So a mystery for more than 100 years, researchers finally reveal the cause of yellow urine

Have you ever wondered why the color of urine that comes out of the body is yellow? Whether it’s dark yellow or light colored. Now you can sleep in peace, because your curiosity about the causes of yellow urine has been answered.

READ ALSO: What Color is Your Urine? Come on, get to know what it means medically!

Researcher’s Findings on the Causes of Yellow Urine

The content of urine or urine is a mixture of water, electrolytes and toxins or body waste filtered by the kidneys. Why normal urine tends to be yellow was actually revealed by a team of scientists through research in 1868, namely the presence of urobilin. However, where urobilin comes from and how it is processed remained a mystery for more than a century, until it was finally revealed recently.

Yes, a team of researchers from the University of Maryland and the National Institutes of Health in the United States, identified the microbial enzyme that gives the urine excreted by the body a yellow color. This enzyme is known as bilirubin reductase (BilR) which is part of the gut microbiome.

“The discovery of this enzyme finally reveals the mystery behind the yellow color of urine,” said Brantley Hall, lead researcher on the study. These findings were published in the Nature Microbiology Journal on January 3 2024.

Understand What Bilirubin Is

Bilirubin is a byproduct of red blood cells which fades in color after six months of age. At moderate levels, bilirubin functions as an antioxidant so the potential health benefits are very large. On the other hand, if the serum bilirubin concentration in the body increases, this can actually be toxic to the body. Namely, it can cause jaundice and cause nerve damage.

Therefore, maintaining the metabolism of bilirubin production and gut microbiota is very important. One effort is to reduce or reduce it by removing it from the body.

Together with other organic molecules in bile such as cholesterol and bile acids, bilirubin is then secreted into the intestines to be excreted or reabsorbed by the body.

Relation to Causing Yellow Urine

Returning to BilR, in the process of reducing bilirubin – before it is excreted from the body – then BilR converts bilirubin into urobilinogen. “Urobilinogen then spontaneously breaks down into a molecule called urobilin, which is responsible for the yellow color we are all familiar with,” explains Hall.

Urobilin has long been linked to causing urine to have a yellow color. However, how urobilin is formed has only now been revealed by a research team after more than a century.

Regarding the existence of BilR, the results of the human intestinal metagenome analysis carried out by the research team revealed that BilR is generally present in the intestines of healthy adults. However, the prevalence of the gene is much lower in patients with inflammatory bowel disease (IBD) and in infants, especially during the first few months of life.

This is a strong reason why newborn babies are very susceptible to jaundice. Then BilR only appears when the baby is one year old.

This Discovery, What are the Benefits for Health?

Apart from answering the mystery of why urine is yellow, the finding of the BilR enzyme further strengthens the evidence for the role of intestinal microorganisms in bilirubin metabolism. Researchers also hypothesize that the absence of bilirubin reductase can cause jaundice in babies and the formation of gallstones.

The discovery of the BilR enzyme is also considered an entry point to investigate how the presence of bacteria in the intestine has a major impact on the circulation of bilirubin levels, including the health problems it can cause, namely jaundice.

READ ALSO: Moms Must Know, These Are Normal Bilirubin Levels in Newborn Babies

Now you understand why normal urine color tends to be yellow, it turns out there is a long process behind it. However, it is hoped that this research will not only reveal the color of urine, it is hoped that it will further reveal the health impacts it causes.

Stay healthy, if you have complaints that the color of your urine is not yellow, immediately consult the relevant doctor, because the color of urine can actually reveal the health condition of your body. 

Regular consultations with our doctor partners. Download the Good Doctor application now, click this link , OK! Now, all health information is at your fingertips!

References

1.College of Computer, Mathematical, & Natural Sciences, accessed January 17 2024. What Makes Urine Yellow? UMD Scientists Discover the Enzyme Responsible.

2.Nature.com, accessed January 17 2024. BilR is a gut microbial enzyme that reduces bilirubin to urobilinogen.

3.New York Post, accessed January 17, 2024. The over 150-year mystery of why urine is yellow has finally been cracked: study.

4.Today Umd, accessed January 17 2024. Colorful Mystery Solved: Scientists Discover Enzyme That Makes Urine Yellow.