The Asparagus Pee Phenomenon Explained

Dating as far back as the Ancient Romans, asparagus has been cultivated for medicinal and nutritional reasons. Loaded with antioxidants and anti-inflammatory phytonutrients, asparagus is known to reduce the risk of diabetes, heart disease, and certain cancers, such as colon cancer. The aspartic acid found in asparagus also helps to neutralize excess ammonia in the body, which can lead to sexual disinterest, making this vegetable a powerful aphrodisiac.

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As long as people have been consuming this vegetable, they've also been discussing its undesirable side effects. We're talking about that strange, unpleasant odor you smell in your urine after eating asparagus. In 1731, Scottish mathematician and physician John Arbuthnot wrote that, "Asparagus affects the urine with a foetid smell." French novelist Marcel Proust later remarked on the vegetable's power to "transform [his] chamber-pot into a flask of perfume." Thankfully, for those of us living in the twenty-first century, modern science has shed light on this bizarre phenomenon.

Asparagus contains a chemical called asparagusic acid. When the body digests the vegetable, this acid is broken down into several sulfur-containing compounds. As with other sulfur-containing substances, such as skunk spray and rotten eggs, these compounds produce a powerful, unpleasant odor. These molecules are also volatile, meaning they can vaporize and enter a gaseous state at room temperature. This allows the odor to travel from your urine, into the air, and up to your nose.

For some people, the scent can be detected as soon as 15 minutes after consuming asparagus. Others simply don't smell anything different after they eat the vegetable. Scientists have been trying to pinpoint the reason behind this divide decades. A study conducted in the 1980s with participants from France and Israel found that everyone produces the aroma, but some are unable to smell it. A more recent study conducted in 2010 found that there are differences between both production and detection of the scent among individuals.

Regardless of what camp you fall into, rest assured that this strange scent is completely innocuous. Simply hold your nose and continuing reaping the numerous benefits of this delicious and nutritious vegetable.

The accompanying slideshow is provided by fellow Daily Meal editorial staff member Anne Dolce.