How did we evolve to enjoy alcohol?

Fast food companies know exactly how to push our evolutionary buttons. We’re all here because we evolved to favour calorie-dense foods like sugar, fat and salt. So it’s easy to see why we’re so tempted by McDonald’s asking us to Supersize our meals. 

This is what’s known as ‘evolutionary mismatch’. Drives that would have helped our ancestors survive (like eating lots of sugar when they found it) that are now working against us in the present.

But how does alcohol get its hooks into us? It’s not so easy to see the benefits it provided our ancestors. Because it’s so easy to overindulge, many of us are quitting or reducing alcohol consumption. Like sugar, fat and salt, in excess it can contribute to disease and injury risk. Perhaps understanding our historical relationship with booze can help us make choices which replicate the benefits we get from alcohol, while avoiding the alcohol itself.

It’s our monkey ancestors’ fault

Robert Dudley (and others) have proposed that our primate ancestors who liked the smell and taste of fermenting fruit might have gained an evolutionary advantage. Fermentation is the process by which bacteria begin to break down foods, digesting them, and in some cases (like that of cheese) mking them easier for us to digest.
Fermenting fruit produces sugars. It’s thought that developing a taste for these sugars might have kept us alive directly (the calories) and indirectly (a risk of being drunk and defenseless probably favoured the primates who consumed the fermented fruit in groups, and thus were more social).

You’re more at risk if you’re of European descent

At the dawn of modern civilization, around 5-10 thousand years ago, two distinct schools of ‘not dying from water borne diseases’ emerged. East Asia favoured boiling water and making tea. Further West, people favoured fermenting alcohol. 

There are some theories for why these two approaches dominated in their geographical regions. A long-term effect which many of us now carry is a tolerance to ethanol (which is a poison). Although it doesn’t always feel like it when we’re in the throes of a hangover, many of us carry genes that help us produce more alcohol dehydrogenase (ADH) which breaks down ethanol.

Naturally, being human, the ability to do anything fun ‘more’ means we often do it to excess. And in a society where consumer products are easy to access, this means alcohol problems. 

Want to spot someone (likely) carrying the genes for higher alcohol tolerance? Look at their eyes. Lighter coloured eyes are linked to these genes. And it’s no surprise that both a history of using fermentation into alcohol to purify water and lighter eyes are most prevalent in Europe.  

Our failure to connect the dots likely affected our genes

In 1854 – not much more than 100 years ago – there was a major cholera outbreak in London. Although humans had been using alcohol to purify water for at least 4,000 years at this point, they didn’t actually know they were doing so. Incredibly, the medical establishment still believed that disease was caused by bad smells, which it was thought denoted some contamination of the air. 

Fortunately, in a striking example of use of the scientific method, a fellow named John Snow was able to identify the source of the cholera outbreak to a pump in Broad Street. He did this by mapping cases of illness (most were those using the pump as their main source of water). The final clincher was that there was only one area in the vicinity completely free of cholera cases – a local brewery, whose workers were provided with a beer ration for themselves and their families. 

This failure to connect the dots between fermentation and water purification probably led directly to our genetic tolerance to alcohol. We didn’t know why we were drinking it. Just that people who liked the taste of alcohol tended to get sick and die less often.

The earliest alcohols may not have been very alcoholic

Fermentation involves tiny bacteria consuming fruit or other foods and completing their full lifecycles. The fact that these organisms digest our food first affects how we respond to it. One of the indicators of the presence of live, helpful bacteria purifying the water was a carbonation. You can see this naturally occurring carbonation effect in fermented drinks such as kombucha. It’s likely that people believed that these bubbles were, in themselves, the aspect of the drink that made it safe and healthy. For at least 200 years, people have been adding their own carbonation (completely organism free) to beverages to replicate this effect, often in ‘tonics’ and other beverages that were sold as healthy or medicinal.