The study showed that women who had a diet that was high in antioxidants were five times less likely to have a heart attack.

Researchers followed 32,561 Swedish women aged 49-83 for 10 years. The women completed annual questionnaires in which they were asked how often, on average, they consumed each type of food or beverage during the last year.

The participants were categorized into five groups according to how much antioxidants they ate.

During the study, 1,114 women suffered a heart attack. Women in the group who ate the highest amount of antioxidants had a 20% lower risk; they consumed almost seven servings a day of fruit and vegetables, which was nearly three times more than the women who ate the least amount of antioxidants, an average of 2.4 servings a day.

The researchers highlighted that previous tests have shown that high doses of antioxidant supplements have shown no benefits when it came to heart disease.

"In contrast to supplements of single antioxidants, the dietary total antioxidant capacity reflects all present antioxidants, including thousands of compounds, all of them in doses present in our usual diet, and even takes into account their synergistic effects," said Alicja Wolk, who led the study at the Institute of Environmental Medicine, Karolinska Institute in Stockholm.

The study is published in the October issue of The American Journal of Medicine.