Have you recently eaten asparagus and noticed that your wee smells funny? Or have you heard about the phenomenon and wondered why it doesn’t affect you? Well, it is thought that the prime suspect for this pungent smell is due to the metabolism of asparagusic acid found in asparagus, into other sulfur-containing compounds, such as methanethiol, the most prominent odorant identified in “asparagus pee.”
Interestingly, not everyone can detect the “asparagus pee.” A research study of almost 7,000 adults found that 40% could smell the odour, while 60% could not. When looking at possible genetic causes, the researchers found that the ability to detect the smell was linked to a specific DNA sequence that varied between different people. This means a single molecule change in the genes responsible for smell may be linked to the inability to smell asparagus odour in urine.
For more info on this check this out: https://theconversation.com/why-does-asparagus-make-some-peoples-pee-smell-but-not-others-48514