Acute effects of beer on endothelial function and hemodynamics: a single-blind, crossover study in healthy volunteers

OBJECTIVE

Moderate consumption of beer is associated with lower cardiovascular (CV) risk. The goal of this study was to determine the effect of beer consumption on CV risk. To explore the underlying mechanisms, we studied the acute effects of the constituents of beer (alcohol and antioxidants), on established predictors of CV risk: endothelial function, aortic stiffness, pressure wave reflections and aortic pressure.

METHODS

In a randomized, single-blind, crossover study, 17 healthy, non-smoking, men (ages 28.5 ± 5.2 y with body mass index 24.4 ± 2.5 kg/m(2)) consumed on three separate occasions, at least 1 wk apart: 1. 400 mL of beer and 400 mL water, 2. 800 mL of dealcoholized beer (same amount of polyphenols as in the 400 mL of beer), and 3. 67 mL of vodka and 733 mL water (same amount of alcohol as in the 400 mL of beer). Each time aortic stiffness (pulse wave velocity), pressure wave reflections (AΙx), aortic and brachial pressure (Sphygmocor device), and endothelial function (brachial flow mediated dilatation) were assessed at fast and 1 and 2 h postprandial.

RESULTS

Aortic stiffness was significantly and similarly reduced by all three interventions. However, endothelial function was significantly improved only after beer consumption (average 1.33%, 95% confidence interval [CI] 0.15-2.53). Although wave reflections were significantly reduced by all three interventions (average of beer: 9.1%, dealcoholized beer: 2.8%, vodka 8.5%, all CI within limits of significance), the reduction was higher after beer consumption compared with dealcoholized beer (P = 0.018). Pulse pressure amplification (i.e., brachial/aortic) was increased by all three test drinks.

CONCLUSIONS

Beer acutely improves parameters of arterial function and structure, in healthy non-smokers. This benefit seems to be mediated by the additive or synergistic effects of alcohol and antioxidants and merits further investigation.

A study of the antioxidant properties of beers using electron paramagnetic resonance

The antioxidant properties of various kinds of beers were investigated using electron paramagnetic resonance (EPR) spectroscopy. This was possible by measuring the changes in the intensity of the EPR spectrum that resulted from the interaction of the stable radical DPPH (1,1-diphenyl-2-picrylhydrazyl) with the antioxidants found in a beer sample. The antioxidant capacity was then presented in Trolox Equivalents, e.g. μM trolox in a beer sample of 100ml. The influence of the type, colour, the content of the extract and alcohol on the antioxidant activities of commercial beer samples was investigated using two-way hierarchical clustering and analysis of variance. The results showed that all of the beers investigated exhibit antioxidant properties. By performing an analysis of variance, it was found that the value of the antioxidant capacity significantly (0.05 level of significance) depends on the content of the extract and the colour of the beer. It seems that additives also influence the antioxidant properties to some extent, but neither the alcohol content nor the kind of fermentation affects the antioxidant properties of beer.

Evaluation of different validation strategies and long term effects in NIR calibration models

Stable and reliable NIR calibration models for the barley malt quality assessment were developed and exhaustively evaluated. The measured parameters are: fine extract, fermentability, pH, soluble nitrogen, viscosity, friability and free-amino nitrogen. The reliability of the developed calibration models was evaluated comparing the classic leave-one-out internal validation with a more challenging one exploiting re-sampling scheme. The long-term effects, intended as possible alterations of the NIR method predictive power, due to the variation between samples collected in different years, were evaluated through an external validation which demonstrated the stability of the developed calibration models. Finally, the accuracy and the precision of the developed calibration models were evaluated in comparison with the reference methods. This exhaustive evaluation offers a realistic idea of the developed NIR methods predictive power for future unknown samples and their application in the beer industry.

Contribution of monophenols to beer flavour based on flavour thresholds, interactions and recombination experiments

Although monophenols are known to contribute to the flavour of many foods and beverages, little is known about their influence on beer flavour. Therefore, the contribution of 11 monophenols to the overall beer flavour was studied by determining their flavour thresholds. Large differences in sensitivity were observed between individual tasters. Next, flavour interactions between monophenols were examined in nine binary mixtures, which showed that strong interactions like synergy and antagonism occur. Based on these results, the flavour contribution of the monophenols was estimated by calculating flavour units. These proved to be rather low for most of the studied monophenols. However, recombination experiments demonstrated that monophenols enriched beer flavour with spicy, smokey and vanilla flavour aspects. This showed how monophenols might influence overall flavour, even at sub-threshold concentrations.

Association of drinking patterns and health characteristics with beverage preference

PURPOSES

To investigate the association between the type of preferred alcoholic beverage and drinking pattern and health characteristics.

METHODS

A Cross-sectional study was conducted from 22 April to 3 May in 2002. 301 females and 699 males aged 13 to 59 were personally interviewed. Data on sociodemographic characteristics, drinking pattern and health characteristics were collected. 735 drinkers who were 19 year-old or over were included in analysis. Beverage preference was classified 3 categories: Beer drinker, wine drinker (including wine, makguly, chungju and yakju) and soju drinker (including soju and spirits).

RESULTS

Beer drinkers were likely to be females. Compared to wine or soju drinkers, beer drinkers were less frequently drank, and consumed less total alcohol per week and less alcohol per 1 drinking among both male and female. Controlling for various confounders, beer drinker had significantly less total alcohol consumption per week, and alcohol consumption per 1 drinking than wine and soju drinker.

CONCLUSIONS

Beer drinking were associated with less smoking in males and healthy drinking pattern in both gender than soju drinking.