Some interesting and useful background information before we start:
There is no clear consensus among countries on what constitutes one “standard drink” of alcohol.
For example, here is a sample of the number of grams of alcohol considered to be 1 standard alcoholic drink in countries around the world (1,2).
8 grams in the UK
10 grams in Australia, France, Germany, Ireland, China, Hong Kong, Vietnam and the WHO
12 grams in Italy, Denmark, Finland and Switzerland
13.6 grams in Canada
14 grams in the US, Portugal and Chile
17 grams in Hungary
19.75 grams in Japan
20 grams in Austria
In addition, most people enjoying a drink are not clear on the number of standard drinks contained in a particular bottle of alcohol of any kind. It is likely then that the casual measurement of a “standard drink” is not very accurate and may lead to people underestimating their personal alcohol consumption.
For years it has been thought that small amounts of alcohol enjoyed now and then were healthy. The moderate consumption of alcohol (defined in Canada and the US as 2 drinks (28 grams alcohol) or less in a day for men or 1 drink (14 grams alcohol) or less in a day for women, on days that alcohol is consumed) looked to be protective for cardiovascular disease. This idea has been represented as a U- or J-shaped curve on a graph, with both teetotalers at one end and heavy drinkers at the other end having a higher risk of death from cardiovascular disease while light to moderate drinkers land in the middle with the lowest risk. (3) However, over the last decade or so new information has emerged that casts doubt on this idea.
New Data For the Effect of Alcohol Consumption on Cardiovascular Disease
A meta-analysis from 2008 showed that any alcohol consumption at all was associated with an increase in the risk of hypertension in men. The rise in blood pressure increased as the amount of alcohol consumed rose and occurred even with the consumption of only 1 or 2 standard drinks per day. (4)
A meta-analysis from 2018 suggested that the dangers from alcohol begin much sooner than previously thought. Data from three large cohorts in high-income countries that included nearly 600,000 current drinkers found that the risk of all-cause mortality began to increase at a level of approximately 100 gm of alcohol per week (about 7 standard drinks). This data illustrated a linear association between rising alcohol consumption and increased risk for stroke, coronary artery disease, heart failure, fatal hypertensive disease and aortic aneurysms. Deeper analysis suggested that drinkers of beer or spirits and binge drinkers had the highest risk for all-cause mortality. Researchers concluded that limits for alcohol consumption should be lower than those presently recommended in guidelines. (5)
In a randomized study from May 2021, the data from over 300,000 participants from the U.K. Biobank database revealed that any amounts of alcohol intake increase cardiovascular risk.
Compared to abstainers, those consuming …
…1 drink daily had 1.2 times higher risk of both hypertension and coronary artery disease (CAD)
…2 drinks daily had 1.7 times higher risk of hypertension and 2.3 times higher risk of CAD
…3 drinks daily had 3.4 times higher risk for hypertension and 6.2 times higher risk of CAD
…4 drinks daily had 8.9 times higher risk for hypertension and 25.9 times higher risk of CAD
Risks for other cardiovascular disorders such as stroke, heart failure and atrial fibrillation were also significantly increased with alcohol intake. (6)
Perhaps the most innovative evidence indicating that moderate drinking does not provide protection from cardiovascular conditions such as stroke came from a study completed in China in 2019. Its investigators performed not only traditional epidemiologic analysis but also genetic epidemiologic analysis on more than 500,000 participants who were followed for about ten years. Consistent with previous studies, the traditional analysis in men showed U-shaped associations between self-reported alcohol intake, stroke, and myocardial infarction, suggesting that moderate alcohol use was associated with the lowest risk for these conditions. Adding the genetic component, however, revealed more precise information. Both analyses indicated that the average alcohol intake in current drinkers was about 280 grams of alcohol per week and this was linked to an increase in systolic blood pressure of about 5 mm Hg. But the genetic analysis also revealed that men drinking an average of 280 grams of alcohol per week displayed a 27% excess risk of ischemic stroke, a 58% excess risk of intracerebral hemorrhage and a 38% excess risk of total stroke. These excess stroke risks are about twice as great as expected just from the effects of alcohol on systolic blood pressure. This discrepancy was theorized to be due to adverse effects of alcohol on factors other than blood pressure and to the fact that blood pressure differences due to genetic factors are present throughout the whole of adult life. When the results were subjected to a technique called Mendelian randomization, they showed that the apparently protective effects of moderate alcohol consumption were not caused by alcohol itself but were artifacts of reverse causation and confounding. (7)
NOTE: Reverse causation is what happens when lifestyle habits are changed in an effort to avoid consequences. For example, many alcoholics become nondrinkers after being diagnosed with cirrhosis of the liver. They switch to healthier habits, but their risk for disease or death remains high. These participants in a study will increase the amount of apparent harm from alcohol in the nondrinking group.
