Effects of cognac on coronary flow reserve and plasma antioxidant status in healthy young men

Abstract

Background: The cardioprotective effects of certain alcoholic beverages are partly related to their polyphenol content, which may improve the vasodilatory reactivity of arteries. Effect of cognac on coronary circulation, however, remains unknown. The purpose of this randomized controlled cross-over study was to determine whether moderate doses of cognac improve coronary reactivity as assessed with cold pressor testing (CPT) and coronary flow reserve (CFR) measurement.

Methods: Study group consisted of 23 subjects. Coronary flow velocity and epicardial diameter was assessed using transthoracic echocardiography at rest, during CPT and adenosine infusion-derived CFR measurements before drinking, after a moderate (1.2 +/- 0.1 dl) and an escalating high dose (total amount 2.4 +/- 0.3 dl) of cognac. To explore the bioavailability of antioxidants, the antioxidant contents of cognac was measured and the absorption from the digestive tract was verified by plasma antioxidant capacity determination.

Results: Serum alcohol levels increased to 1.2 +/- 0.2 per thousand and plasma antioxidant capacity from 301 +/- 43.9 micromol/l to 320 +/- 25.0 micromol/l by 7.6 +/- 11.8%, (p = 0.01) after high doses of cognac. There was no significant change in flow velocity during CPT after cognac ingestion compared to control day. CFR was 4.4 +/- 0.8, 4.1 +/- 0.9 (p = NS), and 4.5 +/- 1.2 (p = NS) before drinking and after moderate and high doses on cognac day, and 4.5 +/- 1.4, and 4.0 +/- 1.2 (p = NS) on control day.

Conclusion: Cognac increased plasma antioxidant capacity, but it had no effect on coronary circulation in healthy young men.

Trial registration: NCT00330213.

Figures

Figure 1

Study protocol. The subjects ingested two escalating doses of cognac (one dose 1.2 ± 0.1 dl). Each dose of cognac contained ethanol 0.5 mg/kg, and accordingly, the full dose of ethanol was 1.0 g/kg. CFR was measured 30 min after each dose. As a control, CFR was measured in randomized cross-over design without beverage ingestion twice.

Figure 2

Epicardial coronary artery (LAD) diameter at baseline, during cold pressor test and adenosine infusion.

Figure 3

Coronary flow velocity in the LAD obtained using pulsed-wave Doppler at baseline, during cold pressor test (CPT) and adenosine infusion.

Figure 4

Individual changes in coronary flow velocity reserve (CFR) before cognac [before], after a moderate dose (ethanol 0.5 g/kg) [dose1] and a high dose (ethanol 1.0 g/kg) [dose2]. Control 1 corresponds to the first measurement on a control day. Control 2 corresponds to the measurement carried out 2 h after Control 1.

Figure 5

Individual changes in hyperemia to baseline ratio of flow velocity in cold pressor test (CPT). before cognac [before], after a moderate dose (ethanol 0.5 g/kg) [dose1] and a high dose (ethanol 1.0 g/kg) [dose2]. Control 1 corresponds to the first measurement on a control day. Control 2 corresponds to the measurement carried out 2 h after Control 1.

Figure 6

Effects of cognac on rate pressure product. No significant changes were detected in the corresponding values at rest, during CPT or CFR measurement before drinking, after moderate and high doses, respectively. 0 = before drinking; Mod = moderate dose; High = high dose.