Several years back, researchers identified American urine as a concerning potential contributor to water contamination.

Despite the prevalence of high-protein diets, Americans typically consume more protein than advised daily. A byproduct of this surplus protein is increased nitrogen in urine. When this concentrated mixture enters the environment, it can lead to harmful algal blooms, upset ecological balance, and render potable water unsafe, according to Maya Almaraz, a Yale University biogeochemist and co-author of research on this issue. Her team estimated that over 600,000 tons of surplus nitrogen are excreted annually in American urine due to excessive protein intake.

This is merely one instance of the numerous unexpected revelations that urine can offer regarding our well-being and routines. Joshua Coon, a chemistry professor at the University of Wisconsin-Madison, notes, “Should you drink alcohol, distinctive molecules appear in your urine.” He adds, “If you consume coffee, we can detect its characteristic markers.” Even specific types of brain tumors leave indicative signs in urine, potentially before detection through other methods, explains David Wishart, a University of Alberta professor who has spearheaded molecular urine research and curates a database of over 3,000 molecules found in human urine. Fundamental research breakthroughs are showing that, as he muses, “there’s treasure in that golden fluid.”

What insights can urine provide?

Many individuals have provided urine samples in a cup at a medical clinic or used a test strip at home. A common test detects sugar in urine for diabetes diagnosis, while another identifies human chorionic gonadotropin, an indicator of pregnancy.

demonstrated that a group of 69 metabolites found in human urine could forecast which individuals possessed pre-cancerous colon polyps. In 2020, he and his colleagues introduced a test for 149 distinct metabolites in urine, intending for the broader research community to utilize it for urine analysis and the potential development of novel laboratory assessments.

Urine does not serve every diagnostic purpose. Michael Snyder, a Stanford genomicist renowned for his pioneering work in continuous personal health monitoring, notes that urine is less effective than blood as an indicator for various tissues, such as muscle and heart tissue.

Nevertheless, it can yield remarkably specific data concerning what individuals consume. Snyder comments, “It provides an excellent insight into diet and supplements.” In fact, during research from Coon’s laboratory exploring the potential of urine for continuous health tracking, he and his team gathered all urine output from two participants over 10 days. They successfully detected indications of physical activity, remnants of specific foods, and even acetaminophen consumed the previous evening—effectively creating a diary of these individuals’ daily routines.

Future toilet technology

A key advantage of urine is its accessibility, offering a more practical method for health monitoring compared to, for example, daily blood samples. Coon asserts, “The toilet is truly the optimal location.” He and his team have persisted in developing toilet-integrated sensors capable of consistently tracking metabolites in urine, thereby supporting precision medicine. These sensors could notify physicians if a typically rare molecule in someone’s urine suddenly surges, meticulously track an individual’s dietary intake, and reveal how they process medications, among other functions. Coon concludes, “We must determine how to conduct measurements in the toilet. That represents the ultimate goal.”

Almaraz possesses extensive knowledge of what is entering American toilets and is therefore dedicated to instigating change. Her observations indicate that individuals frequently resist the notion that they do not require additional protein, resulting in the ongoing release of excessive nitrogen into the environment. Consequently, she aims to educate people about the broader impacts of seemingly private dietary decisions and to highlight that urine can become hazardous waste.

“Diets are adaptable. They are constantly evolving,” she states. “My hope is that we can modify them for improved outcomes.”