The effect of alcohol consumption on medical strokes

The effect of wine on our medical condition is not all bad, in spite of what you may hear these days. Consider this recent publication in the medical literature about its effect on the incidence of strokes, what is technically called Ischemic Stroke, which happens when a blood clot blocks a blood vessel in your brain (a medical emergency that can be fatal):

Alcohol use and types and ischemic stroke: a systematic review and meta-analysis
by Ahmad A Toubasi and Thuraya N Al-Sayegh
European Neurology 2025 88: 140-150

Here are the technical details, for those of you who are interested:
Introduction: This systematic review and meta-analysis was conducted to investigate the association between alcohol use pattern and ischemic stroke risk.
Methods: We searched PubMed, Scopus, Web of Sciences, Embase, and CENTRAL till the 1st of June, 2024. Studies were included if they were articles that assessed the impact of alcohol drinking pattern on the risk of ischemic stroke. The random-effect model was utilized to combine the results. Data analysis was performed using Meta XL, version 5.3.
Results: The total number of included participants was 21,293,471 from 125 studies. The model that investigated the association between light alcohol use and ischemic stroke risk showed no association (relative risk [RR] = 0.97, 95% confidence interval [CI]: 0.89-1.05). Moderate alcohol use was associated with significant decrease in ischemic stroke risk (RR = 0.87; 95% CI: 0.83-0.92), while heavy alcohol use was associated with significant increase in ischemic stroke risk (RR = 1.31; 95% CI: 1.19-1.44). Subgroup analysis among males showed results similar to the primary analysis, while among females only moderate alcohol drinking was significantly associated with ischemic stroke (RR = 0.50; 95% CI: 0.33-0.75). Moderate and heavy wine use was associated with significant reduction in ischemic stroke risk (RR = 0.61; 95% CI: 0.45-0.84; RR = 0.77; 95% CI: 0.63-0.93).
Conclusions: Our analysis provided a strong and robust evidence that there was a significant association between moderate and heavy alcohol use with ischemic stroke risk. However, this association varied by several variables including type of alcohol with the effect being more protective among people who use wine.

In this graph you can see see a summary of the outcome, in which people with light and moderate alcohol use (lines one and two) had far fewer strokes (ES) than those people with heavy alcohol use (line three). However, note that this was overall alcohol, while both moderate and heavy wine use was associated with a significant reduction in stroke.

Now, this is all very well, and as a wine drinker I like it. However, as a scientist I know that it is not actually a scientific experiment. A well-done alcohol study is a dietary intervention study, in which, for example, one group of participants abstains from alcohol completely, for the length of the experiment, while the other group will consume some specified amount of wine. This would produce much more convincing results. An introduction to this type of work is provided by Lewis Perdue at the Stealth Syndromes Human Study website (Consumer introduction to assessing scientific studies). Lewis also has other interesting relevant pages on this website (eg. A strength of evidence report card for human studies).

There are other pieces of work indicating that moderate wine consumption may benefit your cardiac health, such as: Is it true that … a glass of wine a day is good for your heart? Indeed, there is now an entire book about wine and health: Tony Edwards (2023) The Very Good News About Wine: Authoritative Health Evidence the Health Authorities Don’t Tell You, which covers topics like cancer, heart disease, diabetes, and dementia. This book was reviewed by Neal Hulkower (Uncorking the truth).

Nevertheless, perhaps I would not like to participate in an experiment in which I might increase my chances of getting a blood clot in my brain!