We Unravel The Science Mysteries Of Asparagus Pee

"As Ben Franklin noted, some of you have 'the Power of changing, by slight means, the smell of another discharge ... our water. A few stems of asparagus eaten, shall give our urine a disagreeable odour.' Apparently this is so common a power that the 18th century French botanist Louis Lémery wrote that asparagus causes 'a filthy and disagreeable smell in the urine, as everybody knows.'"

"Everybody except me, anyway."

"I'd never heard of this particular side effect of asparagus until I was in my 20s, and I ate plenty of asparagus growing up. The difference between people like myself and people like Lémery lies somewhere among more than 800 different genes, according to a new study that searched for genetic differences between those who claim they can and those who claim they can't smell asparagus pee."

"The researchers asked nearly 7,000 participants if they could detect a distinct smell in their urine after eating asparagus. About 40 percent of them strongly agreed they could. The other 4,161 people (I imagine) were confused by the question. According to the study, published in BMJ on Tuesday, these people share some combination of at least 871 different genetic alterations that may blunt their ability to smell asparagus pee."