Friday, June 22, 2007

Beer is bad? NEVER!!!! OK, maybe

A lot of chemistry blogs (many of them are very good) include updates from the literature. These are papers that are important in certain fields or just interest the blog author.

Recently, one of the (eh-um) "journals" I read had an interesting article about a dangerous chemical in beer. OK, the "journal" is Brew Your Own magazine, but it was still a well written and interesting article.

I'm a big fan of BYO magazine and It is a great publication for those of us interested in learning everything we can about our favorite hobby.

The article was part of the "Help Me, Mr. Wizard" feature. The articles in BYO magazine are great, but the "Ask Mr. Wizard" feature is my favorite. Mr. Wizard, Ashton Lewis, knows what he is talking about, but (and this is most important) he also researches what he says.

In the latest issue (which I have read completely and will proceed to read again), Mr. Wizard was asked about the dangers of tyramine in beer and the differences between draft beer and bottled beer.

For the most part, Wizard Lewis doesn't shy away from technical terms, but there is nary a chemical structure to be seen. That's OK. That's where this blog comes in.

Tyramine is formed when the amino acid tyrosine is decarboxylated by some bacterial enzymes, namely lactic acid bacteria.

Tyramine is not a problem for most people since monoamine oxidase enzymes catalyze the metabolism of tyramine. However, people taking monoamine oxidase inhibitors (MAOI) have difficulty dealing with tyramine.

The result is high blood pressure and possibly a stroke.

The Mr. Wizard response goes on to explain that tap beer has a higher chance of containing dangerous amounts of tyramine. Commercial bottled beer has a nearly zero risk thanks to pasteurization. Kegged beer and homebrew beer are not pasteurized and run the risk of harboring the offending bacteria.

Tyramine is also found in other foods.

The bottom line is avoid tap beers and homebrew if you are on MAO inhibitors.

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