Hippurate: A Urine Marker of a Healthy, Diverse Gut Microbiome

Your gut microbes don’t just digest food — they produce molecules that circulate through your body and shape your health. This 2021 study, published in Gut, zeroed in on one of the most informative of those molecules: hippurate, a compound excreted in urine.

What the researchers did

The team measured 292 urinary metabolites in 271 middle-aged adults, then replicated their findings in 420 more people plus pairs of identical twins. Hippurate is made when gut bacteria break down dietary aromatic compounds (from fruits, vegetables, tea and coffee), after which the liver and kidneys finish the job. To test whether hippurate is merely a marker or actually does something, they also infused it into mice on a high-fat diet.

What they found

• Out of 292 metabolites, hippurate was the single one most strongly associated with gut microbial gene richness — a standard proxy for a diverse, healthy microbiome.
• Low hippurate tracked with insulin resistance, higher BMI, inflammation, fatty liver and Crohn’s disease.
• Strikingly, 61.1% of hippurate’s protective link to metabolic syndrome was explained by its connection to microbiome diversity.
• In mice, chronic hippurate infusion improved glucose tolerance by nearly 24% and boosted insulin secretion — evidence that hippurate is not just a bystander but a mediator of metabolic health.

Why it matters

This work cements urine as a non-invasive readout of gut health. A high level of this gut-derived molecule signals a diverse microbiome and lower metabolic risk; a low level flags the opposite. As the authors put it, hippurate is “the metabolite most significantly associated with microbial gene richness.” It is a clear demonstration that what your gut microbes make ends up measurable in your urine — and matters for your whole-body health.

“Increased Shannon diversity and the hippurate trend were associated with a reduced odds of having metabolic syndrome, with 61.1% of the hippurate effect… being mediated by the association between Shannon diversity and metabolic syndrome.”