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Alcohol, Omega-3 Fats, and Heart Health

The heart benefits of the traditional Mediterranean diet high in fish, fresh produce and red wine, have been well documented. A new study, part of the European IMMIDIET project, has shed new light on one of red wine's positive cardiovascular benefits.

The aim of the IMMIDIET project, funded by the European Union's initiative on food nutrition and health, is to examine the role of genetic and lifestyle factors in CVD prevention in Italians living at home, as wells as Italian immigrants to other countries.

High dietary and plasma concentrations of the marine fatty acids EPA and DHA are known to be protective against coronary heart disease (CHD) and sudden cardiac death. Alcohol, too, lowers the risk of ischemic stroke and CHD via a number of proposed pathways: increasing HDL, decreasing platelet aggregation and coagulation factors and exerting beneficial effects on endothelial function and inflammation.

Evidence also suggests that alcohol influences fatty acid metabolism. Low alcohol intake appears to increase long-chain fatty acid concentrations, while high alcohol decreases their concentration. Alcohol-induced increases in marine fatty acids might be a unique cardio-protective mechanism of alcohol.

In IMMIDIET, the researchers examined whether the heart benefits of alcohol extend to healthy men and women as well as male patients with cardiovascular disease as was shown in a previous study, the Lyon Diet Heart Study. They also examined whether various alcoholic beverages might affect marine lipid concentrations differently.

Study Design and Methods

In the framework of IMMIDIET, 1,604 men and women aged 26-65 years were enrolled in Italy, Belgium and England. A food frequency questionnaire was used to evaluate dietary and beverage intake. Blood samples were obtained, and plasma and red blood cell omega-3 fatty acids were assessed by gas chromatography.

Results

In fully adjusted multivariate analyses, alcohol intake In fully adjusted multivariate analyses, alcohol intake was positively associated with plasma EPA, DHA and EPA + DHA concentrations (p < 0.0001, p < 0.036 and p < 0.002 respectively) in women. EPA and EPA + DHA index in red blood cells were also positively associated with alcohol intake in females (p < 0.0001 and p < 0.037 respectively). In men, only plasma and red blood cell EPA concentrations were linked with intake of alcohol (p < 0.003 and p < 0.004 respectively).

In wine drinkers, stratified analyses revealed a statistically significant positive association between alcohol intake and both plasma and red cell EPA, DHA and the EPA + DHA index. In contrast, no association was found in those who drink beer and spirits.

Comments

This study examined three different populations with different dietary habits who consumed different types of alcoholic beverages. Analyses carried out on different beverages showed that the link between alcohol and omega-3 fatty acids was present in both wine drinkers and beer or spirits drinkers. However, adjusting for alcohol content of alcoholic beverages abolished the association with omega-3s in beer or spirits drinkers, while the associations with EPA and DHA were maintained or strengthened in wine drinkers.

These findings suggest that components in wine other than alcohol may be responsible for the higher omega-3 concentrations observed. The study authors propose that the polyphenol antioxidant components of wine may stimulate the synthesis of EPA and DHA from the precursor alpha-linolenic acid. Polyphenols may also be involved in that process by preventing alcohol-induced oxidation of long chain fatty acids, thus delaying their breakdown.

Reference
de Giuseppe R, et al. Alcohol consumption and n-3 polyunsaturated fatty acids in healthy men and women from 3 European populations. Am J Clin Nutr 89:354-62, 2009.