How does urolithin A affect the heart?

Urolithin A is produced in the body after eating foods including pomegranates, walnuts, and some berries. Scientists have grown interested in it recently because of its links to healthy aging and mitochondrial function — the process cells use to generate energy.

For the first time, the researchers showed that urolithin A activates a protein called PKGIα. This protein plays an important role in blood vessel function and the relaxation of heart muscle. The compound acts on a specific amino acid within the protein, triggering a pathway associated with cardiovascular benefits.

In animal models, treatment with urolithin A improved measures of heart function by up to 80% compared with untreated models. In laboratory experiments, the compound:

• increased the heart tissue's ability to relax;
• reduced fibrosis, the harmful scarring that interferes with normal heart function;
• limited enlargement of heart muscle cells, helping them maintain more normal function.

Did the compound work in human tissue?

The team also tested urolithin A in engineered human heart tissue created from human stem cells. This laboratory model closely mimics the structure and function of real human heart muscle.

Urolithin A significantly improved relaxation in the engineered tissue. That result suggests, but does not prove, that the effects seen in animals could translate to human hearts.

Unlike many compounds explored as experimental treatments, urolithin A has already been studied in humans and has shown a favorable safety profile — a practical advantage if it moves toward clinical use.

Burgoyne said: "This type of heart failure remains one of the most challenging forms of heart disease to treat. Our findings identify a completely new therapeutic target and show that urolithin A can activate this pathway to improve heart relaxation and reduce disease severity. This raises the exciting possibility of developing new treatments that improve clinical outcomes and quality of life for people living with the condition."

Should you eat more pomegranates?

Not on the basis of this study. Burgoyne cautioned: "While there isn't enough evidence to suggest that people should eat pomegranates to treat heart failure, these findings raise the possibility that dietary approaches that enhance urolithin A production may help alleviate this condition."

Professor James Leiper, Director of Research at the British Heart Foundation, echoed that caution: "While these findings are promising, the benefits have so far been seen in animals and engineered human tissue, so clinical trials involving people are needed to test if this approach is effective for patients. In the meantime, a healthy, balanced diet remains one of the best ways to look after your heart. Eating plenty of fruit and vegetables is linked to better heart health, but it's important to remember that no single food can prevent or treat heart disease on its own."

What happens next?

More research is required before the findings can become treatments. The study's key limitations are clear: the 80% improvement appeared in animal models, and the human evidence comes from engineered tissue, not from patients.

Even so, the results point to two things cardiovascular medicine currently lacks for HFpEF — a promising new therapeutic target in PKGIα, and a naturally derived compound already shown to be safe in humans. Clinical trials in people will decide whether the promise holds.