Why Does Asparagus Make Your Pee Smell?

Our food scientist Jared Levan has solved the mysteries of brain freeze, the emotions caused by chopping raw onions and beans—the magical fruit. Today he takes on the joys of making water after a feast of asparagus.

What is the condition known as asparagus pee?

Just before the onset of the summer, produce heads can be found scouring their local farm stands for the young, delicate stalks of the asparagus plant. Unfortunately, for some, the joys of eating asparagus tend to continue long after the last bite. For many, the flavor may have left the mouth, but the smell is far from out of sight. Many of you refer to what I'm talking about as asparagus pee — the sometimes overpowering olfactory assault that comes in the footsteps of asparagus consumption.

Why does asparagus pee happen?

Blame it on the methyl mercaptan, also known as methanethiol. This foul-smelling, colorless gas is thought to be the cause of the problem, but not in the manner you may think. It was once believed that the methanethiol in asparagus caused the uniquely-scented excretions only in individuals who possessed an enzyme able to digest it. If you had the enzyme allowing you to digest the sulfur compounds contained in asparagus (of which, one is methanethiol), you'd experience the distinct odor upon urination. New research, however, now suggests that all humans may be capable of digesting and breaking down methanethiol — the difference being that only some of us can actually smell it.

How can you prevent asparagus pee?

In the case of either theory, unfortunately, some of you will always be plagued with the strong smell of sulfur whenever you treat yourselves to a couple of raw, cooked or even pickled spears. That being said, there truly is no way of preventing the smell, except maybe a nose-plug or a well-ventilated restroom. Sorry folks.