The Stinky Truth About Asparagus

Photo by Ginny Braud

The culprit.

I'm just gonna put it out there. What is with asparagus pee? It's an age-old question (okay, maybe not). Novelist Marcel Proust wrote in 1913 that asparagus "transforms my chamber-pot into a flask of perfume." Eau d'Asparagus? I'm not quite sure what passed for perfume in France in 1913, but yikes.

After having asparagus with dinner a few nights ago, it really got me thinking. So what causes asparagus pee?

To solve the mystery, I consulted Jennifer Doctorovich (for real), a nutritional therapist in Houston. She reports, "That rather fragrant smell from our urine is from the sulfurous amino acids that create a chemical reaction when we eliminate. When asparagus is digested it is known to produce mercaptan (or methanethiol) which also gives rotten eggs and skunks their smell."

If you're thinking, "What the hell is 'asparagus pee?'" then you're part of the 50 percent of the population that just can't smell it. Lucky you! Doctorovich says, "The interesting fact is that while we all produce it, genetics has played a bit of a stinky joke on us: Some people can smell it while others can't."

In 1980, an article published by The British Medical Journal called the ability to detect the odor "a genetically determined specific hypersensitivity." The brutal part is that the guys who came to this conclusion conducted an experiment that required innocent people to sniff pee samples. In 1702, Louis Lemery wrote in his book A Treatise of All Sorts of Foods "[Asparagus] cause a filthy and disagreeable smell in the urine, as every Body knows." As it turns out, not everybody knows. Doctorovich concludes, "Basically, stinky pee is genetic (50/50) and it depends on whether you have the nose for it or not."

As for Proust's favorable opinion of the asparagus effect, you couldn't pay me enough to dab it behind my ears.

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