The genetics of alcohol dependency

I’m never drinking again – these are the words that you’ll hear from every hungover student, waking up after an intense circle and POP!. There’s usually as much truth in a student saying this as there is in your average Trump tweet, but what if genetics and evolution could be turning this alcohol abstinence into a reality? Two researchers from the University of Pennsylvania have reason to believe that may be the case.

Kelsey Elizabeth Johnson and Benjamin Voight did an analysis of data from the 1000 Genomes Project. This is a project that aimed to collect and sequence at least 1000 different human genomes (the project exceeded its target and got over 2,500 participants) of differing ethnicities, to obtain a detailed catalogue of genetic variation that exists within different human populations. Their paper analysed the evolutionary change that is currently being driven in humans by looking at variations emerging in different population groups. They looked for variants undergoing positive selection – when a gene variant rapidly increases in a population due to it conferring an advantage to the individual over other alleles. The authors found five genetic variants (hot spots) including changes to alcohol metabolism.

The authors found five genetic variants (hot spots) including changes to alcohol metabolism

Alcohol dehydrogenase (ADH) is an enzyme involved in breaking down ethanol into acetaldehyde, the first step in alcohol metabolism. The researchers’ analysis revealed an ADH variant which protects against alcoholism in five different populations, and people with this variant had a reduced alcohol dependency. Individuals with this variant had a much lower tolerance towards drinking alcohol as this variant affected their ability to metabolise alcohol. However, how this mechanism works is unknown. When one has had too much alcohol,l like when you’re put in the dentist chair in the circle, the body cannot metabolise alcohol at the rate it needs to, leading to the side effects we all know too well. Such side effects include nausea and throwing up in any sink, toilet, or urinal that can be found in the toilets of the Copper Rooms. The authors posit that people with that particular variant break down alcohol faster, and immediately feel nauseous which discourages them from future drinking.

This research comes at an interesting time, as we are entering a crossroad with our relationship with alcohol, and concerns about our nation’s binge culture have grown. This story has followed from widely reported stories throughout February which found a link between chronic drinking and dementia, that alcohol is more harmful to the brain than marijuana, and concerns about the record high drinking-related admissions to hospitals last year. A predicted 3.1 million people decided to try ‘Dry January‘ this year – an alcohol equivalent of lent where participants forsake alcohol for a month for their health. It’s fair to say that there’s justifiable concern about alcoholism, not only because of the harm towards an individual’s health, but also the social costs of violent alcoholism and the burden of treatment onto public services.

Concerns about our nation’s binge culture have grown

However, we shouldn’t rush to conclude that this gene variant is the solution our alcoholic ailments. As Benjamin Voight told Newsweek, “Alcohol dependence is a complex human trait – … a function of genetic background, environment, and behaviour”. Indeed, this genetic insight is but one piece of the puzzle that must be put together, and it most certainly shouldn’t lead our society to spring the trap of taking a fatalistic approach to alcoholism and dependency. We definitely shouldn’t conclude that ending the social problem of alcoholism is a job for natural selection. Rather, it reflects the reality that drinking alcohol can have severe negative consequences, so much so that humanity is beginning to show adaptations to dissuade people from drinking. Whilst it’s hard to deny the pleasures of having a fun night out, this latest insight now shows more clearly than ever the darker side of our binge drinking culture which students can by shy to talk about.