(Jacob Bruns, Headline USA) Researchers have discovered the cause of yellow urine, publishing their findings in the journal, Nature Microbiology, CBS News reported.
After decades of research, scientists finally concluded that, hydration levels aside, the color of urine is connected to the prevalence of degraded red blood cells.
“It’s remarkable that an everyday biological phenomenon went unexplained for so long, and our team is excited to be able to explain it,” Brantley Hall, an assistant professor in the University of Maryland’s Department of Cell Biology and Molecular Genetics, wrote in a statement.
The decaying of red blood cells—a natural process which takes place in the liver—produces an orange pigment, bilirubin, which migrates into the gut and is excreted via urine.
“Gut microbes encode the enzyme bilirubin reductase that converts bilirubin into a colorless byproduct called urobilinogen,” Hall, the lead author of the study, noted.
“Urobilinogen then spontaneously degrades into a molecule called urobilin, which is responsible for the yellow color we are all familiar with.”
According to National Institutes of Health investigator Xiaofang Jiang, the breakthrough will likely have a much broader effect than simply providing evidence of differing urine colors.
In light of the new research, “we can start investigating how the bacteria in our gut impact circulating bilirubin levels and related health conditions like jaundice,” he noted.
“This discovery lays the foundation for understanding the gut-liver axis.”
In short, the urine of a healthy, hydrated person’s urine should be a light yellow color. Darker urine is a sign of dehydration, and other colors could result from a dietary change, or indicate a larger problem altogether.
