Wine May Increase Heart Healthy Fats in the Blood

Moderate alcohol consumption has long been known to be protective against mortality from coronary heart disease, but the biological mechanism of this effect is unknown. A new analysis suggests that drinking wine may alter the composition of healthy fats in the blood, mimicking the beneficial effects of seafood consumption and conferring protection against heart disease.

The Lyon Diet Heart Study is a classic “secondary prevention” trial testing if dietary plant-derived omega-3 fatty acids (alpha-linolenic acid, ALA) reduce the risk of a second cardiovascular incident in patients who have already had a heart attack. Half of the participants were asked to get more plant-derived omega-3 fatty acids in their diet and the other half were told to follow the dietary recommendations of their regular doctors (likely to recommend a low-fat prudent diet). The diet high in omega-3 fatty acids was found to be strongly protective against heart disease complications.
In the human body, plant-derived omega-3s are converted to the type of fatty acids obtained from fish (eicosapentanoic acid, EPA, and docosahexanoic acid, DHA). High blood levels of EPA and DHA are known to be protective against heart disease and sudden cardiac death. A new analysis of the Lyon Diet Heart Study published in the American Heart Journal shows that wine consumption is linked with increased EPA and DHA levels, irrespective of any other dietary factor. This association may help explain the mechanism by which alcohol consumption benefits cardiovascular outcome.

In this study, the data from participants that consumed both high and low amounts of plant-derived fatty acids were reanalyzed based on levels of alcohol intake. The study was conducted on middle-aged males in Lyon, France, so by far the majority of alcohol consumed was in the form of wine. Increased wine drinking was associated with progressively higher levels of blood EPA and DHA. In the group that ate fewer plant fatty acids, there was a 50% increase in blood EPA between non-drinkers and moderate drinkers, and a 21% increase in DHA. The group that ate more plant fatty acids had a 37% increase in EPA and 10% for DHA.

Importantly, the researchers statistically corrected for any variation in dietary fat consumption (specifically seafood), so only differences in alcohol ingestion can explain the changes observed. While other studies have found a correlation between wine drinking and increased blood EPA and DHA, none had adequately controlled for dietary fish intake.

Since plant-derived ALA is a precursor to EPA and DHA, this result suggests that alcohol may be important in the conversion of ALA to EPA and DHA in the human body. However, because this is a cross-sectional study it is impossible to precisely determine causality or the mechanism of action.

Another limitation of the study is that it is impossible to resolve which component in wine may be contributing to the finding. Alcohol is known to increase healthy HDL cholesterol, and several studies show a correlation between alcohol intake and a reduced risk of heart disease. But since this study specifically assesses the effect of wine (as opposed to other spirits) on blood fatty acid levels, there may be additional mechanisms involved. For instance, it is possible that the polyphenols (antioxidants) in wine are what confer the benefit.

The beauty of this finding is that the improvement in fatty acid profile from wine consumption seems to be clinically relevant. Based on the current consensus, small dietary changes in fatty acid consumption have a large clinical effect, so a 38% to 50% increase in EPA levels among moderate wine drinkers is noteworthy. Similar levels of improvement in lipid profiles from studies of fish consumption have shown considerable benefit for cardiovascular outcome. Thus, the present finding may offer dietary intervention as a possible method of cardiovascular protection, particularly when combined with increased omega-3 consumption.

In the present study, the difference between participants in the low fatty acid group who did not drink and those in the high fatty acid group who drank the most was an 83% increase in blood EPA, a change associated with a 50% to 75% reduced risk of heart attack. Such a dramatic difference represents a useful alternative to fish consumption for those who may not have access to seafood for whatever reason.

Thus, increasing both dietary omega-3 fatty acids and wine consumption may be helpful to protect against cardiovascular events. Plant-derived omega-3 fatty acids are abundant in walnuts, soy, flax and canola oils, and one gram per day is the current recommendation for heart protection. “Moderate” alcohol intake is one glass per day for women and two for men.

Please remember to drink responsibly.