A summary paper on the effects of alcohol consumption on biologic mechanisms associated with coronary heart disease provides an excellent review of a large number of intervention studies in humans. Appropriate analyses were done and the results are presented in a very clear fashion, although there was little discussion of the separate, independent effects of alcohol and polyphenols on risk factors.
The trials the authors reviewed have demonstrated that the moderate intake of alcoholic beverages leads to increases in HDL-cholesterol (good cholesterol), apolipoprotein A1, and adiponectin and decreases in fibrinogen, all factors associated with a lower risk of heart disease. The findings described in this paper strengthen the case for a causal link between alcohol intake and a reduced risk of coronary heart disease, suggesting that the lower risk of heart disease observed among moderate drinkers is caused by the alcoholic beverage itself, and not by other associated lifestyle factors.
The reviewers independently selected studies that examined adults without known cardiovascular disease and that compared fasting levels of specific biological markers associated with coronary heart disease after alcohol use with those after a period of no alcohol use (controls). A total of 4,690 articles were screened for eligibility, the full texts of 124 studies reviewed, and 63 relevant articles selected. Of 63 eligible studies, 44 on 13 biomarkers were meta-analysed in fixed or random effects models. Quality was assessed by sensitivity analysis of studies grouped by design. Analyses were stratified by type of beverage (wine, beer, spirits).
The authors concluded that favourable changes in several cardiovascular biomarkers (higher levels of high density lipoprotein cholesterol and adiponectin and lower levels of fibrinogen) provide indirect pathophysiological support for a protective effect of moderate alcohol use on coronary heart disease.