Further evidence that low-to-moderate consumption of alcoholic beverages may be causally related to improved blood lipids

The present study provides important data supporting that light-to-moderate   consumption of alcoholic beverages has favorable effects on most blood lipid levels.

Health benefits of low-to-moderate consumption of alcoholic beverages are well documented. However, the mechanisms involved are not entirely clear. Several controlled studies have suggested that the protective effect might be mitigated through an improved blood lipid profile.

Thus, a group of US researchers used an innovative approach – the Mendelian RandomizationThe basic idea of the Mendelian randomization is to use genetic variables as instrumental variables ... (MR) (*) – to help determine the degree to which the effects on blood lipids of reported alcohol consumption may be confounded by associated lifestyle factors. The analyses from a large number of subjects in the US-based Atherosclerosis Risk in Communities (ARIC) study are based on repeated assessments of alcohol consumption and data on common and rare genetic variants in alcohol dehydrogenase and acetaldehyde dehydrogenase genes, which are known to affect the tendency of subjects to consume alcoholic beverages and perhaps modify its biologic effects. This approach should permit a better, unbiased assessment of alcohol as a “causative factor” for the improved lipid profiles generally found among moderate drinkers.

The results strongly support favorable effects of moderate drinking on most blood lipid values, specifically an increase in HDL-cholesterol and decreases for triglycerides and LDL-cholesterol.

Vu KN, Ballantyne CM, Hoogeveen RC, et al. Causal Role of Alcohol Consumption in an Improved Lipid Profile: The Atherosclerosis Risk in Communities (ARIC) Study. PLoS One. 2016 Feb 5;11(2):e0148765.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0148765

For more information about this article, read the scientific abstract here.

(*) Mendelian RandomizationThe basic idea of the Mendelian randomization is to use genetic variables as instrumental variables ... (MR):

The basic idea of the Mendelian randomization is to use genetic variables as instrumental variables, i.e., genes associated with an exposure (in this study, alcohol consumption or alcohol metabolism) but not directly related to outcome (in this study, HDL-cholesterol and other lipid parameters).  Since the genetic pattern is determined before birth, it should not (at least, in theory) be confounded by later lifestyle exposures or outcome variables.  Thus, it allows the investigators to make causal inference.

Mendelian randomization provides an approach to addressing questions of causality without many of the typical biases that impact the validity of traditional epidemiologic approaches. While Mendelian randomization studies can provide important suggestive evidence for causal relations between risk factor (consumption of alcoholic beverages in this case) and disease outcome (blood lipid levels), they are not true experiments and are dependent on several assumptions. Evidence from randomized controlled trials, when possible, should continue to guide clinical decisions.