Asparagus in Urine: Why Does It Smell So Funny?

Asparagus time at last – full of white gold! But when we have eaten asparagus, our urine smells strangely. Why is that?

Every year at asparagus time we ask ourselves: Why does asparagus smell so special in urine? Now we have set out in search of an answer. Our finding: the process behind it has not yet been fully clarified, but a very probable theory blames the sulphurous substances in asparagus.

Asparagusic acid, which is mainly contained in the asparagus heads, plays a special role in this process. When it encounters a special enzyme in the body, it decomposes into its sulphur-containing components, which are then excreted with the urine. And there is really no need to tell anyone that sulphur smells unpleasant.

Asparagus in urine smells: The genes are to blame!

Interestingly, not every urine smells so strange after eating asparagus. Whether the asparagus has an influence on the smell or not is genetically determined. Not all people possess the special enzyme that triggers the reaction. Only about one in two people say whether they had asparagus for lunch when they go to the toilet.

And there is another genetic peculiarity: some people simply cannot smell the sulfurous odor because of a mutation in the gene of an odor receptor – even if it is there. In the asparagus season these people are sometimes really to be envied.

But of course, we don’t let the smell stop us from eating asparagus, because asparagus is healthy!