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Alcohol and its effects on the body

Alcohol is a poison. The body mounds specific defenses to combat the effects of alcohol, and is able to keep up with this toxin at a rate of about 1 drink an hour. The following is a conversation about what happens when you drink more.

As the stomach encounters and identifies alcohol, it and the liver release an enzyme called alcohol dehydrogenase. This steals a hydrogen molecule off of alcohol and leaves acetaldehyde. This molecule, while not intoxicating to the body, may contribute to the “hangover;” a poorly understood phenomenon. Young men have 70-80% greater enzyme activity in the presence of alcohol than women, but this deteriorates slowly until age 55-60, where they produce less of the enzyme than their female counterparts.

A second enzyme, aldehyde dehydrogenase, bats cleanup and helps remove the acetaldehyde. Some people, including about one third of the Asian population, have a mutation in the amino acid chain that prevents it from cleaning up the acetaldehyde. An excess of this molecule causes skin flushing, dizziness, extreme nausea, and sometimes palpitations.

Drugs like Aspirin, when taken before drinking, inhibits alcohol dehydrogenase, which ironically increases acetaldehyde and the eventual “hangover.”

The challenge for the body becomes how to deal with the alcohol before it hits the small intestine, where it has 200 sq. meters of surface area to absorb. Eating while drinking helps the body do this. Food in the stomach activates the pyloric sphincter, which closes off the stomach from the small intestine. This keeps the alcohol in the stomach, where it doesn’t absorb well and the body has time to convert it. When only liquid is in the stomach, it passes more freely into the small intestine. The stomach in this case is responsible for 20% of the absorption, and the intestine for 80%. Once alcohol hits the small intestine, the body only has one trick left to eliminate a poison, and hopefully you brought an extra set of underwear.

When it comes to actual drinking, higher ABV doesn’t always mean quicker intoxication. Up to about 20% ABV, the body passes alcohol though to the small intestine rapidly. Above that, as in shots of hard liquor, the body tightens the pyloric sphincter and slows absorption. So shots sit in your stomach for longer, like a time release. Later, they can hit you harder than you anticipated. This is why you can take a large number of shots in a short period of time. This is also why that can kill you. Add to that the fact that rapid consumption of alcohol postpones the maximum BAC lever by 2 hours (instead of 30 min. in social drinking), and you have a recipe for a surprise. You keep getting drunker long after you decide you have had enough.

Larger people can hold more alcohol than smaller people. More tissue means more space to store alcohol while the body tries to metabolize it. Women tend to carry a higher body fat percentage than men, and since adipose (fat) tissue carries less water than muscle tissue, it doesn’t have as much ability to dilute the alcohol.

Alcohol does not kill brain cells. It shrinks the brain over long term, but doesn’t kill the cells. It does, however, slowly kills liver cells. When you drink, your brain cells remain more or less unchanged. It’s the neurotransmitters that are affected. Alcohol gets in between the cells and blocks glutamate receptors, which are excitatory, and actually increases GABA receptor activity, which are inhibitory. As more alcohol works its way in between the cells, the brain, literally, gets slower. At a high enough dose, alcohol actually mimics the neurotransmitter GABA, can bind to the cell, and causes a semi-permanent inhibitory response. The body, among other things, slows its breathing until it eventually stops.

While everyone is aware that alcohol affects the brain, it also affects other parts of the body. At low doses, alcohol increases the heart rate. At high doses in health young adults, it causes EKG irregularities. In the endocrine system, it affects the pancreas. In the presence of alcohol, the pancreas over-reacts to the presence of simple sugars and carbohydrates, and over produces insulin. As any Type 1 diabetic will tell you, they have to be really careful about what they eat when the are also having booze. The low sugar levels, in addition to dehydration from the kidneys trying to clean up the blood all night, along with the acetaldehyde mentioned earlier, is likely the cause of the “hangover.”


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