Alcohol is eliminated from the body at what rate per hour?
1 Answer
Short answer: roughly 1 unit per hour, as a general rule of thumb.
More precise answer: varies and depends on a lot of factors...
Explanation:
NOTE: In organic chemistry there are thousands of different alcohols: every organic molecule that contains a hydroxyl group (OH-group) essentially is an alcohol. In this answer, for alcohol read Ethanol ,
Although the rule of thumb stated above is roughly workable and acceptable, in reality there are so many different factors influencing the rate of elimination that it is fair to state that more or less every individual has his/her own rate, though they don't vary wildly...
The standard advice commonly given is that your body will break down 1 unit of Ethanol per hour. The clock starts ticking the moment you swallow the first sip. To be on the safe side, you should allow for one extra hour to correct for the slight variations in the rate of breakdown your body can perform.
The moment you swallow your first sip, the drink enters the stomach. Since ethanol is a small molecule and standard metabolite (even tee-totallers process small amounts of alcohol), a small amount is immediately passed through the lining of the stomach into the bloodstream. This can be up to 20-25% of the total amount present, and is dependent on whether there is any food present: the percentage tends to be higher when the stomach is empty.
The human heart pumps the total volume of blood present in your body around completely in approx. 1 minute, so the first sip of your drink will start taking effect in less than that, typically in about 30 seconds after ingestion. The effect will be hardly noticeable at first though: the satisfaction you feel has more to do with the release of Endorphins (Reward System, see MesoLimbic Pathway ).
Eventually the alcohol will enter the small intestine where the rest will be resorbed into the bloodstream. The speed of absorption from the small intestine is higher than that in the stomach, but as it can take a while BEFORE the alcohol enters the intestines, it essentially acts as a ticking time-bomb: up to, typically, two hours after you stop drinking, the concentration of alcohol in your blood will keep rising.
This is the reason experts consider alcohol one of the, if not THE most treacherous drug on the planet. We have lived with alcohol for thousands of years, and as such it is socially accepted, but if it would be invented today it would no doubt be banned straight away.
The concentration of alcohol in your blood is generally referred to as BAC: Blood Alcohol Content. This is the percentage of ethanol in the blood in units of mass of alcohol per volume of blood. In some countries, this is calculated per mass of blood.
The BAC is usually measured in a Blood Test, though more often a breathaliser is used. Though the concentrations of alcohol in blood and breath are different, there is a 1:1 correlation between the two values.
To predict the BAC (EBAC, or Estimated BAC), the Widmark Formula is used:
in which:
- 0.806 = the constant for body water in the blood (mean 80.6%);
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- 1.2 = correction factor;
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It will be clear from this formula that the rate can differ not only between males and females, but on several individual- and situation-related factors, e.g. body weight, DP and SD.
So how is alcohol actually broken down in the body?
It all takes place in the Liver. Liver cells convert (oxidise) Ethanol enzymatically to AcetAldehyde (
In a follow-up step a different enzyme (AcDH, or Acetaldehyde Dehydrogenase) converts this into Acetic Acid, or Acetate, more commonly known as Vinegar. this is a common metabolite and the body has no problem with it, so at this point we can consider the breakdown complete.
The first step is performed by Alcohol Dehydrogenase (ADH) , one of the fastest enzymes known. In most metabolic processes the reaction slows down with the depletion of the substrate, comparable to the half-life decay of Radio Isotopes, but in the case of ADH it is a linear reaction all the way due to the abundance of substrate and the relatively small amount of ADH, rendering the enzyme completely saturated, and therefore working at maximum (constant) speed.
There is not one ADH, there are more: ADH1, ADH4, ADH5, ADH6 and ADH7. each of these have a different affinity for ethanol, and display varying degrees of effectiveness for the reaction. As each individual produces slightly diferent amounts of them, each individual will have a slightly different rate of processing.
Furthermore, different variations of the ADH's exist. These alleles, in particular with respect to the main enzyme (ADH1) differ significantly in their affinity for ethanol, and reaction effectiveness.
These alleles are not distributed equally throughout the world's population: populations that have been drinking for thousands of years generally have more effective alleles than groups that have never, or only recently been exposed to alcohol (e.g. native Americans).
Lastly, there is one more factor worth mentioning: MEOS
This stands for Microsomal Ethanol Oxidising System, and is a "backup" system that is active/activated in persistent (chronic) heavy drinkers.
It is an alternative process that takes place in the SER (Smooth Endoplasmic Reticulum). It uses the CYP2E1 enzyme, which is a member of the Cytochrome P450 class of enzymes.
CYP2E1 also converts Ethanol to AcetAldehyde, but it uses
Wouldn't recommend it as a slimming diet, though....
