Why is the human body able to extract energy from ethanol alcohol?

Question

Throughout the many thousands of years of our species evolution, presumably we wouldn't have frequently encountered & consumed alcohol. Why then have our bodies evolved to be able to extract energy from it? I also read that we can obtain more energy from it per unit weight than sugars.
Are the liver enzymes that metabolise alcohol the same ones which metabolise sucrose/fructose? Is alcohol classed as a carbohydrate like sugar?
(I have never studied chemistry or biology).

Answer 1

Ethyl alcohol can be classified as one of the sugars....basically a carbohydrate and in that sense is already broken down....from the 4 or 5 or 6 carbon sugars it is a 2 carbon sugar. All students of biochemistry/physiology know that sugars (the 6 carbon ones like glucose, fructose) when broken down enter the Kreb's cycle as two carbon compounds which are very close to ethyl alcohol. So the body IS able to get calories out of alcohol, but it is the wrong kind....too much of it at one go and that too with the intoxication effect of alcohol....so that nothing constructive can be done with it. I mean you are not able to usefully burn it up by working.More serious is when the liver tries to store much of it in its own cells leading to fatty liver disease and cirrhosis...a sequel to alcoholism. Depending upon the way the liver breaks it down it leads to three states of post alocoholic moods - all extremes - relaxation, or restlessness and outright arousal by way of dancing and singing (or in the worse type of reaction - bar room brawl).That is why alcohol has never been (not can be) the staple food for any race or community in the world.

Answer 2

First of all, metabolism is almost ridiculously complex. Turning sugar into energy and carbon dioxide is a process of about a zillion steps. Link 1 is a chart, with each dot being a different step in the chain, if you want to be confused/impressed.

The reason I bring this up is that if any of the things that are intermediary steps show up in your food, then those are just as digestible as sugar. They just get plugged in and off they go. Handy.

But it's not all about sugar, either. You would be surprised how many things your body can get energy out of - fats, proteins, sugars, alcohols... there's a reason why just about every living thing on the planet can be found on a dinner plate in a human restaurant somewhere! It is a terrific adaptive advantage to get energy from so many sources: when other people are starving, you can just eat something else.

And so it goes with ethanol. Ethanol actually DOES occur in nature, though not usually in as huge amounts as we consume it. Just about all fruits have very small amounts of ethanol, and fruits that are a bit past their prime can actually ferment right on the plant. It's quite possible to get a 'bad' batch of berries and become drunk!

Such an experience was probably what started the whole winemaking industry to begin with. And if you think THAT'S weird, you REALLY don't want to know how some cheeses were discovered...

Answer 3

There are many types of sugars and many types of alcohols. You may be confusing alcohol related news items for automobiles with that in the human body.

Like any food, the body consumes it and uses it as fuel, if it's a source of energy. Alcohol isn't a sugar because, basically, it's made from sugars and converted into alcohol. Usually, it's termed as empty calories.

In fact, in beer production, the grains are starches which enzymes convert to sugar before the yeasts convert it to alcohol. Then when the mixture reaches a natural level of around 14%, if it's allowed to get that high, the alcohol content kills the yeasts that created it.

Answer 4

First you must understand that alcohol has carbon, hydrogen and oxygen, assembled. Our body enzimes (which are proteins with a function, that do things in our metabolism) break the alcohol and treat it like a sugar, that is to say, alcohol is broken into small pieces or units and each unit is used independently. This is actually what happens with everything we eat. We can obtain more energy because it doesn't break so easily, it takes longer, and so it acts like a reserve.

Answer 5

If I remember well some nutrition lectures ( from years ago), energy (calories)comes from the break down of chemical bonds. To each bond , a specific energy is released. However I remember perfectly being taught ( with the biochemical explanation_ which I can't really remember) that drinking alcohol provides the body with what the lecturer call "empty calories". what he meant was that calories are produced but unusable for efforts. Hence alcohol makes gain weight and hangover but certainly not usuable heat.

Answer 6

When cooking, swap out the butter for one of these brilliant.

Answer 7

Ethanol is not a rare substance in the human diet. Most ripe fruit probably contains some. I've always thought of it as a carb, but I can't answer the enzyme bit, sorry.

Answer 8

I thought we used the sugar for energy

Answer 9

Nosh on baked carrot chips as an alternative to greasy potato chips.

Answer 10

Eat in front of a person rather than a screen. It cuts down on mindless eating and makes you more accountable for each nip.