Moderate alcohol consumption can protect against coronary heart disease, but only for people who have a particular genotype, according to a new study.
The study included 618 Swedes with coronary heart disease and a control group of 3,000 healthy subjects. The subjects were assigned to various categories based on the amount of alcohol they consumed (ethanol intake).
They were tested in order to identify a particular genotype (CETP TaqIB) that previous studies had found to play a role in the health benefits of alcohol consumption.
The results confirm the findings of the earlier studies. Moderate consumption of alcohol helps protect people with the genotype against coronary heart disease.
"In other words, moderate drinking has a protective effect among only 15 per cent of the general population," said Professor Dag Thelle, Professor Emeritus at Sahlgrenska Academy, University of Gothenburg.
The researchers believe that the advice frequently given about the health benefits of moderate alcohol consumption is far too sweeping.
"Moderate drinking alone does not have a strong protective effect. Nor does this particular genotype. But the combination of the two appears to significantly reduce the risk of coronary heart disease," said Professor Lauren Lissner, who also participated in the study.
The genotype codes for the Cholesterylester transfer protein (CETP), which affects the 'good,' cardio-protective HDL cholesterol that helps remove excess lipids from the blood vessels. One hypothesis is that alcohol somehow affects the CETP in a way that benefits HDL cholesterol.
A second hypothesis is that alcohol contains healthy, protective antioxidants.
The researchers believe that one or both of the hypotheses may prove correct, but the mechanisms by which HDL cholesterol or antioxidants might act remain unknown.
The study was published in the journal Alcohol.
