Wine and Cardiovascular Disease: A New Marker Confirms Risk Reduction

When it comes to alcohol consumption, the prevailing trend in recent years has been to assert that there is no safe level of consumption—that is, all drinkers, even light and moderate ones, are at higher risk of premature death compared to non-drinkers. As we have mentioned previously, this rather radical stance is based on a limited and somewhat biased interpretation of research from the past 50 years, and it fails to take into account the type of alcoholic beverage consumed as well as the broader context in which drinking typically occurs.

Regarding the type of beverage, increasing evidence suggests that moderate consumption of red wine is preferable to that of other types of alcohol (see our article on the subject). Although the cardiovascular benefits associated with wine are similar to those of other alcoholic beverages, the increased risk of certain cancers and alcohol-related mortality appears to be significantly lower for wine—even at relatively high amounts (300 g of alcohol or about 20 drinks per week) (Figure 1). In terms of health impact, it therefore seems inappropriate to consider only total alcohol intake without accounting for the type of alcoholic drinks consumed.

It has been suggested that the cardioprotective effect of wine could be, at least in part, attributable to the fact that moderate wine drinkers are generally at lower risk of cardiovascular disease due to other protective lifestyle factors (higher socioeconomic status, better diet, more physical activity). Although it is difficult to accurately measure the contribution of these factors, it is nonetheless possible that they amplify the positive effect of alcohol consumption on cardiovascular health. In other words, one should not only consider alcohol consumption in isolation, but also the broader context in which it occurs.

This concept is well illustrated by studies that have shown that moderate alcohol consumption (1 drink per day for women, 1–2 drinks per day for men) as part of an overall healthy lifestyle (no smoking, regular physical activity, plant-rich diet, normal body weight) is associated with a very significant (80%) reduction in the risk of myocardial infarctionand an increase of 12–14 years in life expectancy, including several additional years in good health.

These findings are clearly incompatible with the notion that any amount of alcohol is unsafe. This is also why low to moderate alcohol intake is still recommended today by highly reputable institutions such as the Harvard T.H. Chan School of Public Health and the U.S. National Institute on Alcohol Abuse and Alcoholism (NIAAA) to reduce cardiovascular disease risk.

The Mediterranean Diet

Another example of the importance of the type of alcohol and the context in which it is consumed is the Mediterranean-style diet. This exemplary diet has been recognized for many years for substantially reducing the risk of cardiovascular disease, both in the general population and in heart attack survivors. In addition to the positive effects provided by a high intake of plant-based foods and extra virgin olive oil, it has been proposed that moderate alcohol consumption—mainly in the form of wine consumed with meals—could contribute to the cardioprotective effects of this type of diet. However, the actual benefits provided by wine remain difficult to quantify precisely, as it is very challenging to measure the amounts consumed by participants in epidemiological studies. In most cases, these studies rely on self-reported information about wine consumption (via questionnaires), which can lead to measurement errors given the well-documented tendency of many individuals to underestimate their alcohol intake.

Tartaric Acid: An Objective Marker of Wine Consumption

Unlike most fruits, whose organic acid content is mainly in the form of malic acid and citric acid, grapes are notable for containing high amounts of tartaric acid (see Table 1). Since this organic acid is not metabolized during fermentation, it is also found in large quantities in wine, where it plays a very important role in the stability, appearance, and taste of the final product.

Table 1. Tartaric Acid Content of Common Fruits. From Storcksdieck (2006). * mg/100 mL and varies depending on the type of wine.

Studies show that urinary tartaric acid levels are closely correlated with the amount of wine consumed, and this measurement could therefore be used to objectively assess wine intake, helping to bypass the issues associated with self-reported data.
A recent study tested this new approach using data collected as part of the randomized PREDIMED trial—the largest clinical study to date on the cardioprotective effects of the Mediterranean diet. Researchers measured urinary tartaric acid levels in 1,232 participants from the trial and analyzed the incidence of cardiovascular disease according to five broad categories of tartaric acid excretion, corresponding to virtually no wine consumption, very light, moderate, or high wine intake (Figure 2).
Overall, the data analysis confirms the typical “J-shaped” cardioprotective effect of wine observed in most studies—that is, individuals who excrete tartaric acid levels corresponding to light to moderate wine consumption (1–8 glasses per week) have a lower risk of cardiovascular events than those who drink less (<1 glass per month) or those who consume larger quantities (>10 glasses per week).

In summary, the use of tartaric acid as an objective biomarker confirms the beneficial effects associated with light to moderate wine consumption on the risk of cardiovascular disease.