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Asparagus Odor

October 27, 2010

Genetics influences whether you smell a distinctive odor in your urine after eating asparagus.


Explaining asparagus pee…I’m Bob Hirshon and this is Science Update.

Many people, but not all, smell a distinct odor in their urine after eating asparagus. Now, researchers at the Monell Chemical Senses Center in Philadelphia are finding out why. Marcia Pelchat and her colleagues found that some people don’t produce the smelly asparagus by-product, while others can’t smell it. The latter was linked to a variation in their olfactory genes. Pelchat says this insensitivity to one particular odor is called a “specific anosmia.”

MARCIA PELCHAT (Monell Chemical Senses Center):
And the suspicion is that everyone has a few of them. So that everyone has his or her own sensory world.

She also notes that the asparagus odor is a sulfur compound, similar to the rotten-egg-like odor added to natural gas so we can detect it. And it’s worth finding out if people who can’t smell asparagus pee also might be less likely to notice a gas leak. I’m Bob Hirshon, for AAAS, the science society.