We’re used to the mantra “everything in moderation.” But I doubt many of us needed a better excuse to skip merrily down to the local bar than hearing that a small amount of booze every day is good for your heart. While it does seem that moderate alcohol consumption can help protect against heart disease, unfortunately for those juiceheads out there, a new study has found that this is only true for those with a particular genetic make-up. And to ruin your day even more- only 15% of the general population have this genotype.

“Moderate drinking alone does not have a strong protective effect,” said study author Professor Lauren Lissner. “Nor does this particular genotype. But the combination of the two appears to significantly reduce the risk of coronary heart disease.”

For the study, which has been published in Alcohol, scientists from the University of Gothenberg enrolled more than 600 Swedes with coronary heart disease and almost 3,000 healthy controls. Participants were asked to honestly answer various questions about their lifestyles, such as how much alcohol they typically consumed, and whether they smoked or exercised regularly.

Alongside gathering this information, blood samples were taken for analysis. The scientists were interested in a gene that codes for the cholesteryl ester transfer protein (CETP). This protein shuttles fatty molecules between cholesterol carrier molecules, ultimately facilitating the transport of cholesterol from blood vessels to the liver. A few years back, a study hinted that a variation in this gene could be mediating the cardio-protective effects of alcohol, but the study only involved men and the finding was never confirmed with further studies.

They found that moderate alcohol intake (2 drinks per day for men and 1 for women) was associated with protection against coronary heart disease, but only in lucky individuals with a variation of the CETP gene known as B2. For the other 85% of the population that possess the B1 variant, a drink or two a day doesn’t seem to bestow any cardiovascular health benefits.

While the mechanisms behind this apparent cardio-protective effect are unclear at this stage, the researchers speculate that alcohol could somehow be affecting CETP in such a way that it benefits the “good” cholesterol in our bodies, HDL.

It’s clear that more research into this field is warranted, but study author Professor Dag Thelle thinks that if they can crack the mechanisms behind this protective effect, then one day it may be possible to perform simple genetic tests to determine which group you belong to. “That would be useful to know when offering advice on healthy alcohol consumption,” he added.

[Via Alcohol, University of Gothenberg, Huffington Post and Science]