Lifted from -Closure-
on the CripplingAlcoholism sub of Reddit.
It's mostly just one man's dream to put a lod of alcohol related science in one place, and so there are some factual errors here and there, but mostly it seems sound.http://www.reddit.com/r/cripplingalcoholism/comments/vzzuq/cas_and_nutrition_ethanol_and_energy/
Okay, I've been meaning to make this series of posts for bloody ages. I just want to give a quick overview of the basics regarding Alcoholism, Ethanol, and one's general Nutrition.
I'm making three types of post:
Please note that I have absolutely zero background in science, or at least zero post high school. If you have any information to add, or correct, please do so in the comments below. Also, I strongly urge that no one ever takes anything I say as medical advice nor information, but rather just as my own personal thoughts. There is obviously a clear difference there, and it is very important to me that this difference is understood.
Ethanol - the 'drinking alcohol' - is the psychoactive drug that we all love/need to imbibe, whether recreationally or as self-medication or for whatever purpose.
Besides being psychoactive, it is also a potent fuel. This is pretty unique as far as drugs go.
A Calorie is a measure of energy. What we call a 'Calorie' is actually a 'large calorie' - written as Cal or more commonly as kcal - which is a measure of a thousand 'small calories' (written as cal).
One large calorie - or, in normal speak, one Calorie (1 kcal) - is the amount of energy needed to increase the temperature of 1 kilo of water by 1 degree celcius.
On a gram by gram basis, you get the following energy from the following fuel sources:
- 1 gram of Fat=9 Calories
- 1 gram of Protein=4 Calories
- 1 gram of Carbohydrate=4 Calories
- 1 gram of Ethanol=7 Calories
and, as 7.9 grams of Ethanol equals 10ml of Ethanol:
- 1ml of Ethanol=5.5 Calories
So, in a fifth (750ml/25 fl. oz.) of straight 80 proof liquor (40% Ethanol/~60% Water), you'll get:
- 750ml x 0.4=300ml Ethanol
- 300ml x 5.5 Calories
- 1650 Calories
It's important to note though that whilst human energy sources are measured in Calories, they are certainly not equal in the sense of how the human body uses them, or even can use them.
Typically (and in layman's), the body uses Glucose (or Ketones) for energy. Consumed Fat/Protein/Carbohydrate (F/P/C) will be broken down, and a large proportion of these energy sources will be converted into Glucose, as well as Glycerol and Free Fatty Acids, etc, with their levels increasing in proportion to the amount of Calories consumed. When there is an excess of Calories consumed, that's when the body mashes the excess together and stores it as Fat (Adipose Tissue).
Ethanol, though, is used differently by the body.
First, when Ethanol is present, this is what the body (via the Liver, mainly) switches to as its primary energy source. That roughly means that other energy sources (e.g. F/P/C) will not be used till all of the Ethanol has been metabolised, if they are used at all.
Secondly, whilst Ethanol isn't in itself toxic (well, kinda…), it's first metabolite (what it's broken down into) - Acetaldehyde - is… and, relative to alcohol, I've read that it's ~30 times more toxic.
Ethanol is broken down by the enzyme Alcohol Dehydrogenase into Acetaldehyde.
Acetaldehyde is toxic, an irritant, and a carcinogen. Put it in humans, and it will fuck their shit up. It causes nausea, vomiting, headaches, dizziness, confusion, fatigue, incoordination, memory impairment, swelling, flushing of the skin, etc. It's one of the main causing factors of hangovers.
Luckily, the body is prepared for this metabolite, and quickly tries to break it down before too much damage is done. People have argued this is why the liver prioritises Ethanol over other fuel sources (i.e. humans that didn't prioritise Ethanol all died off). The body also uses antioxidants, such as Vitamin B1 (Thiamine) and Vitamin C, to deal with the Acetaldehyde (hence why these vitamins help with hangovers but, more importantly, this a reason for why CAs can incur a deficiency in these vitamins).
But, again, anyway:
Acetaldehyde is broken down by the enzyme Acetaldehyde Dehydrogenase into Acetic Acid.
Actually, I'm going to take a break here to go back to Acetaldehyde.
I've mentioned what it does to the body. If you're familiar with Alcohol Flush (e.g. Asian Flush/Asian Glow), where a person's face will go bright red after drinking alcohol, this is a reaction due to there being too much Acetaldehyde within said person's system.
