Alcohol and Cardiovascular Disease: The Tippling Point

If you drink alcohol, do so in moderation. If you don’t drink, don’t start.

So says the current advice of the American Heart Association in relation to alcohol and prevention of cardiovascular disease.

When it comes to the purported cardioprotective benefits of moderate alcohol consumption, the scientific world is divided into believers and skeptics and there are abundant data to support both points of view.

As reviewed in the 2014 World Cancer Report, issued by the World Health Organization’s (WHO’s) International Agency for Research on Cancer, concluded that no amount of alcohol is safe, at least when it comes to cancer risk.

This prompted a critique of the WHO report by the members of the International Scientific Forum on Alcohol Research in which they disputed the “paternalistic blanket condemnations against alcohol,” noting that “WHO seems to deliberately ignore the overwhelming scientific evidence showing that light-to-moderate consumption of alcohol not only reduces overall mortality but is usually not associated with an increased risk of cancer.”

Plausible but Not Proven

Is moderate drinking truly cardioprotective or is it merely a marker of a healthy lifestyle? Will we ever know for certain in the absence of randomized clinical trial data that will never be forthcoming, given the ethical and practical challenges entailed? For the nonbelievers, the evidence will always be on shaky ground, and adjustments for confounding will never fully cement the cracks.

Among the plausible explanations for alcohol’s cardiovascular effects include reductions in platelet aggregation and thrombotic markers such as fibrinogen, increases in HDL cholesterol (by about 8%),[1] and anti-inflammatory effects such as lowering C-reactive protein levels.[2] But epidemiologists have been led down the observational garden path before, notably with hormone therapy[3] and vitamin E,[4] 2 therapies widely purported to have cardiovascular benefits that did not hold up in randomized trials.[5,6] Documented effects on surrogate markers like HDL-C are also no guarantee of a reduction in hard events as seen in trials with niacin.[7,8]

The “goldilocks” amount of alcohol is said to be 1 to 2 drinks daily. However, amounts in or near this level have been associated with an increased risk for hypertension,[9] an effect the pro-alcohol lobby say is explained by heavier drinkers who underreport their intake.[10] This uncertainty about the true drinking status of study populations is at the crux of the debate on alcohol and cardiovascular health.

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