Direct supplementation with Urolithin A overcomes limitations of dietary exposure and gut microbiome variability in healthy adults to achieve consistent levels across the population

Background Urolithin A (UA) is produced by gut microflora from foods rich in ellagitannins. UA has been shown to improve mitochondrial health preclinically and in humans. Not everyone has a microbiome capable of producing UA, making supplementation with UA an appealing strategy. Objective This is the first detailed investigation of the prevalence of UA producers in a healthy population and the ability of direct UA supplementation to overcome both microbiome and dietary variability. Dietary intake of a glass of pomegranate juice (PJ) was used to assess UA producer status (n = 100 participants) and to characterize differences in gut microbiome between UA producers from non-producers. Methods Subjects were randomized (1:1) to either PJ or a food product containing UA (500 mg). Prevalence of UA producers and non-producers were determined in the PJ group. Diet questionnaires and fecal samples were collected to compare differences between UA producers and non-producers along with plasma samples at different time points to assess levels of UA and its conjugates between the interventions. Results Only 12% of subjects had detectable levels of UA at baseline. Following PJ intake similar to 40% of the subjects converted significantly the precursor compounds into UA. UA producers were distinguished by a significantly higher gut microbiome diversity and ratio of Firmicutes to Bacteroides. Direct supplementation with UA significantly increased plasma levels and provided a >6-fold exposure to UA vs. PJ (p < 0.0001). Conclusions Differences in gut microbiome and diet that dictate natural exposure to UA can be overcome via direct dietary UA supplementation.

Automated summary

This study investigates the prevalence of UA producers in a healthy population and the effectiveness of direct UA supplementation in overcoming microbiome variability. Results show that 40% of subjects converted precursor compounds into UA after consuming pomegranate juice. UA producers were characterized by higher gut microbiome diversity and a specific bacteria ratio. Direct supplementation significantly increased plasma UA levels, providing a >6-fold exposure compared to PJ.