Most people do not eat “Urolithin B” directly. Urolithins are postbiotics that your gut microbes create after you eat foods rich in ellagitannins and ellagic acid, most famously from pomegranate and certain nuts and berries. That means the better question is which foods supply the precursors your microbiome can transform. Here is how Urolithin B is made in the body, which foods provide raw material for that process, and how to eat so you give your gut the best chance to produce it consistently.

What Urolithin B is and where it really comes from

Urolithin B is a small phenolic compound produced when gut bacteria break down ellagitannins and ellagic acid. Scientists have mapped this pathway for more than a decade, showing that not everyone converts at the same rate, and that distinct “metabotypes” exist, including people who produce mostly Urolithin A, those who produce more Urolithin B, and non-producers who generate little to none after eating the same food (described in clinical nutrition and polyphenol metabolism papers throughout the 2010s). Put simply, Urolithin B is usually not present in meaningful amounts in foods on your plate. Your microbiome makes it after you eat specific polyphenols.

Top food sources of ellagitannins and ellagic acid (Urolithin B precursors)

Below are the foods most consistently reported to deliver meaningful precursors. Content varies by variety, growing conditions, and processing, so treat these as directional rather than exact.

• Pomegranate
  The richest and most studied source. Punicalagins, punicalins, and related ellagitannins concentrate in the peel, with notable levels in the arils and fresh juice. Analytical chemistry comparisons repeatedly rank the peel as the most ellagitannin-dense fraction, which is why high-quality extracts and research products often start there rather than the fruit pulp (reported in food chemistry and agricultural journals across multiple comparative studies).
  
  

• Walnuts
  A reliable snack source of ellagitannins and free ellagic acid. Walnut skins carry much of the polyphenol load, and regular intake shows up as measurable urolithin metabolites in human urine and plasma in feeding studies. Walnut varieties differ, but the overall pattern is consistent in nutrition research.
  
  

• Pecans
  Like walnuts, pecans contain ellagic acid derivatives. Human crossover studies that include mixed nut patterns often detect downstream urolithins after pecan intake, though concentrations vary with variety and roasting.
  
  

• Raspberries
  Especially red raspberries, which contain ellagitannins such as sanguiin H-6 and lambertianin C. Processing matters. Freezer storage preserves precursors better than high-heat manufacturing, and whole fruit tends to outperform highly refined products in polyphenol retention.
  
  

• Blackberries and Strawberries
  Both contribute ellagic acid and some ellagitannins. Levels are lower than in raspberries and pomegranate but still meaningful when eaten regularly, as shown in repeated measures designs in food science journals.
  
  

• Cloudberries and certain currants
  Regional berries like cloudberry are naturally rich in ellagitannins. Availability is limited outside northern markets, yet they are frequently cited in compositional surveys.
  
  

• Chestnuts and oak-aged foods
  Chestnuts contain ellagitannins. Oak aging can leach ellagitannin-related compounds into beverages, although the amounts and bioavailability are modest and variable.
  
  

Why pomegranate peel keeps showing up in research and products

If you read laboratory methods sections, you will notice that investigators often use pomegranate peel extracts to study ellagitannin biology, because the peel repeatedly tests as the most concentrated source in the plant. That concentration advantage is one reason many standardized urolithin products trace their lineage to peel rather than arils alone. It is also why a formulation like BioLithin highlights peel-derived Urolithin A and Urolithin B as its starting point.

How much is enough from food

There is no single serving that guarantees Urolithin B production, because your microbiome is the gatekeeper. In feeding trials, some participants excrete robust urolithin metabolites after standard servings of pomegranate, walnuts, and berries, while others show little change. This variability is often summarized as metabotypes A, B, and 0 in clinical papers, reflecting dominant production of Urolithin A, Urolithin B, or none. The takeaway is practical. Eat a rotation of ellagitannin-rich foods often, then consider targeted supplementation if you want consistent exposure independent of microbiome differences.

How to build a plate that favors Urolithin B formation

• Rotate the heavy hitters weekly. Include pomegranate arils or a small glass of minimally processed pomegranate juice, a few servings of walnuts or pecans, and several cups of berries across the week. Variety covers gaps in crop and seasonal variation.
  
