25 April 2014

The yeast-laden cure for drunkenness: A biochemist's perspective

A recent article on Esquire has begun making the rounds on the internet touting a cure to alcoholic inebriation, allowing the user to drink with less constraint at ever-more-popular beer festivals. In the article, Jim Koch, the founder of the Boston Beer Company and creator of Sam Adams, says the solution is simple: Eat yogurt with 1 tsp of baker's yeast for every drink you plan to have that evening. And it turns out this may make biochemical sense.

Yeasts are well known for their ability to ferment simple sugars into alcohol, but it turns out they can also reverse this process in the absence of sugar. Producing energy from ethanol involves enzymes that are related to the enzymes in our livers, which are responsible for detoxifying ethanol when we consume it. These enzymes are called alcohol dehydrogenase and acetaldehyde dehydrogenase. Respectively, they convert the toxic ethanol into an even more toxic byproduct, acetaldehyde, which is in turn converted into acetic acid. Enzymes then use the acetic acid to create acetyl-CoA for use in other biochemical applications like protein acylation.

As mentioned, baker's yeast and other microbes, such as lactic acid bacteria, utilize similar, evolutionarily related enzymes in order to extract energy from ethanol. Both of these microbes are present in Jim Koch's cure, but I am curious as to which has the dominant effect if both were to be present in equal quantities. Many people may be suspicious whether these microbes could survive the harsh conditions of the stomach, with its low pH; however, many microbes are able to survive this environment (1, 2, 3). In fact, lactic acid bacteria have been isolated from human stomachs (4).

Other fermented foods such as kimchi and sauerkraut could be tested for their ability to metabolize alcohol in the human gut, as the microbes used in these naturally-fermented foods are also capable of detoxifying ethanol (5). The consumption of vinegar concurrently with alcoholic beverages is another intriguing possibility, as the acetic acid bacteria in live vinegar are capable of converting ethanol to acetic acid, and this is in fact how vinegar is produced.

I originally thought that the sheer number of yeasts in Jim Koch's method may be the reason why it "works" (an assumption, given that I haven't actually tried it). 1 tsp of yeast contains approximately 2.8 g, and each gram has approximately 10^10, or 10 billion, cells. This translates to 28 billion cells in Jim Koch's "cure" (6). A good serving of kimchi or sauerkraut also provides a similar number of microbes, at 1 million to 1 billion lactic acid bacteria and yeast per mL (=~1/4tsp), depending on the length of fermentation (78). However, baker's yeast is known to have a highly active acetaldehyde dehydrogenase that is in fact purified for commercial uses (9)!

I suspect that this method may slightly reduce intoxication, especially if eaten with a lot of food that would slow the absorption of the alcohol. And although it would be nice to think there is a magical way to avoid a hangover, the microbes you consumed will likely be unable to help you out. Once the alcohol is absorbed into the bloodstream, it will be largely unavailable to microbes in your GI tract, though in theory they could help detoxify the alcohol byproduct acetaldehyde and send you on your way to recovery.

What do you think? Would you try Jim Koch's yeast and yogurt cure?


UPDATE: Some enterprising reporters at NPR tried it! ... It didn't work (Obviously their sample size is very small, but...). Alternating alcoholic beverages with water worked better, which is a tactic even your grandma may recognize! I suspect that this particular "cure" failed for a couple reasons:

  1. Unless you are consuming only (diluted) distilled alcohol, there will always be additional sugars present for the yeast to consume, and as a result, the biochemical pathways that allow them to uptake and metabolize alcohol may not be activated.
  2. Ethanol is a small molecule and is absorbed quite readily through the lining of the stomach and the small intestines. This process may remove the ethanol before yeasts and other microbes have the opportunity to take it up to consume themselves. 

No comments: