Why Your Urine Hates Asparagus

When pre­paring a meal for a room full of guests, you may want to choose another vege­table.

Asparagus is Unfriendly


There are reasons why asparagus will not be a crowd pleaser. We assume every human body functions pretty much the same. They don’t always do so. Some­times things happen we cannot easily explain. Take biochemical reactions to certain vegetables.

Does Your Urine Hate Asparagus?

Some individuals notice a putrid smell during urina­tion after they ingest vegetables within the brassica family. A subset of men and women have something called tri­methyla­minu­ria.

This condition inter­feres with the break­down of a chemical called tri­methyla­mine in choline-rich foods like asparagus or cauli­flower (47 mg/cup), broccoli (30 mg), Brussels sprouts (17 mg) and cabbage (7.5 mg).

But what about people who only have a fetid reaction to aspara­gus? It turns out there is a chemical unique to this vege­table, fittingly called aspara­gusic acid.

Studies are incon­clu­sive because some partici­pants notice their own foul urine, while some smell it in others but not themselves. Remaining indivi­duals have no idea why we are even talking about this.

This is not a wholesale disparage­ment of the vegetable. The nutrition within asparagus is undeniable. Compounds in asparagus root called steroidal glyco­sides may help reduce inflam­mation.

Asparagus also contains calcium, magnesium, and iodine. It is an excellent source of folic acid, vitamins A, C and E.

Malodorous After Party

Scientists investi­gat­ing this olfac­tory phenome­non believe that some people convert aspara­gusic acid into a sulfur com­pound similar to rotten eggs with other pungent notes.

Only about one-quarter of the popula­tion appears to have the special gene that allows them to smell the sulfuric com­pounds emitted by nearly everyone else. This can be awkward. You may be the individual unknowingly stinking up the dinner party. It is not harmful, just off-putting.

If your urine is smelly after eating aspara­gus, you are not alone. What you or others smell is paradoxically common and un­natural. So when pre­paring a meal for a room full of guests, err on the side of caution. Choose a vege­table other than aspara­gus. Or stock up on bath­room air freshener.

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Updated: Oct 23, 2022

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