Eating More Of This Fruit May Reduce Plaque Buildup In Arteries
Pomegranates have long been considered a heart-healthy food, thanks to their high levels of plant compounds called polyphenols. But the real benefit might not come from the fruit itself. It may come from what your gut bacteria do with it after you eat it.
A new study explored how one of these gut-made compounds affects artery health in mice1, with results that could change how we think about diet and heart disease.
About the study
Pomegranates are packed with polyphenols, but your body can't absorb most of them directly because they're too large. Instead, your gut bacteria break them down into smaller molecules called urolithins. Researchers at Cardiff University wanted to figure out which of these compounds actually helps protect arteries.
They tested the original pomegranate polyphenol along with several of its breakdown products on human cells in the lab, looking at whether these compounds could reduce cell damage, calm inflammation, and stop cells from absorbing harmful cholesterol. Urolithin A came out on top across the board.
So the researchers took the next step: they gave urolithin A to mice that were prone to clogged arteries and fed them a high-fat diet for 12 weeks.
Smaller plaques and less inflammation, without changing cholesterol
The mice that received urolithin A had noticeably less buildup in their arteries. Their plaques were smaller, and their arteries were less blocked compared to mice that didn't get the compound.
What really stood out was what was happening inside those plaques. The urolithin A group had fewer immune cells, specifically the types that drive inflammation and make plaques more likely to rupture. At the same time, their plaques had more of the stabilizing components (muscle cells and collagen) that help keep them intact and at a lower risk of a dangerous break.
None of this had anything to do with cholesterol levels. The mice showed no changes in total cholesterol, LDL, HDL, or triglycerides. The protection came entirely from reduced inflammation and less cell damage, not from lowering fats in the blood.
What this means for humans
This study was done in mice, so we can't say for certain that the same plaque-shrinking effects would happen in people. But there are reasons to be cautiously optimistic.
The dose the researchers used translates to roughly 4 mg/kg/day in humans, a level that's already being tested in clinical trials for other benefits like muscle health and aging. Human trials have used doses of around 1,000 mg/day for periods ranging from 28 days to four months, showing improvements in muscle function and mitochondrial health. So we know the compound is safe and bioavailable in people; we just don't have human data specifically on artery plaques yet.
The mechanisms urolithin A affected (inflammation, oxidative stress, immune cell activity) are the same ones involved in human heart disease. And the fact that protection wasn't dependent on cholesterol changes is actually encouraging: it suggests a different, complementary route to heart protection beyond the standard "lower your cholesterol" approach.
Why your gut bacteria may determine how much you benefit
Urolithin A isn't actually in pomegranates. Your gut bacteria have to make it for you after you eat the fruit's polyphenols.
And not everyone's gut does this equally well. Some people have the right bacteria to produce lots of urolithin A; others don't. This might explain why studies on pomegranate and heart health have had mixed results. The same fruit could have very different effects depending on who's eating it.
Pomegranates are one of the richest dietary sources of the polyphenols that can be converted into urolithin A. While this study tested the isolated compound rather than whole fruit, the biological pathway is clear: pomegranate polyphenols are broken down by gut bacteria into urolithin A in certain individuals.
For those who want a more direct route, urolithin A supplements have been tested in humans for muscle health and mitochondrial function, though not yet specifically for artery health.
The takeaway
This research suggests that pomegranate's heart benefits may depend less on the fruit itself and more on whether your gut can turn it into urolithin A. In mice prone to artery disease, the compound shrank plaques and reduced inflammation without touching cholesterol levels. Human studies on artery health are still needed, but the findings point to an intriguing gut-heart connection worth watching.