What your urine says about your health

A few years ago, scientists raised the flag about a potentially troubling source of water pollution: American urine.

Although modern diets push protein, Americans actually eat About 40% more Of the recommended amount daily. One side effect of excess protein is increased nitrogen in the urine. When this powerful cocktail reaches the environment, it can cause toxic algae blooms, disrupt ecosystems, and make drinking water unsafe, says Maya Almers, a biogeochemist at Yale University who co-authored this article. Paper 2022 On the problem. She and her colleagues calculate that, thanks to excessive protein intake, more than 600,000 tons of excess nitrogen is excreted in Americans’ urine each year.

This is just one example of the many surprising insights urine can reveal about our health and habits. “If you consume alcohol, there are distinct molecules in your urine,” says Joshua Kuhn, a professor of chemistry at the University of Wisconsin-Madison. “If you have coffee, we can see the signature on it.” Some types of brain tumors even leave visible traces in urine before they are detected by other means, says David Wishart, a professor at the University of Alberta who has pioneered the study of molecules in urine and maintains Database More than 3,000 molecules were discovered in human urine. Advances in basic research reveal that “there is gold,” he muses, “in that golden-colored liquid.”

What can urine tell us?

Many people have urinated into a plastic cup at the doctor’s office or onto a stick at home. One standard test looks for sugar in the urine to diagnose diabetes. Other flags: human chorionic gonadotropin, which is a sign of pregnancy.

These tests work because urine contains metabolites: waste products from the daily work of breaking down and building new molecules. Just as litter from a household can reveal, for example, whether residents are vegetarians, metabolites reveal what’s going on inside the body. “If there’s something wrong going on in the body, it tends to get concentrated in the urine,” says Wishart.

Read more: Am I urinating a lot?

Wishart and colleagues found A panel of 69 metabolites in people’s urine can predict who has pre-cancerous colon polyps. In 2020 he and his collaborators published A test for 149 different metabolites in urine, with the goal of having others in the research community use it to study urine and perhaps create new laboratory tests.

Urine is not useful for everything. Urine isn’t as good a predictor as blood when it comes to many tissues, including muscle and heart tissue, says Michael Snyder, a genomics scientist at Stanford University who has pioneered the use of long-term personal monitoring of health.

However, it can provide particularly detailed information about what people are eating. “It’s a good window into diet and supplements,” Snyder says. In fact, in One study 2019 From Kuhn’s lab Aiming to see if urine could be used to monitor health in real time, he and his colleagues collected all the urine produced by two volunteers for 10 days. They were able to see evidence of exercise, traces of certain nutrients, and even acetaminophen taken the night before, essentially a record of these people’s daily lives.

Tomorrow’s toilet

One of the main benefits of urine is that it is readily available, and is a more convenient way to monitor health than a daily blood draw, for example. “The restroom is really the place to be,” Kuhn says. He and his colleagues have continued to explore sensors in toilets that could regularly track metabolites in urine, aiding in precision medicine. Such sensors could alert doctors if a rare molecule suddenly spikes in someone’s urine, monitor a person’s diet in detail, and provide insight into how drugs are metabolized, for example. “We need to know how to make measurements in the toilet,” Kuhn says. “This is ideal.”