Drinking a small or moderate amount of wine may lower the risk of serious cardiovascular disease in people at a higher risk who are following a Mediterranean diet, according to research published in the European Heart Journal.

Previous studies on the effects of wine on cardiovascular health have produced inconsistent results. This may be in part because research often relies on people reporting how much wine they drink. Instead, in the new study, researchers measured the amount of a chemical, called tartaric acid, in participants' urine. Researchers say this is an "objective and reliable measure" of wine consumption.

The research was led by Professor Ramon Estruch from the University of Barcelona and the Hospital Clinic in Barcelona, Spain.

The new research is part of a larger Spanish study investigating the effect of a Mediterranean diet (high in olive oil, vegetables, fruit, nuts and fish, and low in sweet or processed food and drink) on people with a higher risk of developing cardiovascular disease.

All the people taking part had no cardiovascular disease at the start of the study, but they either had type 2 diabetes, or they had a combination of cardiovascular disease risk factors such as smoking, high blood pressure, high cholesterol, being overweight and/or a family history of cardiovascular disease.

As well as completing questionnaires about what they ate and drank, participants gave urine samples at the beginning of the study and after a year of following a Mediterranean diet. Tartaric acid is a chemical naturally found in grapes and grape-derived products such as wine. Tartaric acid is excreted in urine, meaning it can be measured to show if someone has consumed wine and/or grapes in the last five to six days.

To investigate the effect of drinking wine, researchers included a total of 1,232 participants. Participants were followed up for four to five years and during that time, there were 685 cases of cardiovascular disease (heart attack, coronary revascularisation, stroke or death from cardiovascular disease) during the study.

In this group of people at high risk of cardiovascular disease who were following a Mediterranean diet, researchers found that the risk of developing a cardiovascular event was reduced by 50% in light-to-moderate wine drinkers, defined as consuming half to one glass of wine per day, compared to those drinking very little or no wine.

Light drinking (between one glass per week and less than half a glass per day) reduced cardiovascular risk by 38%. However, this protective effect disappears in people who drank more than one glass per day.

The researchers took account of other factors that are known to influence the risk of cardiovascular disease, but they acknowledge that the design of the study means it can only show a link between drinking wine and cardiovascular events, and other factors cannot be ruled out.

Professor Estruch said, "By measuring tartaric acid in the urine, alongside food and drink questionnaires, we have been able to make a more accurate measurement of wine consumption. We have found a much greater protective effect of wine than that observed in other studies. A reduction in risk of 50% is much higher than can be achieved with some drugs, such as statins.

"This study examines the importance of moderate wine consumption within a healthy dietary pattern, such as the Mediterranean diet. Until now, we believed that 20% of the effects of the Mediterranean diet could be attributed to moderate wine consumption; however, in light of these results, the effect may be even greater.

"The participants in our study were older people at high risk of cardiovascular disease living in a Mediterranean country, so the results may not apply to other populations. Another key question is at what age moderate wine consumption could be considered 'acceptable'.

"Recent studies indicate that the protective effects of wine consumption are observed starting from the age of 35 to 40. It is also important to note that moderate consumption for women should always be half that of men, and it should be consumed with meals."

In an accompanying editorial, Professor Giovanni de Gaetano from IRCCS NEUROMED, Pozzilli, Italy and colleagues said, "The relationship between alcohol consumption, particularly wine, and cardiovascular disease (CVD) risk remains a topic of ongoing debate despite decades of related research.

"Numerous studies have suggested that moderate wine consumption, often defined as one glass per day, preferably during meals, is associated with a reduced risk of total mortality and CVD. However, this apparent protective effect is clouded by persistent uncertainties.

"The paper by Inés Domínguez-López et al, published in this issue of the European Heart Journal, sheds new light on this complex relationship by introducing an objective biomarker—urinary tartaric acid—as a measure of wine consumption and provides compelling evidence for its association with lower CVD risk.

"However, Domínguez-López et al also highlight the complexity of studying the effects of alcohol on health. While biomarkers such as urinary tartaric acid provide a more objective measure of exposure to wine, they do not capture the broader context of alcohol consumption, such as drinking patterns, lifestyle factors, and possible interactions with other dietary components.

"This limitation underscores the need for more refined research that captures the complexity of dietary patterns and their impact on health.

"The study by Domínguez-López et al represents an important step forward in our understanding of the complex relationship between wine consumption and cardiovascular health. By leveraging urinary tartaric acid as an objective biomarker, the authors provide robust evidence that moderate wine consumption is associated with lower CVD risk in a Mediterranean population at high cardiovascular risk.

"This work not only highlights the value of objective biomarkers in nutritional epidemiology but also supports the notion that light-to-moderate wine consumption may be part of a heart-healthy diet. However, the findings also remind us of the risks associated with higher levels of consumption, underscoring the importance of moderation.

"Future research should continue to explore the potential of biomarkers in unravelling the intricate links between dietary habits, lifestyle, and health outcomes."