Scientists Explain Why Urine is Yellow
We're told to pay attention to changes in the color of our urine, because loss of its normal, yellow color can be a sign of a medical problem – but why exactly does urine turn yellow in the first place?
Turns out, scientists didn't know the exact answer to this question until recently. Now, researchers have discovered that the golden color of urine is caused by an enzyme called bilirubin reductase, which is produced by bacteria in the intestine. Scientists reported their findings in a new study published Wednesday (Jan. 3) in the journal Nature Microbiology.
Scientists already knew that the yellow color of urine depends on how the body disposes of old blood cells. When red blood cells reach the end of their life cycle – usually after about 120 days – they are destroyed in the liver. ...