[HoosierBrew]

If this really were valid, then I ought to be able to drink yeasty hefe or wit 'round the clock, right ?  The hangover cause and cure in every glass.

[erockrph]

But doesn't the ADH just do the same thing in your liver anyways?  So for a given amount of beer it would be the same level of acetaldehyde in your body correct?  Of course I suppose this assumes you don't drink MORE because you're not getting drunk...

If there is more ADH (in your GI and in your liver) and the same amount of the enzyme that breaks down the acetaldehyde, you could end up with more acetaldehyde especially if you normally get flushed when drinking.

If you don't normally get flushed, go ahead and try the yeast.  I get a little flushed so I'm not going to try it unless I find out the yeast also provides the other enzyme too.

S. cerevisiae does have aldehyde dehydrogenase enzymes as well. This is why we leave beer on the yeast to "clean up" acetaldehyde after fermentation.

Maybe I'll run a booth selling packets of US-05 at the next beer festival in my area...

[pete b]

I would like to know if this would effect my gut flora before trying it out. I have a "gut feeling" that it could hurt the population of beneficial microbes down there and that's hugely important. But maybe breaking down some of the alcohol might actually help those microbes. Just don't know.

[klickitat jim]

This seems counterintuitive to that article on how the old man who had yeast in his gut was a walking fermentor and drunk all the time...

Call me old fashioned but it just seems that moderation is the only way.

[HoosierBrew]

This seems counterintuitive to that article on how the old man who had yeast in his gut was a walking fermentor and drunk all the time...

Call me old fashioned but it just seems that moderation is the only way.

That's the same thing I was thinking.  +1 to moderation instead of potentially messing your gut up.

[klickitat jim]

Or messing up your friendships, marriage, family, driving record, finances, criminal history, career...

[tschmidlin]

I was asked about this in one of my homebrew clubs, here was my answer . . .

I don't know all of the science behind it, but here is my take.  TLDR version - I'm skeptical.

There are 7 or 8 alcohol dehydrogenase (ADH) genes in yeast.  This is from the fully sequenced yeast strain (S228C), which is not a brewing version but is closely related.  Any bakers yeast or brewing yeast will be very similar, although gene duplications are likely to have happened and so there may be more than one version of these genes.  The activated yeast from the store that the article references will be similar.

Of these ADH genes, most of them are involved with turning acetaldehyde (CH3CHO) into ethanol (CH3CHOH).  A couple of them are suspected in fusel alcohol production.  Only one of them, ADH2, is able to do the reverse reaction and convert ethanol into acetaldehyde.

The purpose of ADH2 is to allow the yeast to use ethanol as a carbon source, so expression of the ADH2 gene is up-regulated in the presence of ethanol.  But yeast prefer to use sugar as a carbon source, so in the presence of sugar expression of ADH2 is repressed several hundred fold.  When dried yeast is made it is grown in a low gravity sugar solution which means there would not be much ADH2 present in the dried yeast to begin with.

Then there is the problem of the environment.  In order for what they are proposing to work, the ADH2 enzyme would have to maintain functionality in the stomach and the GI tract.  The challenge is both the low pH of the stomach and the proteases your body makes to digest food.  It's possible this isn't a problem for the yeast ADH2 protein, but it seems unlikely that ADH2 would be protease resistant and low pH tends to cause proteins to unfold.

So because of the low amounts of ADH2, the low pH, and the protease rich environment of the stomach, I'm a bit skeptical.  I have no idea if it works as he says it does, but if it does I doubt it is for that reason.  A more likely explanation seems to me that after a couple of decades of drinking regularly, Jim's own ADH2 expression levels are high so it is broken down quickly by his body and yeast ADH2 does not play a role.  Maybe we should get some yeast that completely lacks ADH2 as a control and we can give it a try.

[a10t2]

A more likely explanation seems to me that after a couple of decades of drinking regularly, Jim's own ADH2 expression levels are high so it is broken down quickly by his body and yeast ADH2 does not play a role.

A more likely explanation still is that after decades of drinking, he's figured out how to hide it.

[tschmidlin]

A more likely explanation seems to me that after a couple of decades of drinking regularly, Jim's own ADH2 expression levels are high so it is broken down quickly by his body and yeast ADH2 does not play a role.

