Effect of 7-day dietary supplementation with grape seed extract on cardiac autonomic and hemodynamic responses in elevated and stage 1 hypertension.

2025-05
Clinical physiology and functional imaging 45(3)
- Albert Lira
- William Boyer
- Trevor Gillum
- Sean Sullivan
- Jong-Kyung Kim

PubMed: 40341867
DOI: 10.1111/cpf.70010

Study Design

Type: Randomized Controlled Trial (RCT)
Population: Ten males
Methods: double-blinded, cross-over design, GSE or placebo supplementation with a 1-week wash-out period
Blinding: Double-blind
Duration: 7 days

Backgrounds

Evidence indicated that an increase in nitric oxide (NO) bioavailability via dietary supplementation decreased sympathetic output. Grape seed extract (GSE) supplement has been known to increase NO production and improve endothelial function in individuals with elevated and stage 1 hypertension (ES1H), but no studies have assessed the effects of this extract on autonomic balance. Accordingly, the aim of the study was to investigate the effect of 7 days of dietary GSE supplementation on cardiac autonomic and hemodynamic responses.

Methods

Ten males were recruited in this study. Each subject received GSE or placebo supplementation with a 1-week wash-out period. In a double-blinded, cross-over design, hemodynamic responses (heart rate (HR), stroke volume (SV), cardiac output (CO), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean atrial pressure (MAP)), heart rate variability (HRV), and cold pressor test (CPT) were compared before and after either GSE or placebo supplementation.

Results

Our results indicated that GSE decreased resting DBP (75 ± 2 vs. 71 ± 3) and MAP (91 ± 2 vs. 88 ± 3) compared to the placebo (DBP:71 ± 3 vs. 74 ± 3; MAP: 89 ± 2 vs. 90 ± 2). However, MAP responses to CPT had no difference between post-PL and post-GSE supplementation when expressed as absolute increases (PL, Δ10.3 ± 1 mmHg, GSE, Δ9.1 ± 1 mmHg). There were no differences on the HR, SV, CO, SBP, and HRV between placebo and GSE treatments.

Conclusions

Our study suggests that GSE can be used as a dietary nutraceutical capable of reducing blood pressure and the risk of ES1H development. The reduction of blood pressure occurs via peripheral vasodilation, not associated with cardiac autonomic reactivity.

Research Insights

Red Grape→Reduced Cardiac Output
There were no differences on the CO … between placebo and GSE treatments
Effect
Neutral
Effect size
Small
Red Grape→Reduced Diastolic Blood Pressure
GSE decreased resting DBP (75 ± 2 vs. 71 ± 3) compared to the placebo (DBP:71 ± 3 vs. 74 ± 3)
Effect
Beneficial
Effect size
Moderate
Red Grape→Reduced Heart Rate
There were no differences on the HR … between placebo and GSE treatments
Effect
Neutral
Effect size
Small
Red Grape→Reduced Heart Rate Variability
There were no differences on the HRV … between placebo and GSE treatments
Effect
Neutral
Effect size
Small
Red Grape→Reduced Mean Arterial Pressure
GSE decreased resting MAP (91 ± 2 vs. 88 ± 3) compared to the placebo (MAP: 89 ± 2 vs. 90 ± 2)
Effect
Beneficial
Effect size
Small
Red Grape→Reduced Mean Arterial Pressure Response to Cold Pressor Test
MAP responses to CPT had no difference between post-PL and post-GSE supplementation when expressed as absolute increases (PL, Δ10.3 ± 1 mmHg, GSE, Δ9.1 ± 1 mmHg)
Effect
Neutral
Effect size
Small
Red Grape→Reduced Stroke Volume
There were no differences on the SV … between placebo and GSE treatments
Effect
Neutral
Effect size
Small
Red Grape→Reduced Systolic Blood Pressure
There were no differences on the SBP … between placebo and GSE treatments
Effect
Neutral
Effect size
Small