Our grandmothers always told us to eat walnuts, berries, and pomegranates for heart health. Anything naturally red in colour was considered heart food.
Now scientists agree.
A compound produced by the body after eating foods such as pomegranates, walnuts, and some berries improved measures of heart function by as much as 80 percent in experimental models of a difficult-to-treat form of heart failure, researchers at King’s College London have found.
The study was published in Science Advances and funded by the British Heart Foundation.
According to the researchers, the compound, called urolithin A, appeared to help the heart muscle relax more effectively, while also reducing scarring and harmful enlargement of heart muscle cells.
But before we think pomegranates are the new cure for diseases, remember an important caveat: there is no strong evidence that eating pomegranates can treat heart failure. The findings are from animal models and engineered human heart tissue, and clinical trials in people are still needed.
What is the heart problem being studied?
The research focuses on heart failure with preserved ejection fraction (HFpEF). In this condition, the heart can continue to pump blood effectively, but the heart muscle becomes stiff and does not relax properly between beats. This makes it harder for the heart to fill with blood.
HFpEF accounts for roughly half of all heart failure cases and can cause breathlessness, fatigue, reduced ability to exercise and poorer quality of life.
The condition can be difficult to treat because it is linked to several factors, including ageing, high blood pressure and diabetes. Treatment often focuses on managing these underlying conditions and lifestyle changes.
What did the researchers find?
The researchers found that urolithin A activates a protein called PKG1α, which plays an important role in blood vessel function and heart muscle relaxation.
In animal models, urolithin A treatment improved measures of heart function by up to 80%. It also helped heart tissue relax and reduced fibrosis, or harmful scarring, which can interfere with normal heart function.
The researchers then tested the compound in engineered human heart tissue made from human stem cells. Urolithin A significantly improved relaxation in the tissue, suggesting that the biological pathway may also be relevant to human heart function.
The researchers say the compound has previously been studied in humans and has shown a favourable safety profile.
Should you eat more pomegranates?
Not as a treatment for heart failure.
The study's senior author, Dr Joseph Burgoyne of King's College London, was quoted by Science Daily as saying there is not enough evidence to suggest people should eat pomegranates to treat heart failure.
Professor James Leiper, Director of Research at the British Heart Foundation, was also quoted as stressing that the benefits seen so far have been in animals and engineered human tissue. Clinical trials involving people are needed to establish whether the approach actually works for patients.
For now, the researchers say a healthy, balanced diet remains important for heart health. No single food can prevent or treat heart disease on its own.