The researchers believe that the antioxidants and fibre found in a combination of grape skin and seeds could be superfoods in the battle against heart attacks.
The latest discovery was given as a dietary supplement to volunteers, who saw their blood pressure reduced by up to five per cent and cholesterol by up to 14 per cent.
During the trials, the compound also improved volunteers' Lipid Profiles - a range of blood tests to diagnose the risk of heart disease.
Many superfoods for the heart, such as the plant extract psyllium or healthy oats, are good for either fibre or antioxidants rather than both.
But the tests at Madrid University on grape antioxidant dietary fibre revealed that it was high in both potentially life-saving ingredients.
Researchers say the grape extract would boost the average Briton's intake of dietary fibre to recommended daily levels of 30g a day.
And combining the supplement with a Mediterranean-style diet which includes oily fish, olive oil and tomatoes would bring even greater health benefits.
Scientists found that mixing the two elements together made the supplement 50 per cent more effective in reducing the risks of heart attacks.
"The effects appear to be higher than the ones caused by other dietary fibres, such as oat, fibre or psyllium, probably due to the combined effect of dietary fibre and antioxidants," The Daily Express quoted Jara Perez Jimenez, the study's lead researcher, as saying.