Most people detect a distinct sulfurous odor in their urine shortly after eating asparagus. The smell of their urine within a half-hour of consuming asparagus has been compared to rotten eggs, cabbage or wet earth. Why? Some scientists believe that certain people have a gene which produces a digestive enzyme that releases a chemical compound called methyl mercaptan, the same chemical that skunks release in defending themselves. It would be interesting to know what this all means from an evolutionary point of view, but we don’t.
You may not, or you may know someone who claims to not, experience the odorific pee phenomenon. Science has never explained, until now, whether those claiming not to experience the smell really don’t produce the odor or whether they just can’t smell it.
A new study published online in the journal Chemical Senses, says the answer is that some people don’t produce the odor but others do produce it but can’t smell it.
The study conducted at the Monell Chemical Senses Center, an independent nonprofit basic research institute based in Philadelphia, tested the urine of 38 subjects before and after eating roasted asparagus, and before and after eating bread. Researchers determined that approximately eight percent of people tested did not produce the odorous substance, while six percent were unable to smell the odor. One person both did not produce the odor and was unable to smell it.
How does that happen? By looking at DNA samples from each subject, researchers discovered that the inability to smell the asparagus odor was linked to a genetic variation in olfactory receptors. That change in genes can affect a person’s ability to smell certain sulfurous compounds including mercaptan, which is the chemical used to add odor to natural gas pipelines so that people are able to detect gas leaks.
You will want to experiment on yourself and your family to find out whether you are in the asparagus fumes-free minority and whether your olfactory receptors are working. But there are lots of other good reasons to enjoy asparagus.
Asparagus has been used as a natural remedy in Europe and Asia for centuries and is thought to ward off the signs of aging. A member of the Lily family, asparagus is both a delicacy and an excellent source of vitamins A, E and C and thiamin. It has no fat or cholesterol, is high in fiber and a good source of potassium. Promising research at Rutgers University is studying the effect of 2 phytochemicals abundant in asparagus that are believed to inhibit the growth of cancer cells in colon cancer and leukemia.
If you are thinking of getting pregnant or in the early stages of pregnancy, asparagus is an essential addition to your diet because it is a rich source of folate, a B-vitamin necessary for healthy cell division and DNA synthesis, and instrumental in preventing birth defects. Even if you are not in the child bearing game, a lack of folate has been linked to heart attack, stroke, osteoporosis and Alzheimer’s disease. Moreover, if you drink alcohol, you are more likely to be deficient in folate.
Here is a quick, simple and delicious recipe to help you conduct your own smelly urine experiment.
Lemon Asparagus with Avocado
- 1 bunch asparagus
- 1 tablespoon extra virgin olive oil
- Juice of one lemon
- 1 teaspoon grated lemon zest
- 1 Avocado, diced
- Celtic sea salt and fresh ground pepper to taste
Wash asparagus and trim bottoms. Cut into 1- to 2-inch pieces on the diagonal.
Add asparagus to a pot of boiling water, reduce heat to simmer and cook for 2 minutes. Drain.
In a bowl, combine oil, lemon juice, lemon zest, salt and pepper and toss with asparagus.
Add diced avocado and toss gently.