Asparagus pee redux.

Hey, Matt:

Why does asparagus make my pee stink?

-- Anonymous, somewhere

In this land of climatic sameness, how does Matthew Alice know that spring has arrived? (1) Grandma Alice packs away her winter aprons in mothballs, (2) the asparagus-urine questions sprout from my mailbox. The Capistrano swallows have nothing on people with smelly pee each spring. We've discussed this before, we'll do it one more time. Then each of you tell ten friends; they tell ten of their friends; pretty soon everyone will know and they'll stop asking me. Proudly I can say, UCSD finally solved the smelly pee question in 1975, when a chemistry professor identified several S-methyl thioesters as the odorous culprits. Thioesters are formed when acids and sulfurous stuff interact. In humans, the interaction is controlled by a specific gene that not everyone has. Maybe a third of the population is lucky enough to stink when they eat asparagus. Got it? Great. Pass the Hollandaise.