Cutting alcohol consumption, even for light-to-moderate drinkers, could be linked to improved cardiovascular health, including a reduced risk of coronary heart disease, lower body mass index and blood pressure, according to research published this week.
The findings, published in the British Medical Journal, challenge the results of previous observational studies which found that the consumption of light-to-moderate amounts of alcohol may have a protective effect on cardiovascular health.
The team, made up of researchers from UCL, the London School of Hygiene & Tropical Medicine and the University of Pennsylvania, used a genetic approach to try and bypass inconsistencies of assessing the relationship between alcohol and health. For example, the fact that non-drinkers often include people who stopped drinking because of illness. Therefore, they appear to be at higher risk of coronary heart disease when compared to low to moderate drinkers.
BRC supported Professor Juan P. Casas of the UCL Institute of Cardiovascular Science and senior author on the paper said: “While the damaging effects of heavy alcohol consumption on the heart are well-established, for the last few decades we have often heard reports of the potential health benefits of light-to-moderate drinking. However, we now have evidence that some of these studies suffer from limitations that may affect the validity of their findings”.
Evidence from over 50 studies into the drinking habits and cardiovascular health of over 260,000 people was examined.
Researchers found that individuals who carry a genetic variant which tends to lower their alcohol consumption have, on average, a more favourable cardiovascular profile. The researchers say this suggests that a reduction in alcohol consumption, even for light-to-moderate drinkers, is beneficial for cardiovascular health.
Specifically, the researchers found that the individuals who carried the genetic variant that tends to lower alcohol consumption had on average a 10% lower risk of having coronary heart disease, lower blood pressure and a lower body mass index.
Professor Casas said: “We saw a link between a reduced consumption of alcohol and improved cardiovascular health, regardless of whether the individual was a light, moderate or heavy drinker. Assuming the association is causal, it appears that even if you’re a light drinker, reducing your alcohol consumption could be beneficial for your heart.”
Researchers used a gene that serves as an indicator of alcohol consumption. Individuals that carry a genetic variant of the ‘alcohol dehydrogenase 1B’ gene are known to breakdown alcohol at a different pace. This causes symptoms including nausea and facial flushing, and has been found to lead to lower levels of alcohol consumption in the long term. By using this genetic variant as an indicator of lower alcohol consumption, they were able to find associations between these individuals and improved cardiovascular health.
Studies into the long-term health effects of alcohol can be challenging, due to the difficulty of setting up randomised control trials involving many individuals who will maintain the same alcohol consumption levels over an extended period of time. The authors say that their study’s genetic approach parallels the principles of a randomised control trial and therefore makes it less prone to some of the limitations of previous observational studies.
The study was funded by the British Heart Foundation and the Medical Research Council.
Dr Shannon Amoils, Senior Research Advisor at the British Heart Foundation, said: “Studies into alcohol consumption are fraught with difficulty in part because they rely on people giving accurate accounts of their drinking habits.
“Here the researchers used a clever study design to get round this problem by including people who had a gene that predisposes them to drink less. The results reinforce the view that small to moderate amounts of alcohol may not be healthy for the heart although the study would need to be repeated in a larger group of people for definitive results.
Whilst the heart health effects of light to moderate alcohol consumption are still unclear, what is clear is that drinking more than the recommended limits of alcohol can have a harmful effect on the heart.”
To read Association between alcohol and cardiovascular disease: Mendelian randomisation analysis based on individual participant data in full click here.
