Why Does Asparagus Make My Urine Have a Odor?

Ever wonder why your urine has a strange odor after eating asaragus? Well, a city guy did and sent in this question:

Question from Jay: This may be a strange question, but I have always wondered why my urine has a weird smell after eating asparagus. BTW – why don’t you have a section for guys?

Answer from Martha: No – that really is not a strange question. I don’t think you are the only person who has thought about it. Actually, there have been quite a few studies that have been done on the whole issue of asparagus and urine odor. The strange odor to urine that occurs after eating asparagus is due to various sulfur-containing degradation products, including various thiols, thioesters, and ammonia. These are some of the same compounds that gives skunks their offensive odor! 

Here is where the debate comes in:
– Some studies have shown that only about 40% of us have the gene that produces this odorous compound
– Other studies indicate we all produce it, but some of us can’t smell it.

The odor in urine can occur within 15-30 minutes after ingesting it. Those are sneaky little asparagus! I noticed one time I got a salad from the “tossed” type places. By mistake a little piece of asparagus must have fallen into my bowl (you know how hyper those salad guys can get with their salad thongs). Well, not to get graphic, but 15 minutes after eating the salad, I knew I must have eaten a piece of asparagus.

My last bit of advice Jay, the first time you cook for your girlfriend, you may want to avoid cooking a meal that contains asparagus! And yes, I will be starting a For City Guys Only category. Thanks for the idea.