact BP values. This may suggest that a dietary approach which includes a higher intake of isorhamnetin-rich products could possibly result in BP lowering in CAD patients.
Keywords: blood pressure; flavonols; hypertension; isorhamnetin; quercetin.