Confounding is a “blurring” of effects that occurs when an investigator tries to determine the effect of a factor on the occurrence of a disease but ends up measuring the effect of a different factor altogether. Among people with low average alcohol consumption, infrequent drinkers tend to drink relatively high amounts on the days they do drink and therefore have worse risk factor profiles compared to more frequent drinkers. This can skew results to suggest favourable associations for “moderate” average alcohol consumption.
The final results of this study show that, among all men in the study, alcohol was responsible for approximately 8% of the ischemic strokes that occurred and 16% of the intracerebral hemorrhages (a sub-type of stroke). Blood pressure and stroke risk rose steadily as alcohol intake increased. Even moderate alcohol consumption increased the risk of stroke. Findings for heart attack were less clear but further research is continuing. (7)
New Data For the Effect of Alcohol Consumption on Cancer
It’s not just cardiovascular disease that is affected by alcohol use. Research notes that the consumption of alcoholic beverages is causally linked to cancers of the oral cavity, pharynx, larynx, esophagus, colon, rectum, liver, and female breast. Evidence is also accumulating that alcohol consumption is associated with increased risks of melanoma and of prostate and pancreatic cancers. (8)
In August of 2021, a systematic literature review examined cases of cancer that were attributed to alcohol consumption. It calculated the contribution of moderate drinking (<20 grams alcohol per day), risky drinking (20–60 grams alcohol per day), and heavy drinking (>60 grams alcohol per day) to the total burden of alcohol on cancer, as well as the contribution of each 50-gram increment increase in alcohol consumption up to a maximum of 150 grams per day. (9)
Results revealed that 4.1% of all new cases of cancer globally in 2020 were attributable to alcohol consumption. The highest frequencies of alcohol-attributable cancers were found in males drinking from 30 grams to less than 50 grams per day and in females drinking from 10 grams to less than 30 grams per day. Lead author of this study, Harriet Rumgay, from the International Agency for Research on Cancer in Lyon, France, stated the following, “Drinking less means you’ll have a lower risk of cancer than if you drink heavily, but there is no safe limit of alcohol consumption.” She also pointed out that consuming one to two alcoholic drinks per day contributed to more cancer cases among women than among men. (9)
Earlier in 2021, another investigation estimated that alcohol contributed to 4.8% of cancer cases and 3.2% of cancer deaths in the United States. (10)
Extensive epidemiologic data have linked an alcohol consumption of 15 to 30 grams per day with a 30 to 50% increase in risk of breast cancer. (11)
New Data For the Effect of Alcohol Consumption on the Brain
In an investigation from May 2021 the effects of alcohol use on the brain were studied. Over 25,000 participants between the ages of 47 and 62 underwent brain scans and cognitive testing. Results indicated that as alcohol consumption increased, brain grey matter volume decreased and widespread adverse effects on brain function were observed. Binging on alcohol resulted in additional negative effects on the brain. These consequences were found for all types of alcohol including wine, beer and spirits. The investigators concluded that there is no safe dose of alcohol for the brain. (12)
This new science has prompted many health organizations to revise their recommendations for alcohol consumption. The World Health Organization (WHO) considers alcohol a toxic substance whose use is accountable for 7.1% of the global burden of disease for males and 2.2% for females. In addition, the WHO now states that alcohol is the leading risk factor for premature illness and disability among those between 15 and 49 years of age and accounts for 10% of all deaths in this age group (13). The American Heart Association recommends that those who do not already consume alcoholic beverages should not start doing so because of the negative long-term effects of alcohol consumption. They point out that even light alcohol use (up to 1 drink daily) increases the risk of cancer. (14) The Canadian Cancer Society advises us to limit alcohol and they state that “drinking any type or amount of alcohol increases your risk of developing cancer. The less alcohol you drink, the more you reduce your risk.” (15) Since 2012, the American Cancer Society has suggested that alcoholic intake not exceed more than 1 drink per day for women or 2 drinks per day for men. However, on June 9, 2020 they strengthened their guidelines to say that “it is best not to drink alcohol”. (16)
Canadian physicians have also begun to raise their voices about the dangers of alcohol. They are seeing patients harmed by drinking habits who have no knowledge about the potential perils of this drink. Though any health benefits from alcohol have now been largely refuted, the idea that small amounts are healthy continues to circulate and many physicians feel that it is imperative that every person becomes aware of the real dangers of alcohol. To that end, they are advocating that warning labels be added to bottles of alcohol and are looking to the Canadian Medical Association to promote explicit warning labels on alcohol bottles that define the link of alcohol consumption with cancer. Health Canada recently stated that it is in the process of researching the best way to inform Canadians of the dangers of alcohol and that new national low-risk drinking guidelines are coming. Several European countries are also considering warning labels on alcohol. (17)
Most recently, on January 20, 2022, the World Heart Federation (WHF) stated that the evidence is very clear that the data does not support the widely held belief that consuming small to moderate amounts of alcohol is good for cardiovascular health. Their new Policy Brief goes on to say that even small amounts of alcohol have been shown to raise the risk for cardiovascular disease, including coronary disease, stroke, heart failure, hypertensive heart disease, cardiomyopathy, atrial fibrillation, and aneurysm. They state that alcohol use is also a major avoidable risk factor for cancer, digestive diseases, infectious diseases and injuries, both intentional and unintentional, and that, given the current evidence, no level of alcohol is safe.(18)
Why wait for the government to tell us what to do? The proof is already right before our eyes. The results of many well-designed studies have revealed the risks of alcohol consumption. It is up to each one of us to decide how much of this toxic substance we are going to allow into our bodies.
