Alcohol's Effects On Heart
Wine May Not Be Good For You, After All...
Since 1979, when the British journal The Lancet published the first article that claiming moderate drinking had a protective effect on the heart, the conventional wisdom, encouraged by many from the medical establishment, was that a pint of beer or two glasses of wine a day are good for the heart. A recent re-examination of the evidence for the heart protective effects of alcohol led to a surprising, totally opposite conclusion!
Is Alcohol Good For Your Heart?
"Do not assume there is a window in which the health benefits of alcohol are greater than the harms - there is probably no free lunch
." This is the conclusion of Dr Rod Jackson and his colleagues from the University of Auckland in New Zeeland, who published an article in the British Journal The Lancet
. The article, entitled "Light to moderate alcohol consumption not beneficial to health
", challenges the current evidence on which the alcohol's heart protective effects is based, calling it flawed. "Any coronary protection from light to moderate drinking will be very small and unlikely to outweigh the harms", they stated.
What About Prior Studies Showing Moderate Drinking Is Good?
As I wrote earlier, the first "scientific" confirmation of alcohol's protective cardiovascular effects was published in the 1970s and 1980s. None of those studies were randomized. For those accustomed with biomedical research, this should have been a red flag from the very beginning. The gold-standard in this field are the randomized, double-blind studies. Anything short of that is significantly less powerful in terms of identifying what causes what.
A randomized study is a research study in which patients are randomly assigned to a control group (receiving the standard treatment) or an intervention group (receiving the experimental treatment). Randomized, controlled trials are considered the most reliable and impartial method of determining the most effective medical treatment.
You may wonder how the moderate drinking message made it and received so much support and attention with for over 25 years now, with such a weak scientific basis?
A so called meta-analysis came to the rescue a few years after the first reports. Again for those who are not familiar with the statistical jargon, allow me to explain what a meta-analysis
is. It is essentially a method of summarizing previous research by reviewing and combining results from multiple CLINICAL TRIALS
. Meta-analyses are attempted when previous studies were too small individually to achieve meaningful or statistically significant results. Because combining data from disparate groups is problematic, meta-analyses usually are considered more suggestive than definitive
. You should remember this as we move along.
Based on this meta-analysis, light drinking was estimated to reduce the risk of heart disease by 20-25 percent. This is a huge number when we talk about chronic disease risk reduction. But remember that it is based on a pooling together of several studies too small to be individually conclusive, in a manner that is at best suggestive, as you will read further down...
Where Did Prior Studies Go Wrong?
First of all, as I said earlier, none of those studies was randomized. Therefore, confounding errors were not eliminated. For example, as Dr Jackson points out, people who stopped drinking because of heart problems may have been misclassified as "never drinkers" in those studies.
You may say to yourself: this is an exaggeratedly skeptical approach. After all, those studies might be up to something... Well, in 2005 a study of 200,000 American adults found that 27 of 30 cardiovascular risk factors were significantly more common in non-drinkers than light to moderate drinkers. Such risk factors, already present in study participants, could easily sway the results. In other words, the lower prevalence of heart disease in light to moderate drinkers is more likely to be the result of other factors than alcohol consumption.
What Is the Take Home Message?
I think there are a couple of important lessons here.
- First of all, we should take everything with a grain of salt. I'm not suggesting we should doubt or disregard scientific studies. But I want to suggest to you that whenever you come across a study that seems to contradict common sense principles of health, you should exercise caution before embracing it's conclusions. More often than not, further, better studies will shed more light on the topic and you will find your common sense was right, after all. You don't want to drink alcohol for 25 years and then find out it was useless. By then, you may be an alcoholic...
- Second, remember the human body, no matter how complex, is a unity. It is very unlikely a substance is so damaging to so many organs and systems, yet it benefits the heart. Again, common sense helps...
If you used to drink alcohol to protect your heart, it may be time to think again. You may want to start working on reducing other risk factors, like smoking, high fat and cholesterol diets, high blood pressure, etc.
When it comes to alcohol, as Dr Jackson says, there is no free lunch. The best thing is to stay away from it.