Scientists Discover Thousands of Chemicals in Human Urine

Human urine is a surprisingly complex substance. But now, scientists have finally determined the chemical composition of human urine after more than seven years. They've identified the more than 3,000 chemicals or "metabolites" in the liquid, revealing a little bit more about the human body.

In order to actually piece together the ingredients of urine, the researchers used analytical chemistry techniques, including nuclear magnetic resonance spectroscopy, gas chromatography, mass spectrometry and liquid chromatography. This allowed them to systematically identify and quantify hundreds of compounds from a wide range of human urine samples.

That's not the only technique they employed, though. The scientists also used computer-based data mining techniques in order to examine more than 100 years of published scientific literature about human urine. This allowed them to add to their own body of research.

"Urine is an incredibly complex biofluid," said David Wishart, the senior scientist of the project, in a news release. "We had no idea there could be so many different compounds going into our toilets."

The fact that the researchers managed to find so many different compounds will have enormous implications for future research. In fact, scientists have used urine for years as a way to diagnose disease and ailments.

"Most medical textbooks only list 50 to 100 chemicals in urine, and most common clinical urine tests only measure six to seven compounds," said Wishart. "Expanding the list of known chemicals in urine by a factor of 30 and improving the technology so that we can detect hundreds of urine chemicals at a time could be a real game-changer for medical testing."

The findings could allow researchers to develop a whole new generation of fast, cheap and painless medical tests. In particular, urine-based diagnostic tests for colon cancer, prostate cancer, celiac disease and other diseases are already being developed or are about the enter the marketplace thanks to this work. Yet the findings aren't over.

"This is certainly not the final word on the chemical composition of urine," said Wishart. "As new techniques are developed and as more sensitive instruments are produced, I am sure that hundreds more urinary compounds will be identified."

The findings are published in the journal PLOS One.