Does Asparagus Make Your Pee Smell?

Asparagus is not only a healthy vegetable to eat, but also one that smells quite good. Its unique aroma, however, has led many to believe that asparagus makes their pee smell. However, new research suggests that this might not be true. A recent study found that while asparagus does smell very good, its scent is caused by an ingredient called Aspargusic acid. This compound can only be found in certain plants, and it is thought that the human body may not be able to recognize it as a flavor.


There is a lot of speculation about what produces the asparagus pee smell. Some suggest the sulfurous compound methanethiol. Others claim that it is a combination of two compounds.

Methanethiol is the prime suspect. It is a sulfurous byproduct of asparagusic acid. It is also a common additive in natural gas. In fact, the Texas legislature passed a law mandating methanethiol in natural gas.

Another candidate is dimethyl sulfone. Dimethyl sulfone is practically odorless, but it is also a low vapor pressure product. When voided from the body, the resulting gas can be quite foul-smelling.

Researchers have attempted to identify the chemical that produces the asparagus pee smell. Several different studies have been carried out. One is by Pelchat. They collected urine from four hundred and eighty volunteers. Then they analyzed the samples.

Unlike previous studies, these researchers did not test whether the asparagus pee smell is due to a single chemical. Instead, they used a chemical test to determine whether the odor was present. Their results showed that 63 percent of the participants reported the asparagus pee smell.

However, the authors did not provide any details on the chemical test or any method for measuring the odor. Nevertheless, the scientists did report that methanethiol was evident.

Researchers also looked at a genetic component of the asparagus pee smell. This genetic variant was a variant near a gene called OR2M7. This gene responds to geraniol, a compound that is also present in asparagus. According to the authors, if you have this mutation, you have a slightly decreased ability to detect asparagus metabolites in your urine.

A recent study by 23andMe found a tiniest stretch of DNA that was different between people who notice the asparagus pee smell and those who don’t. Researchers are still trying to figure out how this small difference influences the ability to detect asparagus.

The asparagus pee smell is only noticeable for the first few hours after eating it. After that, the effect fades away. Moreover, it is not a universal experience.

Aspargusic acid

Asparagus pee is the pungent odor that some people smell in their pee. This odor is often compared to rotten eggs or skunk spray. It is not a medical term, but the odor is attributed to asparagusic acid, which is found almost exclusively in asparagus.

The odor may be caused by a number of factors, including genetic mutations in the human olfactory system. There are many genes that regulate the function of the olfactory receptors. These genes affect the chemical components that humans perceive and can be manipulated to change the way we smell.

One of the most interesting things about the smell of asparagus pee is that it is not universal. Different people have different sulfur volatile profiles, so the skunk smell may be the result of a combination of factors.

A study in 2010 gathered samples of urine from a group of individuals with different levels of ability to detect the asparagus pee odor. They found eight71 gene variations that were strongly associated with the inability to smell asparagus pee.

Asparagus is a spring vegetable packed with antioxidants, vitamins and minerals. However, it is known to cause urine to stink, and a number of studies have been conducted to determine the exact causes.

Asparagusic acid is one of the chemicals that are thought to make urine smell. It is an organosulfur compound that is not usually found in other vegetables. In fact, it is metabolized into sulfur byproducts that may be released into the toilet.

Sulfur-containing compounds in asparagus and other foods can also be a problem, and can irritate the urinary tract. Moreover, it can taint the urine with acid. So, it is best to avoid asparagus when you are prone to urinary tract infections.

Another study tested asparagusic acid in urine. Researchers discovered that it metabolized into a chemical compound that is known to produce the odor, which was a laudable feat. Other compounds have been associated with smelly urine, but asparagusic acid is the only one that has been shown to actually make it.

Genetic variations in olfactory receptors

Asparagus anosmia is a condition in which a person is unable to detect the odor of asparagus after eating it. Scientists have not determined why some people are able to smell the odor while others are not. However, a number of genetic variants have been linked to this condition.

Anosmia is associated with a number of single nucleotide polymorphisms (SNPs). These variants are often found in the coding regions of olfactory receptor genes. They are believed to affect olfactory cognition and can affect the activity of olfactory receptors.

Studies have been conducted to find the genetic factors involved in asparagus anosmia. One study identified 871 DNA sequence variants. Some of these variants were associated with the ability to smell asparagus metabolites in urine.

The study was conducted by an international team of researchers. A large peak of 871 SNPs represented a 0.46 Mb region on chromosome 1. This large peak was split into two subregions by a recombination hotspot.

In the first study, 38 adult male and female subjects were evaluated. Six percent of the participants did not produce an asparagus odor, and eight percent of the participants did not produce any odor. Among the people that did not produce a odor, three SNPs were found.

Another study looked at the relationship between the inability to produce an asparagus odor and genetic variants. The researchers found that a single allele (A) was strongly associated with the ability to smell the odor.

Women were more likely than men to report that they were unable to smell the odor. Researchers also found that a woman’s position when urinating may affect her ability to notice unusual odors.

A group of researchers analyzed the genetic variation in the olfactory receptor genes that affect an individual’s ability to smell asparagus metabolites in their urine. Their results showed that the odor of methanethiol, the main odorant of asparagus, was highly dependent on DNA variants. Most of these SNPs were located in the olfactory receptor 2 gene family. There are four volatile compounds in asparagus that are studied for their association with odor perception.

The perception hypothesis

The perception hypothesis of asparagus making your pee smell is a scientific theory that suggests that gene variants make some people incapable of detecting the smell of asparagus pee in their urine. According to this theory, a small stretch of DNA is different in those people who can detect the smell and those who cannot.

However, this hypothesis is not entirely supported. It has been known for a long time that some people do not smell the odor of asparagus. As a result, some scientists believe that these people may not produce the metabolites that are believed to make the asparagus smell.

Researchers have tried to figure out what compounds are responsible for the odor in the urine of asparagus eaters. They have found a number of sulfur compounds, including dimethyl sulfide and methanethiol. These sulfur compounds are thought to be secreted in the urine of asparagus.

While the researchers discovered a gene that controls the production of these sulfurous compounds, it is unclear how these compounds are perceived by humans. Aside from being unpalatable, these compounds are very volatile, and they evaporate immediately after being excreted. This means that they would be lost during cooking, especially in methanol.

Other researchers have tried to study the genetics behind the asparagus pee smell. Penrose (1957) and Allison and McWhirter (1996) reported that a single variant in two genes controlled the amount of methanethiol in the urine of asparagus eaters. Their results showed that 46 out of 115 subjects produced methanethiol in their urine. But, they did not specify the chemical tests that were used to determine methanethiol.

Another group of researchers, Waring et al., studied odorous components in urine before and after eating asparagus. They concluded that the odor was caused by the presence of sulfur compounds.

Although scientists have discovered several genetic and odorant factors that might help explain how some people perceive the odor of asparagus, it is still unclear how the compounds are metabolized and excreted. Further research is needed to find out more about the chemical structure and molecular mechanisms that govern the way that we detect odor.

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