Pomegranate Dietary Supplements in AUD and ALD

A large body of anecdotal evidence suggests beneficial effects for many botanical dietary supplements (BDS) on human health. The U.S. alone spent ~$7.5 billion on BDS in 2016, suggesting significant interest in the consumption of such products. Since ancient times, pomegranate has been known as a 'healing food', with numerous health benefits, including prevention of health risk factors for high blood pressure, arthritis, high cholesterol, oxidative stress, and hyperglycemia (1-4). Despite reported benefits from consumption of pomegranate dietary supplements (PDS), the overall outcomes of clinical trials were not uniform, and the results were inconclusive (5-7). However, gut microbial metabolites derived from polyphenolics of pomegranate have been shown to promote many beneficial activities, including anti-oxidative and anti-inflammatory activities (8- 12). Thus, the inter-individual variation in human gut microbiota compositions and their metabolic capacities may hamper the predicted PDS-mediated benefits. We postulate that harboring the specific gut microbiota responsible for metabolizing PDS into beneficial metabolites is critical to manifesting the complete benefits of PDS consumption. Recently, we reported one such microbial metabolite, 'urolithin A' (UroA), derived from ellagic acid-rich diets (e.g., pomegranate), significantly enhanced gut barrier function in addition to blocking unwarranted inflammation in colitis models (13) and protected from alcoholic liver disease (ALD) in mouse models (unpublished data). UroA is produced only in 40-50% of humans, who harbor the appropriate microbiota capable of converting consumed ellagic acid-rich diets (such as pomegranates, berries, and walnuts). UroA levels varied significantly among populations, to micromolar levels in some individuals. The direct correlations between UroA levels and human health/disease conditions are not yet available.

This project aims to determine an individual's ability to generate active gut microbial metabolites called urolithins upon consumption of pomegranate dietary supplements. We, and others, reported that urolithins are the major active metabolites that are responsible for the beneficial activities that are rendered from eating pomegranates, berries, or walnuts. However, the production of urolithins from the parent compound ellagic acid (EA) is dependent upon the presence of certain bacteria in the human gut. In this trial, we propose to investigate variations in gut microbiota and their capacity to metabolize pomegranate dietary supplements (PDS) into active urolithins. We will measure the levels of urolithins in blood as well as inflammatory cytokines in plasma samples upon consumption of PDS.