Over 75 experimental studies have examined the effects of alcohol intake on lipids, haemostatic factors, vitamins, glucose, insulin and lipid peroxidation. However only a few epidemiological studies have simultaneously examined the relation between alcohol intake, biochemical variables and subsequent risk of coronary heart disease (CHD).

From these studies it is estimated that half of the beneficial effects of moderate alcohol intake is due to increased high density lipoprotein cholesterol concentrations. This calculation may, however, be an underestimate because it does not take into account measurement error in the assessment of average alcohol intake or biological variability in HDL-lipoprotein cholesterol concentrations. Also potential confounding by other lifestyle factors such as diet, obesity and physical activity were usually not considered. Furthermore other biochemical variables such as fibrinogen, tryglycerides and insulin were not measured in these simultaneous models claim Rimm et al.

The study by Eric Rimm et Al, published in the BMJ (Volume 319,11th Dec 99) sought to clarify the perceived short comings of the above studies by reviewing 42 experimental studies of alcohol, which provided 67 separate data records.

Rimm et al's study found that an experimental dose of 30g of ethanol a day increased concentrations of high density lipoproteins (HDL) by 3.99mg/dl, apolipoprotein A1 by 8.82mg/dl and triglyceride by 5.69mg/dl.

On the basis of published associations between these biomarkers and the risk of coronary heart disease 30g of ethanol a day would cause an estimated reduction of 24.7% in risk of coronary heart disease. The authors conclude;

'Results from our quantitative review suggest that moderate intake is causally related to lower risk of coronary heart disease through alcohol induced changes in lipids and haemostatic factors'.