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The effects of alcohol on the human body

The polarization within society that we’re currently experiencing likely has no parallel in the history of modern civilization. One of the contributing factors to its escalation is undoubtedly the internet, but that’s a topic for other platforms. Today, let’s focus on alcohol, which also divides society in many situations.

Bartenders in today’s establishments are capable of a multitude of skills. From the impressive twirl of a bar spoon to the flawless pouring of liquid from a larger shaker to a smaller one, to the history of Negroni. Other bartenders serve vodka with an energy drink to a guest at four in the morning, who, after one more drink, starts to lose articulation and balance.

From a chemical standpoint, every bartender in any establishment serving alcohol does the exact same thing, regardless of technique, hospitality, or anything else. They serve the same molecule but in different flavors, aromas, and textures. Every bartender should be aware that alcohol intoxicates the human body. Nearly everyone working in the hospitality industry has probably encountered an intoxicated guest. I was fortunate enough to have been told before I started learning about bartending and grabbed my first glass: “Never serve an intoxicated guest! You don’t want to be responsible for what might happen to them!” Of course, people’s tolerance to intoxication varies; some handle it better than others. It’s all due to chemical and biological processes that occur in our bodies when, for example, we sip on a dry Martini at our favorite bar.

Recently, I’ve been reflecting on all the workshops I’ve attended and realized that apart from learning about the history and tasting a particular brand of alcohol, none of them covered how alcohol affects the human body. Not one. I believe these kinds of details are missing from similar workshops, except for the label on the back of the bottle saying, “Drink responsibly.” It might sound exaggerated, but if we pride ourselves on hospitality, exquisite mixing techniques, or telling fantastic stories, let’s also be knowledgeable when explaining what alcohol causes besides euphoria, a surge of emotions, and subsequently, less pleasant experiences.

Water, sugar, yeast

Let’s take a closer look at this. Alcohol, or ethanol, is a molecule present in every alcoholic beverage. To create any such beverage, you basically need three things: water, sugar, and yeast. It’s eerily poetic that every drink we love has the same foundation. Suddenly, debates about who first distilled vodka or which country produced the first whiskey seem quite unnecessary.

Behind ethanol are yeast, which are literally everywhere around us. Hence, it’s no wonder that alcohol has been with us since the dawn of civilizations. If we were to define how ethanol is formed, we could comfortably say that it’s a byproduct (quite literally a waste product) of yeast fermentation.

Consider the almighty yeast of ancient civilizations. The Mayans or Aztecs were able to ferment corn into something resembling beer. But how, when we know for certain they didn’t have the technology to control corn fermentation?

Fermentation is basically the transformation of simple sugars like glucose into alcohol. In beer or whiskey production, barley is used, but it needs to be “primed” by sprouting to enable fermentation. Sprouting breaks the outer shell of the barley, where the important enzyme called amylase is stored – a crucial enzyme that breaks down starch into glucose, allowing the yeast to feast. However, amylase isn’t only found in barley but also in the human body, including our saliva. This means that if we wanted to make beer at home, theoretically, all we’d need to do is hold grains of barley or corn in our mouths for some time, spit them into a bucket, add water, and wait for nature to take its course. Ancient civilizations used this method.

How much alcohol is too much?

Let’s skip processes like distillation or filtration and focus on the final product and its effects after alcohol consumption. The brain has an amazing ability to filter what it receives, and ethanol falls into this category. But how do we recognize if someone is drunk or not? Apart from the mostly visible effects of intoxication (which might not be noticeable in some individuals), we can quite easily determine this through breath tests measuring alcohol content in the blood. For instance, 0.3% blood alcohol concentration (BAC) in a breath test means your body contains 0.3 milliliters of ethanol per 1 liter of blood, which, by the way, is something like a drop of Angostura bitters in an Old Fashioned cocktail. This limit is relatively harmless, and the effects of intoxication are hardly noticeable. Between 0.3% and 1% BAC, a person experiences euphoria, and their gait starts to become a bit unsteady.

