There is no shortage of news stories promoting the benefits of alcohol consumption, such as a recent article claiming that “a glass of red wine is the equivalent of an hour at the gym” (Sitch, 2016). The health community for many years believed that moderate alcohol consumption provides some health benefits to certain types of people. But is this really true?

According to a 2016 study on the relationship between alcohol and all-cause mortality, low-levels of alcohol consumption may not have the same protective effect on health as what was once thought.

In their meta-analysis of 87 studies, Stockwell, Zhao, Panwar, Roemer, Naimi, & Chikritzhs (2016) suggest that the classic J-shaped curve, where low-volume drinkers experience lower-risk for all-cause mortality than people who abstain from alcohol, may be a product of poor quality methodologies in study design. Many of the studies on the association between alcohol and all-cause mortality included former and occasional drinkers in the abstainer categories. In the case of former drinkers, individuals in these categories are typically biased towards ill-health. People who age and/or become unwell are more likely to quit or substantially reduce their alcohol consumption. As a result, individuals in the abstainer category are more likely to have poor health from the outset. So when researchers compared the risk of death between these individuals and those who are classified as low-volume drinkers, low-volume drinkers appeared to have reduced risk (Stockwell et al., 2016).

When Stockwell and colleagues (2016) adjusted for abstainer bias and other study characteristics that could potentially influence the association between alcohol and all-cause mortality, they found that low-levels of alcohol consumption had no protective effect and the pattern of association between alcohol and mortality is more likely to be linear than J-shaped. Put more simply, the more alcohol an individual consumes, the higher their risk for all-cause mortality.

While some researchers question the methodology of Stockwell et al.’s study, it does provide some insight into why some studies have found protective effects of alcohol that are highly unlikely – like the association between low-levels of alcohol consumption and reduced risk for alcoholic liver cirrhosis (Rehm et al. 2010), and reduced risk for developmental disorders among infants born from low-volume drinking mothers (Kelly et al., 2009).

While low-levels of alcohol consumption may not reduce a person’s risk for all-cause mortality, what about the overall relationship between alcohol and health?  For the most part, alcohol has a negative impact on health and is a risk factor for various conditions (Butt, Beirness, Gliksman, Paradis, & Stockwell, 2011). For example, there is increasing evidence of the relationship between alcohol and cancer. With as little as one drink per day, an individual increases their risk of developing cancer of the breast, colon and rectum, esophagus, larynx, liver, mouth and pharynx (Canadian Centre on Substance Abuse [CCSA], 2014).

However, research does suggest that there are some health benefits of low-levels of alcohol consumption for some health conditions among distinct population groups– namely diabetes and some forms of heart disease for individuals over 45 years of age (CCSA, 2013). Unfortunately, these benefits are often misinterpreted to apply to all age groups and are often thought of in isolation from the increased risk for other health conditions, or all-cause mortality. Given that many people underestimate the amount of alcohol they consume, it is also likely that an individual’s perceived benefit is inaccurate (Public Health Agency of Canada, 2016).

Clearly there is a complex relationship between alcohol and health. It is no wonder the public is genuinely confused about the benefits and harms of moderate alcohol consumption.  The message isn’t always clear even among and between health professionals and there are a lot of important nuances that get missed when communicating the message. There is a need for more clear and consistent, evidence-based messaging to help people understand that even at moderate levels, the alcohol they consume can increase their risk for various health conditions and have a negative impact on their health.

 
References:
 
Butt, P., Beirness, D., Gliksman, L., Paradis, C., & Stockwell, T. (2011). Alcohol and health in Canada: A summary of evidence and guidelines for low risk drinking. Ottawa, ON: Canadian Centre on Substance Abuse.
 
Canadian Centre on Substance Abuse. (2013). Canada’s low-risk alcohol drinking guidelines: Frequently asked questions. Retrieved from: http://www.ccsa.ca/Resource%20Library/2012-FAQs-Canada-Low-Risk-Alcohol-Drinking-Guidelines-en.pdf
 
Canadian Centre on Substance Abuse. (2014). Cancer and alcohol. Retrieved from: http://www.ccsa.ca/Resource%20Library/CCSA-Cancer-and-Alcohol-Summary-2014-en.pdf
 
Kelly, Y., Sacker, A., Gray, R., Kelly, J., Wolke, D., & Quigley, M. A. (2009). Light drinking in pregnancy, a risk for behavioural problems and cognitive deficits at 3 years of age? International Journal of Epidemiology, 38, 129–140. doi:10.1093/ije/dyn230.
 
Public Health Agency of Canada. (2016). The chief public health officer’s report on the state of public health in Canada, 2015: alcohol consumption in Canada. Ottawa, ON: PHAC.
Rehm, J., Taylor, B., Mohapatra, S., Irving, H., Baliunas, D., Patra, J., & Roerecke, M. (2010). Alcohol as a risk factor for liver cirrhosis: A systematic review and meta-analysis. Drug and Alcohol Review, 29,437–445. doi:10.1111/j.1465-3362.2009.00153.x.
 
Sitch, D.M. (2016, January 8). A glass of red wine is the new equivalent to an hour at the gym says new study. Huffpost United Kingdom. Retrieved from http://www.huffingtonpost.co.uk/2016/01/08/a-glass-of-red-wine-is-the-equivalent-to-an-hour-at-the-gym-says-new-study_n_7317240.html
 
Stockwell, T., Zhao, J., Panwar, S. Roemer, A., Naimi, T., & Chikritzhs, T. (2016). Do “moderate” drinkers have reduced mortality risk? A systematic review and meta-analysis of alcohol consumption and all-cause mortality.  Journal of Studies on Alcohol and Drugs 77(2), 185–198. doi:10.15288/jsad.2016.77.185