Page last updated: Tuesday, March 13, 2007
Medically, is wine just another alcoholic beverage?
– revisited by Creina Stockley, The Australian Wine Research Institute
All alcoholic beverages have the ability to reduce the risk of all-cause mortality by approximately 20 to 50 percent, when consumed in moderation. This ability has been demonstrated by extensive epidemiological studies, which have been undertaken in men and women, for different age groups, and for different nationalities or populations.

Some of these studies have also considered the alcoholic beverage consumed and the reduction in risk of, for example, cardiovascular disease. From these studies it can be concluded that the alcohol component, which is common to all the beverage types, does confer a benefit. This benefit is considered to be, primarily, an increase in the plasma concentration of high density lipoprotein (HDL) cholesterol, where a low plasma concentration of HDL is correlated with a high risk of cardiovascular disease. HDL transports dietary-derived cholesterol from the arteries and body organs and tissues to the liver, where it is removed from the body. In addition, alcohol decreases blood clotting by reducing the ability of the blood cells to aggregate and clot together, and also by increasing their ability to de-aggregate once blood clots have formed in arteries and veins.

Particular prospective epidemiological studies have indicated that consumers of wine have a greater reduction in the risk of cardiovascular disease than consumers of beer or spirits. The reduction in risk was similar to that for consumers of certain fruits, grains and vegetables, where the linkage between wine and these foodstuffs is their concentration of phenolic compounds.Phenolic compounds, such as flavonols, phenolic acids and their esterified derivatives, are purported to act as antioxidants. Another risk factor for cardiovascular disease is a high plasma concentration of low density lipoprotein (LDL) cholesterol. In its oxidised form, LDL accumulates on arterial walls and if not removed, continues to accumulate. As the artery narrows, blood pressure increases to maintain blood flow. Eventually, blood flow may be completely blocked, which would result in a heart attack or stroke depending on the site of the blockage. In vitro studies have demonstrated that the phenolic compounds prevent and even reverse the oxidation of LDL, and hence prevent and reduce the accumulation of oxidised LDL in arteries (Witzum and Steinberg 1991, Halliwell and Chirco 1993, Whitehead et al. 1995, Abbey and Kerry 1996).

The phenolic compounds are located in the skins and seeds of grapes and during fermentation they are extracted into the juice. The concentration of phenolic compounds in wine is significantly greater than that in the majority of these foodstuffs, and their concentration is six-fold greater in red than that in white wine. This difference also correlates with the difference in antioxidant capacity between red and white wine, and reflects the colour or pigment difference between red and white grapes, and hence wine. In addition, there are differences in the concentration of phenolic compounds between the varieties of red and white grapes, and viticultural and winemaking factors also influence and contribute to the concentration of phenolic compounds in the final or finished wine.

The next query to be considered in order to answer the question as to whether wine is just another alcoholic beverage, is whether the wine-derived phenolic compounds are actually absorbed across the small intestine into the blood stream. Approximately 90% of the alcohol component is readily absorbed. The in vivo studies undertaken to date have not conclusively established whether the phenolic compounds are absorbed. Of these seven studies, four have demonstrated that they are and in sufficient amount to be active antioxidants absorbed (Maxwell et al. 1994, Whitehead et al. 1995, Fuhrman et al. 1995, Nigdikar et al. 1998, Leighton et al. 1999), one has shown no significant absorption but has shown activity (Sharpe et al. 1995), and one has failed to show any absorption and activity. This variance may reflect variance in study design and analytical methods, such that significant antioxidant activity may only be observed following the medium- to long-term consumption of wine, although a paper in press by Croft et al. shows significant absorption of particular phenolic compounds after the acute or short-term consumption of wine. Furthermore, an additional role for the phenolic compounds has also been demonstrated in platelet aggregation, complementary to that of the alcohol component of wine (Pendurthi et al. 1999). Another way to answer the question as to whether wine is just another alcoholic beverage, is to consider the characteristics of the consumers of wine, spirits and beer. Risk factors for cardiovascular disease include a high body mass index (weight), a diet high in fats and low in fruits, grains and vegetables, a lack of exercise, cigarette smoking, an unbalanced plasma cholesterol concentration (ratio of HDL to LDL), and a high blood pressure (Hunter et al. 1995, Norrish et al. 1995, Wieslisbach et al. 1997). Interestingly, consumers of wine generally are observed to have a healthier diet, exercise more, smoke less and have a lower level of other risk factors for cardiovascular disease (Klastsky et al. 1990, Klatsky and Armstrong 1993). Additionally, wine is also associated with a different pattern of consumption to that of spirits and beer. For example, only wine is generally consumed as an integral component of a meal (Klatsky et al. 1990), which attenuates the blood alcohol concentration achieved. Populations that regularly consume a moderate amount of alcohol with a meal, such as those of the Mediterranean countries, and of central and southern France, have a significantly lower risk of cardiovascular disease (St Leger et al. 1979, Renaud and de Loergeril 1992).

Thus, while I could not conclude in my musings of 1996 and in 1998 that there was a difference between the alcoholic beverages re a cardio-protective effect, I can conclude with certainty that there is a difference, but the significance of this difference is what has to be determined now. .

This topic was first presented by C. Stockley at The Wolf Blass Foundation Wine and Health Conference in Sydney in 1996 and in the Journal of Wine Research 1997, Vol 8, No 1.

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