  

• Keep the matrix intact when possible. Whole fruit and nuts provide fiber that slows digestion and feeds the very microbes responsible for converting ellagitannins. Highly refined products often lose that synergy.
  
  

• Support the microbiome. A Mediterranean-style pattern rich in diverse fibers and polyphenols, fermented foods, and modest added sugars encourages the bacterial guilds that carry out ellagitannin metabolism, a point echoed in microbiome-focused nutrition studies.
  
  

• Be patient. Microbial communities adapt over weeks, not days. Consistency matters more than occasional large servings.
  
  

Frequently asked questions about foods and Urolithin B

Can I just drink pomegranate juice? Fresh, minimally processed juice can contribute precursors, although peel concentrates more ellagitannins than juice. If juice is your choice, favor low-heat, low-sugar options and treat it as one item in a broader rotation.

Are powders as good as fruit? Some freeze-dried powders preserve polyphenols well. Others are heat-treated and lose activity. Read processing notes, and remember that whole foods deliver fiber that powders may not.

Do roasted nuts still work? Light roasting preserves more polyphenols than high-temperature roasting. If you enjoy roasted nuts, choose lighter roasts and keep nuts fresh to protect skins where many phenolics live.

Can I get Urolithin B directly from food? Not in meaningful amounts. You get precursors from foods, then your microbiome converts them to Urolithin B, which is why people’s responses differ.

Why some people get more Urolithin B than others

Age, antibiotics, habitual diet, and even oral hygiene influence the microbes that transform ellagitannins. Research teams have documented stable metabotypes in individuals over time, although diet shifts can nudge production. That is why two people can eat the same pomegranate salad and show very different urolithin patterns afterward in their blood or urine. If you suspect you are a low converter, you can still benefit from the whole-food pattern for many reasons, and you can consider a standardized supplement to guarantee exposure while you work on the diet that builds a supportive microbiome.

Where BioLithin fits if you want consistency

Food first is a smart foundation, yet it cannot control conversion. BioLithin provides Urolithin A and Urolithin B directly, sourced from pomegranate peel, and pairs them with taurine for mitochondrial support. This approach gives you the downstream molecules every day regardless of metabotype, while your whole-food pattern continues to feed the microbes that make additional postbiotics and supports overall cardiometabolic health.

Sample one-week food plan for precursors

• Mon: Greek yogurt with raspberries and chopped walnuts, big salad at lunch, grilled salmon with veggies.
  
  

• Tue: Oats with strawberries, handful of pecans, lentil bowl with leafy greens.
  
  

• Wed: Cottage cheese, blackberry and chia bowl, olive-oil dressed grain salad, roasted chicken and vegetables.
  
  

• Thu: Smoothie with frozen pomegranate arils and yogurt, quinoa tabbouleh, tofu stir-fry.
  
  

• Fri: Eggs with sautéed greens, walnut snack, bean and veggie chili.
  
  

• Sat: Whole-grain pancakes with berries, nuts on top, big leafy salad, lean protein of choice.
  
  

• Sun: Cloudberry or blackberry compote if available, mixed-nut trail mix, Mediterranean-style dinner with legumes and greens.

This rotation is not about perfection. It is about giving the microbiome repeated chances to convert precursors into Urolithin B while you build a diet that stands on its own for fiber, polyphenols, and healthy fats.

Key takeaway

No food reliably “contains” Urolithin B in the way an orange contains vitamin C. Your gut makes Urolithin B after you eat ellagitannin-rich foods, led by pomegranate and joined by walnuts, pecans, raspberries, blackberries, strawberries, and chestnuts, with regional berries like cloudberries contributing when available. Because conversion depends on your microbiome, the most dependable strategy is a consistent whole-food rotation plus a standardized urolithin supplement if you want guaranteed daily exposure.

This content is for informational purposes only and is not a substitute for medical advice. Always consult a qualified healthcare professional before making significant dietary changes or starting supplements, especially if you manage medical conditions or take prescription medications.