Urolithin A (UA) is a compound formed in our gut when consuming certain food types. UA is a metabolite derived from ellagitannins, a polyphenol found in various fruits and nuts.
Our bodies use Urolithin A for maintaining cellular health, which in turn supports various health functions [1].
This is important because, as we age, our body's ability to maintain efficient cellular function diminishes. We'll look closer at Urolithin A-rich foods and why supplementing a well-rounded diet with Urolithin A may be the key to maintaining your health goals as you age.
Where Does Urolithin A Come From?
Giving you a list of foods with Urolithin A isn't accurate because Urolithin A isn't directly found in foods.
Instead, it forms when our gut bacteria metabolize ellagitannins from certain foods. The ability to produce Urolithin A from foods can vary from person to person, depending on their unique gut microbiota (gut bacteria) composition [2].
The body forms Urolithin A through a complex process involving gut microbiota. Here's a simplified overview of how it happens:
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Eating Ellagitannin-Rich Foods: Consuming foods rich in ellagitannins, such as pomegranates, berries, and nuts.
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Initial Breakdown: Ellagitannins are hydrolyzed into ellagic acid in the human gut.
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Microbial Metabolism: Specific gut bacteria then metabolize ellagic acid into Urolithin A. Not all gut bacteria can do this, and the efficiency of this process varies among individuals based on their gut health and genetics.
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Absorption and Circulation: Once formed, Urolithin A is absorbed into the bloodstream, where it circulates.
Foods High In Urolithin A Precursors
Since Urolithin A isn't directly found in foods, we can ingest more of its precursors — ellagic acids and ellagitannins to reap its potential health benefits.
| Food | Description | Ellagic Acid/Ellagitannins per Serving |
|---|---|---|
| Pomegranates/ Pomegranate Juice/ Pomegranate Extract | Rich in antioxidants (punicalagins) and high in ellagic acid and ellagitannis. | 250–900 mg (typical in pomegranate extract) [3] |
| Walnuts | High in omega-3 fatty acids and ellagic acid. | 750 mg/100g ellagic acid [4] |
| Raspberries | Red raspberries are known for having some of the highest levels of ellagic acid. | 65 mg/100g ellagic acid [4] |
| Strawberries | Contains ellagic acid in leaves, seeds, and fruit pulp. | 22.3 mg/100g ellagic acid [4] |
| Almonds | Contains hydrolyzable tannins, including ellagic acid. | 54.7 mg/100g ellagic acid [5]. |
Due to factors like variety, cultivation conditions, and processing methods, it's hard to determine precisely how much ellagic acid or ellagitannins are present in each serving of these foods.
Urolithin A vs. Pomegranates
While pomegranates are a natural source of Urolithin A precursors, supplements in our pure Urolithin A capsules provide a more direct and potent form of Urolithin A with 700 mg per serving.
For example, one serving of pomegranate juice (8 fl. oz) may contain 570 mg of ellagic acid — but no detectable Urolithin A [7]. It's up to the human gut microbiota to convert those compounds into usable Urolithin A.
Urolithin A is a metabolite produced in the gut, and its formation relies upon the microbiota's ability to metabolize ellagitannins. This means that the 570 mg of ellagic acid doesn't necessarily equate to 700 mg of Urolithin A
While pomegranates are an excellent natural source of these precursors, the actual conversion to Urolithin A can be inconsistent due to individual variations in gut microbiota.
Urolithin A supplements provide a more direct and consistent source of this compound.
They bypass the variability of gut microbiota conversion, ensuring a reliable dosage of Urolithin A.
| Urolithin A Supplements | Pomegranates (Fruit, Juice, Extracts) |
|---|---|
Pros:
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Pros:
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Where Do Urolithin A Supplements Come From?
Urolithin A supplements are typically derived from precursors (ellagic acid and ellagitannins) found in pomegranate extract and synthesized in a lab to get pure Urolithin A.
This synthetic process ensures a consistent and potent form of Urolithin A, which is not dependent on the variability of individual gut microbiota for conversion.
So, while the precursors for Urolithin A originate from natural sources like pomegranates, Urolithin A in supplements is typically produced synthetically to achieve the desired purity and concentration.
Urolithin A Side Effects
Urolithin A is generally safe and non-toxic. Safety studies in elderly humans indicated it was well-tolerated as an oral supplement [8]. Furthermore, the FDA has listed Urolthin A as safe for food or dietary supplements within a specific range.
Even with that said, if you take too much Urolithin A, you could have gastrointestinal discomfort and headaches, so you don't want to exceed the recommended dosages outlined on your supplements.
Foods & Urolithin A Sources
We've clarified a common misconception regarding Urolithin A and its sources. It's important to understand that Urolithin A isn't found in foods. Instead, foods like pomegranates, walnuts, and various berries provide precursors to Urolithin A, such as ellagic acids and ellagitannins.
The actual production of Urolithin A occurs within the gut, where the gut microbiota transforms these precursors into Urolithin A. Consequently, supplementing with pure Urolithin A bypasses this variability, offering a more direct and potentially more effective approach to harnessing its benefits, particularly for specific health goals aligned with Urolithin A's properties.
Resources:
- Del Rio, D., Costa, L. G., Lean, M. E. J., & Crozier, A. (2010). Polyphenols and health: what compounds are involved? Nutrition, Metabolism and Cardiovascular Diseases, 20(1), 1-6.
- Singh, A., D’Amico, D., Andreux, P. A., Dunngalvin, G., Kern, T., Blanco-Bose, W., ... & Rinsch, C. (2022). Direct supplementation with Urolithin A overcomes limitations of dietary exposure and gut microbiome variability in healthy adults to achieve consistent levels across the population. European journal of clinical nutrition, 76(2), 297-308.
- Nuñez-Sánchez, M. A., González-Sarrías, A., García-Villalba, R., Monedero-Saiz, T., García-Talavera, N. V., Gómez-Sánchez, M. B., ... & García-Conesa, M. T. (2017). Gene expression changes in colon tissues from colorectal cancer patients following the intake of an ellagitannin-containing pomegranate extract: A randomized clinical trial. The Journal of nutritional biochemistry, 42, 126-133.
- Häkkinen, Sari H., Sirpa O. Kärenlampi, Hannu M. Mykkänen, I. Marina Heinonen, and A. Riitta Törrönen. "Ellagic acid content in berries: Influence of domestic processing and storage." European Food Research and Technology 212 (2000): 75-80.
- Xie, L., Roto, A. V., & Bolling, B. W. (2012). Characterization of ellagitannins, gallotannins, and bound proanthocyanidins from California almond (Prunus dulcis) varieties. Journal of agricultural and food chemistry, 60(49), 12151-12156.
- Liu, S., D’Amico, D., Shankland, E., Bhayana, S., Garcia, J. M., Aebischer, P., ... & Marcinek, D. J. (2022). Effect of urolithin A supplementation on muscle endurance and mitochondrial health in older adults: a randomized clinical trial. JAMA network open, 5(1), e2144279-e2144279.
- Pantuck, A. J., Leppert, J. T., Zomorodian, N., Aronson, W., Hong, J., Barnard, R. J., ... & Belldegrun, A. (2006). Phase II study of pomegranate juice for men with rising prostate-specific antigen following surgery or radiation for prostate cancer. Clinical Cancer Research, 12(13), 4018-4026.
- Heilman, J., Andreux, P., Tran, N., Rinsch, C., & Blanco-Bose, W. (2017). Safety assessment of Urolithin A, a metabolite produced by the human gut microbiota upon dietary intake of plant derived ellagitannins and ellagic acid. Food and Chemical Toxicology, 108, 289-297.
