You may not be able to fudge the truth when your doctor or dietitian asks about your diet for much longer. Urine tests are being developed that can offer a profile of the health of your diet. They may be able to produce a urine “fingerprint” that could lead to your receiving advice on healthy eating tailored to your biological make-up. Two new studies in Nature Food explain it all.

As your body breaks down the various foods you eat, small molecules called metabolites are created. These show up in your body fluids, so testing your urine can be an actual gauge of the quality of your diet. Diet is a key contributor to health and disease, but it is difficult to measure since it relies on a person’s ability to remember what they ate and how much they ate. Urine tests could provide much more accurate information.

Metabolites reflecting alcohol intake, citrus fruits, fructose, glucose and vitamin C, as well as those associated with eating red meat, were found in urine.

Researchers at Imperial College London, Northwestern University, University of Illinois, and Murdoch University analyzed urine samples from nearly 1,900 people in the U.S. in one study, measuring levels of 46 different metabolites in an effort to establish a link between metabolites found in urine and the quality of a person’s diet.

The team found 46 metabolites in urine that were associated with the types of foods or nutrients in a person’s diet. Metabolites reflecting alcohol intake, citrus fruits, fructose, glucose and vitamin C were identified, as well as those associated with eating red meat, other meats and nutrients like calcium. Other metabolites linked with obesity and high blood pressure were also detected.

“Through careful measurement of people's diets and collection of their urine excreted over two 24-hour periods we were able to establish links between dietary inputs and urinary output of metabolites that may help improve understanding of how our diets affect health,” explained Paul Elliott, Imperial College London, in a statement. “Healthful diets have a different pattern of metabolites in the urine than those associated with worse health outcomes.”

A five-minute test was developed as part of another study by the researchers at Imperial in collaboration with Newcastle University, Aberystwyth University and Murdoch University. It showed that the combination of metabolites in urine varies from one person to another, creating a “urine fingerprint.” Even among people eating the same diet, the metabolites found in their urine varied.

This “fingerprint” could give health professionals such as a registered dietitian nutritionist (RDN) more precise information on the quality of a person’s diet.

The next step is to examine how a person’s urine fingerprint may be connected to their risk of developing chronic health conditions and how a person’s body processes and uses food at the molecular level. Such information opens the door to providing “precision nutrition” advice tailored specifically to their body's biochemistry.