Show Notes
Urolithin A: What It Is, How It Works, and Why Your Gut Decides Everything By Dr. Terry Simpson Most people hear the name Urolithin A and think it belongs in a commercial about prostate health. It sounds like something a man named “Gary, 62,” would talk about while fishing. But Urolithin A has nothing to do with plumbing. Instead, it sits at the center of a new wave of longevity science focused on how our cells clean up old, broken parts. As we age, our mitochondria—the tiny power centers inside our cells—start to slow down. They build up damage and stop working well. Eventually, this pile-up makes us lose strength and energy. That’s where Urolithin A comes in. It helps switch back on a process called mitophagy, which is basically the cell’s recycling program for old mitochondria. Where Urolithin A Really Comes From You cannot eat Urolithin A directly. Instead, your body makes it when your gut bacteria break down special plant compounds called ellagitannins. These are found in foods like: pomegranates walnuts berries green tea (yes, really)
Green tea is usually known for its catechins, but it also contains ellagitannins like strictinin. After you drink it, your gut bacteria break these tannins apart and create ellagic acid, which can later turn into Urolithin A. However, this only works if you have the right microbes. And here’s the surprising part: Most people do not. Studies show that only 12% to 40% of adults naturally produce Urolithin A from food. Everyone else makes little to none because their gut bacteria simply aren’t built for the job.
How Your Gut Decides Everything Your microbiome—the community of bacteria living in your digestive system—decides whether you make Urolithin A or not. People who produce Urolithin A usually have: more diverse gut microbes special bacteria like Enterocloster and Gordonibacter the right genes inside those microbes to do the chemical conversion
People who don’t produce it (called “metabotype zero”) lack those bacteria or the gene pathways needed. Eating more pomegranates or drinking more green tea does not fix this. No diet, including keto or Mediterranean, has been shown to turn a non-producer into a producer. This is why two people can eat the same food, and only one makes Urolithin A.
What Urolithin A Does in Humans In older adults, researchers have tested Urolithin A supplements for up to 4 months. These studies show several encouraging results: muscle endurance improves inflammation markers decrease mitochondrial health markers look better
Even so, there are limits. Trials show no meaningful improvement in: walking distance ATP (cellular energy) production overall physical function
So the biology looks better, but major clinical outcomes have not changed.
What Happens in the Lab (But Not Yet in Humans) Scientists also study Urolithin A in senescent cells—cells that have stopped dividing but still cause inflammation. In the lab, Urolithin A can: reduce senescence markers calm inflammatory signals restore mitophagy improve oxidative stress even strengthen circadian rhythms inside aging cells
All of this sounds exciting. However, these findings are from cell culture, not humans. They give us clues, not guarantees.
Food vs Supplements You cannot get Urolithin A directly from food. You only get the precursors, and only people with the right gut bacteria turn those precursors into Urolithin A. Supplements bypass the microbiome entirely and give everyone measurable Urolithin A, even non-producers. Foods that contain ellagitannins include: pomegranates walnuts raspberries blackberries some teas, especially green tea
But none of these will raise Urolithin A levels if your gut bacteria cannot perform the conversion.
Is Urolithin A Safe? Short-term human studies show that Urolithin A is safe and well-tolerated. Most people experience no side effects. When side effects do show up, they are usually mild digestive symptoms like bloating or softer stools. What we don’t know: long-term sa
More from Fork U with Dr. Terry Simpson
With all the spices we have access to, it is amazing how bland recipes have become. I have many cookbooks, some from great chefs, television personalities, and friends. What I am always surprised by is how bland the food has become. People seem to think a bit of salt, pepper, maybe onions, and garlic provide the spices one needs. Perhaps it is because some associate spice with heat. Mostly because many have never experimented with some of those great warm spices available. A pinch of coriander, some freshly ground cumin, a little cardamom, or a touch of cinnamon can turn an ordinary dish into something remarkable. And the most astonishing part is that these spices financed voyages around the world, built cities, created fortunes, and caused people to kill one another. Without the spice trade, it is safe to say that the United States, as we know it, would be vastly different from what it is now. The money loaned to the United States, when we were a fledgling country, came from the wealthy spice merchants from what was considered one of the great hyperempires of the world, based in Amsterdam. But before we go to the birth of the United States, let me take you to the meatball.
Tea: The Drink That Built an Empire—and Helped Break One China had the tea. Britain had the appetite. John Hancock had a business to protect.
MesoAmerica and Chocolate In our series looking at foods that built civilizations, today we are going to stay in the Americas with chocolate. Chocolate has been used as currency, consumed by kings, incorporated into religious ceremonies, and prescribed as medicine. Today, it is a multibillion-dollar industry that wants you to believe that eating chocolate is an act of preventive cardiology. I mean, why not? They convinced us to give chocolate to people we love, eat it when we are happy, when we are sad, when only the dog understands us. Don’t feed chocolate to your dog. And we have done all this with a bitter seed that most of us would probably spit out if we tasted it straight from the tree.
I’ve been doing a series about foods that built civilizations. In this episode, we are talking about the potato. It is difficult to imagine that thousands of years ago, people constructed large buildings, managed rivers, built monuments, and created art. We have glimpses of these civilizations through stories, archaeology, and the structures they left behind, but much of their history has been lost. Imagine, we don’t even know where Cleopatra or Alexander the Great are buried, yet we know their stories. As European powers conquered Indigenous peoples, their languages, cultures, and oral traditions were suppressed. When a language disappears, so are the stories preserved within it. Our clues come from archaeology when we uncover a monument, a building, or an ancient settlement. In the Andes, the potatoes they cultivated were not the Russets, Yukon Golds, or fingerlings you find in the store today. Different colors, shapes, and textures. Adapted to survive the elevations, temperatures, and growing conditions. Biodiversity protected their food supply against frost, disease, and changing environmental conditions. If one variety failed, another might survive. The ancient wisdom of diversity that Andean farmers developed over thousands of years was lost when the potato eventually reached Ireland.
In our series about foods that built civilization, we talked a lot about grains, from wheat to corn to rice. Today, we are taking you to the ocean, with the civilizations that salmon built. From California to the interior of Alaska, salmon, a staple, allowed people to settle into villages, develop complex social networks, art, and trade routes. Those trade routes are as large as the ones in the Mediterranean. Some tribes built communal homes and developed complex art and language. Some were Seafaring tribes with canoes up to 60 feet long that traveled across oceans. All because there was a fish that would return in large numbers to streams and rivers, reliably, predictably. So predictable, the people could build their lives around salmon runs. So much so that some built a calendar not only with lunar cycles, but also with the return of the salmon. Civilizations have always gathered around food and water. The Mediterranean connected people who grew wheat and olives, giving people time to make wine, mine copper, build ships, trade with their neighbors, and occasionally go to war with them. Asia had rice and grain near the great river systems. The reliable calories from rice and grains allowed villages to become cities and to travel by water to trade. Today we are going to my home, from the Ventura River in California to my home state of Alaska.