Dallas, TX - Results of randomized crossover study in normotensive men showed that, regardless of whether it was beer or red wine, alcohol consumption increased systolic blood pressure as well as heart rate in these men, undermining the idea that polyphenols in red wine can mitigate alcohol's BP-elevating effects.

The report is published online April 18, 2005 and will appear in the May 2005 issue of Hypertension: Journal of the American Heart Association.[1]

"The advice to drinking men 'at risk' of hypertension and those with hypertension is to drink fewer than two drinks per day," lead author Dr Renate R Zilkens (School of Medicine and Pharmacology, Royal Perth Hospital, Australia) said in a press statement from the AHA. "At that level they will still benefit from the HDL-cholesterol-raising effect and anticoagulant properties of alcohol."

A positive relationship between alcohol consumption and blood pressure is well established, the authors write, but the relative effects of specific alcoholic beverages is controversial. Some human studies have suggested improvements in flow-mediated dilation (FMD), impairment of which is considered a marker of endothelial dysfunction, with consumption of purple grape juice and dealcoholized red wine. Although most of these studies were uncontrolled, Zilkens et al note, they have been interpreted as supporting the hypothesis that vasodilator antioxidant polyphenols found in red wine and grape juice may be beneficial for endothelial function.

In this study, the researchers aimed to determine whether red wine had less of an impact on blood pressure compared with beer, possibly because of its high content of antioxidant polyphenolic compounds. They also included dealcoholized red wine to assess whether it might have less of an effect on BP because of the high content of polyphenolic compounds, without the influence of alcohol.

Twenty-four healthy, nonsmoking, normotensive men participated in a four-period crossover study comparing four weeks of abstinence with the same period of daily consumption of red wine (375 mL, 39 g of alcohol), dealcoholized wine (375 mL), or beer (1125 mL, 41 g of alcohol). The researchers then assessed effects on ambulatory systolic and diastolic blood pressure, heart rate, and FMD and glyceryl trinitrate-mediated dilatation (GTNMD) of the brachial artery, measures of endothelial function.

Zilkens et al report no differences in blood pressure and heart rates in the men during abstinence and when consuming the dealcoholized red wine. However, both beer and red wine consumption significantly increased 24-hour systolic blood pressure, mostly when subjects were awake, as well as their heart rate while asleep.

They saw no specific effects of any of the three beverages—red wine, dealcoholized red wine, or beer—on FMD or GTNMD, suggesting that the polyphenols in the red wine did not have a significant effect in mitigating the BP-elevating effects of the alcohol, they point out.

The predominant blood-pressure-elevating effect was seen during the day, and the predominant acceleration of heart rate was seen during the night, immediately after the ingestion of the alcohol, most of which took place in the evening, they point out. "It appears likely that the ability of alcohol beverages to raise BP is caused by the alcohol," they conclude.