Why Does Pee Smell Like Asparagus?

Delicious, asparagus. Until it comes back into your nose at full force afterwards, this time via your urine. A smell reminiscent of a bouquet of flowers you should have thrown away ages ago. And that’s just one observation, because everyone associates asparagus pee with something different.

Everyone? No, not quite. Strangely enough, it turns out that only about forty-five percent of people can produce asparagus pee. A matter of genetics. There are even known cases of women who ate asparagus and never had asparagus pee until they were pregnant. It turned out that their child carried the gene, and that the odor-producing compounds they produced were excreted through the placenta!

Asparagus pee: distinctive and pungent

And there’s something else. Apparently, not everyone can even detect the smell. The writer of this piece, an asparagus pee producer, simply can’t imagine that. That’s how it is with people like us. The smell is so distinctive and pungent; how could you miss it?! Enter anosmia: the inability to smell. One study states that as many as seventy-five percent of people are unable to smell asparagus pee. (Another study, however, shows that everyone can smell the odor of asparagus pee.)

Rottenness

So, the smell resembles rottenness—and that’s not so strange, because asparagus produces the sulfur-containing substance asparagusic acid. When we take it into our bodies, the substance is broken down and converted. Six sulfur compounds, including methanethiol, are the culprits; after eating asparagus, they are suddenly present in our urine in much higher concentrations than usual. That explains why people have asparagus pee. But exactly what’s going on with the people who don’t have it is still unknown. To be continued!

Also read:

• This is why your wine sometimes smells like farts
• Buying asparagus: pay attention to this
• The difference between white, green, and purple asparagus