Coprolithins

Coprolithins are metabolites produced by the human gut microbiota during the digestion of ellagitannins and ellagic acid, polyphenols found in foods such as pomegranates, berries, walnuts, and red wines. In nutrition and metabolomics, the term refers to microbial transformation products that are subsequently excreted in urine and feces.

Upon ingestion, ellagitannins reach the colon where gut bacteria metabolize them into a family of compounds collectively known as coprolithins. These include derivatives related to urolithins, which can undergo further conjugation to form glucuronides or sulfates detectable in biological fluids.

Coprolithin profiles vary between individuals because gut microbiota composition determines which transformations predominate. Thus, people exhibit different coprolithin metabotypes, influencing bioavailability and biological activity. They are studied as biomarkers of ellagitannin intake and as potential mediators of health effects linked to ellagitannin-rich diets.

Current research investigates whether coprolithins contribute to anti-inflammatory, antioxidant, or mitochondrial-related benefits attributed to ellagitannins. Evidence is preliminary and inconsistent; more work is needed to clarify mechanisms, dose-response relationships, and clinical relevance. Note that the term coprolithin is distinct from coprolites, the fossilized feces found in the paleontological record.