3 de Gaetano, G., Costanzo, S. Alcohol and Health: Praise of the J Curves. J Am Coll Cadriol. 2017 Aug; 70(8): 923-925.
4 Roerecke, M., Tobe, S.W., Kaczorowski, J., et al. Sex-specific associations between alcohol consumption and incidence of hypertension: a systematic review and meta-analysis of cohort studies. J Am Heart Assoc 2018 June 27; 7(13): e008202-e008202. Doi: 10.1161/JAHA.117.008202.
5 Wood, A.M., Kaptoge, S., Butterworth, A.S., Willeit, P., Warnakula, S., Bolton, T., et al. Risk thresholds for alcohol consumption: combined analysis of individual-participant data for 599 912 current drinkers in 83 prospective studies. Lancet. 2018 Apr 14; 391(10129):1513-1523. Doi:10.1016/S0140-736(18)30134-X.
6 Biddinger, K.J., Emdin, C., Haas, M.R., Wang, M., et al. Alcohol Increases Risk Of Cardiovascular Disease At All Levels Of Intake. Circulation May 18 2021; 143(Suppl 1): A056. Doi.org/10.1161/circ.143.suppl_1.056.
7 Millwood, I.Y., Walters, R.G., Mei, X.W., Guo, Y., Yang, L., Bian, Z. et al. Conventional and genetic evidence on alcohol and vascular disease aetiology: a prospective study of 500 000 men and women in China. Lancet. May 4, 2019; 393(10183): 1831-1842. Doi:https://doi.org/10.1016/S0140-6736(18)31772-0.
9 Rumgay, H., Shield, K., Charvat, H., Ferrari, P., Sornpaisarn, B., Obot, I., et al. Global burden of cancer in 2020 attributable to alcohol consumption: a population-based study. Lancet Oncology. August, 2021; 22(8): P1071-1080. Doi:https://doi.org/10.1016/S1470-2045(21)00279-5.
10 Sauer, A.G., Fedewa, S.A., Bandia, P. et al. Proportion of cancer cases and deaths attributable to alcohol consumption by US state, 2013-2016. Cancer Epidemiology. April 2021; 71(Part A). Doi.org/10.1016/j.canep.2021.101893.
11 McDonald, J.A., Goyal, A., Terry, M.B. Alcohol Intake and Breast Cancer Risk: Weighing the Overall Evidence. Curr Breast Cancer Rep. 2013; 5(3): 10.1007/s12609-013-0114-z. Doi:10.1007/s12609-013-0114-z.
12 Topiwala, A., Ebmeier, K.P., Maullin-Sapey, T., Nichols, T.E. No safe level of alcohol consumption for brain health: observational cohort study of 25,378 UK Biobank participants. medRxiv 2021.05.10.21256931. Doi: https://doi.org/10.1101/2021.05.10.21256931.
14 Mechanick, J.I., Kushner, R.F. Lifestyle Medicine: A Manual for Clinical Practice. Springer Science. April 21, 2016. Page 153. ISBN 978-3-319-24687-1.
16 Rock, C.L., Thomson, C., Gansler, T., Gapstur, S.M.,et al. American Cancer Society guideline for diet and physical activity for cancer prevention. CA A Cancer J Clin. 2020; 70: 245-271. Doi.org/10.3322/caac.21591.