Ellagic Acid Metabolism by Human Gut Microbiota: Consistent Observation of Three Urolithin Phenotypes in Intervention Trials, Independent of Food Source, Age, and Health Status

bacchus otherFrancesco Tomás-Barberán and colleagues from CEBAS-CSIC(ES) have described three phenotypes for urolithin production, after intake of ellagitannin and ellagic acid. The proposed phenotypes could explain inter-individual variability in health benefits associated with these compounds and potential differences in the human gut microbiota. The authors go on to recommend stratification of study participants according to urotholin phenotypes in future dietary intervention trials.

Intakes of ellagitannins and ellagic acid are often under-estimated, despite the potential health benefits associated with regular consumption of polyphenol-rich foods. Ellagitannin and ellagic acid are transformed by the gut microbiota to produce urolithins, bioavailable metabolites that exert anti-inflammatory and anti-carcinogenic effects, and can reach high concentrations in both normal and tumour human colonic tissue.However, there is wide inter-individual variability in potential health effects that might be due to differences in urotholins production. Tomás-Barberán et al. identified three phenotypes according to individuals’ capacities to excrete urotholins, independent of food source or health status.

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  1. Phenotypic variation in urotholin excretion could indicate differences in potential health benefits or risk.
  2. Individuals can be grouped consistently as one of three phenotypes (A, B or 0), according to their capacity to excrete urolithins, independent of food source or health status.
  3. In 0-phenotype individuals, ellagic acid either remains un-metabolised or might be metabolised differently, leading to compounds other than urolithins.