Ellagic acid metabolism by human gut microbiota: consistent observation of three urolithin phenotypes in intervention trials, independent of food source, age, and health status.
Level 4 - case-series / case-control
Pooled observational analysis of metabolic phenotypes across dietary intervention cohorts (letter format)
PubMed 24976365 · doi:10.1021/jf5024615
What was done
The authors analyzed urolithin production profiles in human volunteers across multiple intervention trials following the intake of ellagitannin and ellagic acid from diverse food sources (walnuts, other nuts, strawberries, raspberries, other berries, and pomegranates). They evaluated the distribution of urolithin production patterns across demographic variables (age, gender, body mass index) and health statuses (including metabolic syndrome and colorectal cancer).
What was found
Volunteers consistently segregated into three distinct metabolic phenotypes: - Phenotype A (produced only urolithin A conjugates): represented 25% to 80% of volunteers across trials. - Phenotype B (produced isourolithin A and/or urolithin B in addition to urolithin A): represented 10% to 50% of volunteers. - Phenotype 0 (no urolithins detected): represented 5% to 25% of volunteers. These phenotypes emerged independently of food source, age, gender, or BMI. Volunteers with chronic conditions linked to gut dysbiosis (metabolic syndrome or colorectal cancer) showed a higher percentage of Phenotype B.
Why it matters
This stratification explains why individuals experience divergent physiological responses to dietary ellagitannins and establishes urolithin metabotypes as potential biomarkers of gut microbiome composition.
Limits
The abstract is from a letter and does not report total participant numbers (n), specific trial designs, or exact statistical comparisons. Specific gut microbial taxa driving each metabotype were not detailed.
Cited by
- supports Approximately 50% of the human population lacks the gut bacteria required to synthesize urolithin A from diet.