During digestion, does ethanol react with lipids to form esters, at a significant conversion rate?

Submitted by spamarind_soda t3_1083s4n in askscience

It's well known that having a meal before consuming alcohol (ethanol in this context) slows down its absorption into the bloodstream. A quick google search pegs this at 50% reduced maximum BAC level compared to consuming alcohol on an empty stomach. Without chemistry knowledge, one might be inclined to believe that just about all of the alcohol eventually reaches the bloodstream.

I found out today that ethanol reacts with organic fats (carboxylics only?) to form esters, which do not appear to act like ethanol in the body.

My question is, is this likely to result in a significant decrease in the total amount of ethanol that eventually reaches the blood? If a person ate a fatty meal before drinking, is it possible this could reduce the bioavailability of the ethanol (if that's the right term) by >20%?

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varialectio t1_j3q8948 wrote

Typically, the formation of esters is an equilibrium process able to proceed in either direction.

Alcohol + Acid <=> Ester + Water

To drive the equilibrium to the right (to make an ester in the lab) it is usually necessary to continually remove the water from the mix as it is created. In the presence of excess water as is going to be the case in the body, the equilibrium is going to be well over on the side of the reactants

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bubbastars t1_j3rfw49 wrote

Does sweating (or other forms of dehydration) affect water in the body enough to shift the equilibrium towards the products?

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Uncynical_Diogenes t1_j3rpy8u wrote

Life is the process of homeostasis, or preventing your equilibria from shifting.

You die before any of your equilibria shift very much, because that’s what dying is.

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ScienceIsSexy420 t1_j3roja5 wrote

You'd likely die from dehydration before your endogenous water levels were low enough to push thia reaction to the right enough to form appreciable amount of esters

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doaardvarksswim t1_j3sz0h4 wrote

This needs to be said. Nearly all of life that we know of exists in equilibrium.

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skisushi t1_j3uqstf wrote

Nope. Nearly all death is at equilibrium. Steady state with energy inputs is not equilibrium. Nerves, muscles, etc are constantly utilizing energy to avoid the equilibrium state.

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ScienceIsSexy420 t1_j46v0tj wrote

I'll never forget this question from my Cell Bio final:

Q: what do you call a cell at equilibrium with its environment

A: Dead

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ScienceIsSexy420 t1_j46v04u wrote

I'll never forget this question from my Cell Bio final:

Q: what do you call a cell at equilibrium with its environment

A: Dead

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hifructosetrashjuice t1_j3qdlvs wrote

Even if it occurred in significant amounts, at any rate it'd be all hydrolyzed in duodenum in basic conditions releasing alcohol back (where hydrolysis of fats occurs anyway). It works this way, because alcohol partitions into fat phase and is released from there relatively slowly and liver is good at shredding alcohol

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Coffeinated t1_j3rlegu wrote

If I remember correctly, the reduction in peak BAC stems from the fact that the absorption if alcohol is heavily delayed or rather slowed down, thus flattening the curve. Compare drinking a bottle of wodka on the spot to drinking beer with the same alcohol content (roundabout 5.5 liters of beer) over the course of a whole evening.

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U-Tea t1_j3wcdvn wrote

https://pubmed.ncbi.nlm.nih.gov/15099407/

I think when food is taken before drinking alcohol it reduces the area of contact of alcohol and intestine which causes slow intake of alcohol and higher action of alcohol dehydrogenase. Please refer to the article above.

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CrateDane t1_j3ta6h4 wrote

>I found out today that ethanol reacts with organic fats (carboxylics only?) to form esters, which do not appear to act like ethanol in the body.

An alcohol can form an ester with a carboxylic acid, such as a fatty acid. Ethanol is obviously an alcohol, so that can happen under the right circumstances.

Thing is, when you're talking about fat, usually you're talking about triglycerides or maybe phospholipids etc. In those cases, the fatty acids have already formed an ester with an alcohol. It just isn't ethanol, but instead glycerol. So there's nowhere for ethanol to "attack".

In the process of digestion, those esters in dietary fat are actually broken down by enzymes, but those same enzymes would also immediately break any esters that ethanol might try to form.

In any case, the reaction conditions to form an ester aren't really there in the human body (except when aided by enzymes).

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