According to most experts, the problem arises at the threshold of one percent BAC, although the impact of alcohol on the human brain remains somewhat mysterious because we still don’t definitively know which parts of the brain it affects. However, the general consensus is that when alcohol reaches the brain, it first visits the frontal lobes, specifically the frontal cortex. These are responsible for controlling human behavior, judgment, rational thinking, and motor coordination. Hence, it’s sometimes very hard to decline a drink when we have around one percent BAC because our frontal lobes have taken quite a hit and become paralyzed. If a person decides to continue, evident signs of intoxication become noticeable. Naturally, all these effects are highly individual. Around three percent BAC, we can talk about alcohol poisoning, and symptoms such as vomiting or delirium set in. Sadly, if a person insists and pushes their luck, they might reach the four percent BAC limit, which is fatal for the human body, as there’s a high chance of falling into a coma. At five percent or more BAC, there’s a fifty percent chance of death.

That’s the general understanding of alcohol levels in the blood. But what happens when ethanol molecules pass through the frontal brain? When the frontal brain takes a hit, the molecules spread further and affect the midbrain. This area is crucial in controlling emotions, and the legendary saying “In wine, there is truth” might have its roots here, as this is where we truly see how a person feels and what they experience. We’re operating around 1.5 to 2 percent BAC here, and the chance of slipping into unconsciousness increases. Subsequently, with further consumption, ethanol reaches the last part of the brain: the brainstem. The brainstem is the oldest part of our brain evolutionarily speaking, where activities essential for life, like breathing and swallowing, occur. If a person gets to this point, it can have catastrophic consequences and lead to death.

Veisalgia or “hangover”

Some experts claim that the effect of ethanol on the brain starts from the top, meaning it begins by paralyzing the cortical brain (outer surface) and then gradually moves down to the lower parts of the brain. The first problem we notice the next day after drinking is feelings of nausea, headaches, and a sort of body-head non-cooperation. Recently, I attended a lecture by a renowned chemist, scientist, and Slovak Technical University professor, Peter Szolcsányi, which became one of the sources for this article. Among other things, he explained that a “hangover” has a scientific term. Veisalgia is a compound word: one part originates from Norwegian, denoting sickness after heavy drinking, and the other, from Greek, meaning pain. With veisalgia, we initially feel extreme dehydration because alcohol is a diuretic. Next, we have hypoglycemia, meaning reduced glucose levels in the body, leading to fatigue and ravenous hunger, usually satisfied by unhealthy food combined with sweetened beverages. It’s a natural defense mechanism that genuinely helps. Headaches during veisalgia can result from various factors such as hypoglycemia or the brain beginning to swell. And as we know, the skull doesn’t expand, hence the immense pain. If you’ve ever heard that alcohol kills brain cells, it’s precisely at this moment because cells can’t withstand the pressure from the brain against the bone and start to die off. It’s important to note that this brain swelling primarily occurs during binge drinking, meaning the body ingests an enormous amount of alcohol in a relatively short time. However, what makes a person feel unwell after a hangover isn’t the ethanol itself. Ultimately, ethanol causes euphoria in smaller quantities. The problem lies in the byproduct when ethanol breaks down in the body. This is when a poison is created that the body can’t eliminate, and that’s acetaldehyde. Thankfully, we have an enzyme in our bodies called aldehyde dehydrogenase that breaks acetaldehyde down into acetic acid, which the body can eliminate without issues, although sometimes it takes what feels like forever. Paradoxically, the advice of having a “hair of the dog” in the morning somewhat counteracts veisalgia; it partially prevents the breakdown of acetaldehyde and makes us feel better. Again, all the above-mentioned processes are individual, depending on genetics, diet, age, or weight.

Another interesting point from the aforementioned lecture, which you might have heard somewhere, is that some Asian populations have a genetic mutation that prevents their aldehyde dehydrogenase from functioning correctly, making it difficult for them to metabolize alcohol, and they’re more quickly affected by veisalgia. For instance, even people who turn red after alcohol consumption might have some issue with this enzyme, as it doesn’t break down acetaldehyde as it should and irritates them.

It’s crucial for people in the bar and hospitality industry to realize that we have the power to impact people’s lives positively or negatively. As Uncle Ben said to a well-known superhero, “With great power comes great responsibility.”

Dominik Tapusik

Written by Dominik Tapusik

Dominik Tapusik is the bar manager at Bratislava's Sky Bar & Restaurant and a co-founder of the initiative We Host You. He has a deep love for all things related to gastronomy.

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