What makes urine yellow? Maryland scientists make breakthrough discovery with health implications

BALTIMORE -- Have you ever wondered why urine is yellow? Turns out mankind hasn't known exactly why until recently, thanks to researchers in Maryland. 

A team of scientists at the University of Maryland and the National Institute of Health solved the mystery, according to a study published last week in the journal Nature Microbiology.   

The discovery is huge in the scientific community, researchers say, because their findings will also help them uncover other medical mysteries linked to illnesses.

Although UMD has it figured out, we hit the streets of Baltimore to hear your scientific theories.

"I feel like it depends on the amount of water, because the more water we drink it could turn out lighter," one passerby told WJZ's Nicky Zizaza. 

"I believe the pee is yellow because it means you are dehydrated," another said. "Mine is not yellow, its white, because I drink a lot of water."  

Brantley Hall, the lead author of the study and an assistant professor at UMD, says they have identified the enzyme bilirubin for giving urine its yellow hue. It's linked to red blood cells setting off a biological process that has, until now, eluded the scientific community.  

"If you have ever wondered why your urine is yellow, think of your microbes in your gut," Hall said. "We're definitely standing on the shoulders of giants. If some of these older scientists had the technology we had today, they probably would've found it."

Hall says the discovery will make way for medical breakthroughs like inflammatory bowel disease and jaundice

"One of the major findings of our studies is that this gene was often absent in newborn babies," he said. 

 Hall says the next step is human studies, specifically for premature infants with high jaundice rates.