We recently had friends over for dinner and served asparagus, one of our favorite springtime vegetables. After a few drinks and a few trips to the bathroom, someone mentioned in passing, “the asparagus effect”. My husband and I chuckled, however a few of our other guests did not get the joke. According to statistics, only about half of you will know what I am talking about. Asparagus contains sulfur compounds that, when broken down in our urine, give off a smell similar to cooked cabbage. It appears that only about 46% of people experience this smell after eating asparagus. There has surely been debate among friends who insist the “non-smellers” are simply too polite to admit the odour. There appears to be a scientific explanation for this mystery. Believe it or not, the topic of “odorous asparagus urine” has been the topic of much research and debate since 1891. It was originally thought that those who could not smell the odour were simply not producing the sulfur compounds. It was later shown that some people produced the sulfur compounds but were simply not able to smell them. We now know that the ability to produce and smell the odorous asparagus compounds is genetically determined. People are divided into "producers or non-producers" and “smellers or non-smellers”. It is controlled by a dominant gene which means if both your parents experience “the asparagus effect” you will most likely get it as well. You may or may not choose to bring it up at your next family function. There are no known health benefits associated with the sulfurous “asparagus effect”, it is purely a bit of metabolic trivia for those interested in the idiosyncrasies of the human body. That is not to say there are no health benefits to eating asparagus. As a green vegetable it provides a rich source of potassium, folate and B vitamins. It contains less than 4 calories per spear and provides a good source of fibre at a meal. Another nice feature of this vegetable is the ease of preparation. There is no slicing or scrubbing required. Simply rinse well and chop off the tough ends. You can steam them for a few minutes on the stove or cook them briefly in the microwave with a bit of water. My favorite way to serve asparagus is brushed lightly with olive oil, sprinkled with coarse salt and barbequed on the grill until just tender. It's always worth cooking up extra to use the next day in an omelet or wrapped in deli meat as a snack. Asparagus is truly a versatile and healthful vegetable with a little surprise, courtesy of Mother Nature, to remind us of the countless wonders going on inside the human body.
More information on asparagus and food idiosyncracies:
http://dmd.aspetjournals.org/cgi/content/full/29/4/539
Heidi Smith is a Registered Dietitian from the Health and Performance Centre. She is the author of the book “Nutrition for the Long Run - A nutrition handbook for runners, walkers and active individuals”. Her column runs every Thursday