A more likely explanation still is that after decades of drinking, he's figured out how to hide it.

Probably a combination of both

[tschmidlin]

A more likely explanation seems to me that after a couple of decades of drinking regularly, Jim's own ADH2 expression levels are high so it is broken down quickly by his body and yeast ADH2 does not play a role.

A more likely explanation still is that after decades of drinking, he's figured out how to hide it.

That reminds me of the time I went on a ride-along with NJSP.  The trooper pulled over a guy for speeding and smelled alcohol, but the guy passed every bit of the field sobriety test except the last one.  The last one he failed badly - it is the HGN test and is a physiological response.  I was talking to the trooper and he didn't get it, he said the guy seemed totally fine but the HGN said he was hammered.  So he took him in for a breathalyzer and the guy blew over .20.

[majorvices]

This reminds me of another fact that is little well known. If you eat Hot Krispy Kream donuts they have no calories. This is because the biological response of your anatomical enzymes do not see the calories so they pass right through. You can eat as many as you want, as long as they are hot. I know this is true because I can eat a dozen with no problems.

[klickitat jim]

You crack me up

[Thirsty_Monk]

This reminds me of another fact that is little well known. If you eat Hot Krispy Kream donuts they have no calories. This is because the biological response of your anatomical enzymes do not see the calories so they pass right through. You can eat as many as you want, as long as they are hot. I know this is true because I can eat a dozen with no problems.

I think this is brand specific. I did this with Kwik Trip donuts and now look at me.

[HoosierBrew]

This reminds me of another fact that is little well known. If you eat Hot Krispy Kream donuts they have no calories. This is because the biological response of your anatomical enzymes do not see the calories so they pass right through. You can eat as many as you want, as long as they are hot. I know this is true because I can eat a dozen with no problems.

I think this is brand specific. I did this with Kwik Trip donuts and now look at me.

Must be it.  Dunkin' Donuts didn't do me any favors either. And I've had 'em plenty hot.   

[erockrph]

I was asked about this in one of my homebrew clubs, here was my answer . . .

I don't know all of the science behind it, but here is my take.  TLDR version - I'm skeptical.

There are 7 or 8 alcohol dehydrogenase (ADH) genes in yeast.  This is from the fully sequenced yeast strain (S228C), which is not a brewing version but is closely related.  Any bakers yeast or brewing yeast will be very similar, although gene duplications are likely to have happened and so there may be more than one version of these genes.  The activated yeast from the store that the article references will be similar.

Of these ADH genes, most of them are involved with turning acetaldehyde (CH3CHO) into ethanol (CH3CHOH).  A couple of them are suspected in fusel alcohol production.  Only one of them, ADH2, is able to do the reverse reaction and convert ethanol into acetaldehyde.

The purpose of ADH2 is to allow the yeast to use ethanol as a carbon source, so expression of the ADH2 gene is up-regulated in the presence of ethanol.  But yeast prefer to use sugar as a carbon source, so in the presence of sugar expression of ADH2 is repressed several hundred fold.  When dried yeast is made it is grown in a low gravity sugar solution which means there would not be much ADH2 present in the dried yeast to begin with.

Then there is the problem of the environment.  In order for what they are proposing to work, the ADH2 enzyme would have to maintain functionality in the stomach and the GI tract.  The challenge is both the low pH of the stomach and the proteases your body makes to digest food.  It's possible this isn't a problem for the yeast ADH2 protein, but it seems unlikely that ADH2 would be protease resistant and low pH tends to cause proteins to unfold.

So because of the low amounts of ADH2, the low pH, and the protease rich environment of the stomach, I'm a bit skeptical.  I have no idea if it works as he says it does, but if it does I doubt it is for that reason.  A more likely explanation seems to me that after a couple of decades of drinking regularly, Jim's own ADH2 expression levels are high so it is broken down quickly by his body and yeast ADH2 does not play a role.  Maybe we should get some yeast that completely lacks ADH2 as a control and we can give it a try.

Also, don't forget that there's plenty of sugar available through much of the GI tract. If any yeast survive the trip, wake up, and start eating, they are a lot more likely to eat the food in our gut than the alcohol in our beer.