This is commonly seen in Far Eastern Asians due to a 'defective' allele or absent isozyme of (at least) one of the aforementioned first two enzymes responsible for alcohol metabolism.
Most commonly this is a problem that is found to lie with the second enzyme involved - Acetaldehyde Dehydrogenase - thus meaning that the Acetaldehyde is not metabolised fast enough into Acetic Acid, causing a (relatively rapid) rising accumulation of Acetaldehyde. However, the issue may lie with the first enzyme involved - Alcohol Dehydrogenase - thus meaning that Ethanol is too rapidly metabolised into Acetaldehyde, again causing the aforementioned (relatively rapid) rising accumulation of Acetaldehyde.
The long-short of it is that, besides the flushing reaction, other symptoms (i.e. many of those that one would associate with a hangover) will also affect the sufferer. Unsurprisingly, this typically leads to a lower rate of alcoholism amongst those affected by this reaction… though, in my own experience, it rarely ends their night.
If you don't suffer from these reactions but want to know what it all feels like, get yourself a prescription to Disulfiram (Antabuse) or Calcium Carbimide (Temposil) [FYI, the latter is a safer medication from all reports I have read]. These drugs interfere with the function of the second enzyme - Acetaldehyde Dehydrogenase - meaning that once Ethanol is metabolised into Acetaldehyde, it hangs around for far longer and in far larger quantities (~750% larger) than it would normally. With these drugs in your system (I believe a dose of Antabuse is effective for up to 12 hours, Temposil for up to 8 hours), and after an exposure to Ethanol, you should start to feel very hungover within ~15 minutes. Personally, I think these drugs are dangerous and change nothing within the mind of an addict, but if you are thinking of quitting they do help some people… you'd have to be a masochist to take such drugs on the regular and still drink, assuming they affect you as intended.
Anyway, back to the metabolic route:
Ethanol --> + Alcohol Hydrogenase --> Acetaldehyde --> + Acetaldehyde Hydrogenase --> Acetic Acid (aka, Acetate)
Acetate is harmless, and is then further broken down into Acetyl-CoA, which the body uses for energy or to produce Ketones. This is where the majority (let's say ~95% for simplicity's sake) of used Ethanol calories end up.
Whilst the above all occurs at the liver, Ethanol is also metabolised (in far smaller quantities) by other parts of the body, such as the Pancreas and the Brain, which all (just like the Liver) sustain damage by doing so.
Note: besides the enzymes I have listed above, CYP2E1 is another enzyme involved in the process of metabolising Ethanol within the Liver.
Whilst it is commonly assumed that the liver can only metabolise x amount of alcohol over a set time as standard, x certainly varies between people, and chronic alcoholics have been shown to metabolise Ethanol at a rate as high as (I believe) 4 times their 'normal'. This is mostly due to elevated levels of said enzymes.
Back to Calories… like I said, about 95% of used Ethanol Calories end up as Acetate. Excess Acetate cannot, and does not, end up as Fat. It, however, remains the body's primary source of energy, thus entailing that any other present sources of energy (e.g. F/P/C) maintain their 'excess' status until they are dealt with.
Less than 5% of Ethanol Calories can end up as stored fat, but in practice this doesn't really happen, particularly as Ethanol metabolism is a difficult process that uses a lot of energy itself.
Net result: if your diet solely consists of Ethanol Calories, and you consume (even well) over your needed level (e.g. 3000 Calories of Ethanol, compared to your needed 2000 Calories a day), you will not gain weight.
However: if you add in other energy sources, and there is an excess of Calories, then this excess (from the other energy sources) will be ultimately be converted to stored fat, or it will simply be passed as waste.
Also, keep in mind that I am strictly only talking about Ethanol calories when it comes to Alcoholic beverages. If your source of Ethanol contains other energy sources (e.g. Carbohydrates), then these other energy sources will be treated separately. Thus, drinks like sugary cocktails or beer or whatever are far more likely to cause weight gain than drinking low sugar alcoholic drinks like wine, or (basically) nil sugar alcoholic drinks like straight liquor.
Anyway, that's what I wanted to write about Ethanol being used as a source of energy.
If I have made any errors, or you want to add anything else, please let us all know below in the comments.