Lead investigator Alicja Wolk of the Karolinska Institute in Stockholm, Sweden, tracked 32,561 Swedish women ages 49-83 from September 1997 through December 2007.
The women completed a food-frequency questionnaire in which they were asked how often, on average, they consumed each type of food or beverage during the last year.
The investigators calculated estimates of total antioxidant capacity from a database that measures the oxygen radical absorption capacity of the most common foods in the United States because no equivalent database of Swedish foods exists, Wolk said.
The women were categorized into five groups of total antioxidant capacity of diet.
"Our study was the first to look at the effect of all dietary antioxidants in relation to myocardial infarction," Wolk said in a statement. "Total antioxidant capacity measures in a single value all antioxidants present in diet and the synergistic effects between them."
The study, published in The American Journal of Medicine, found with the highest total antioxidant capacity had a 20 percent lower risk, and they consumed almost seven servings per day of fruit and vegetables, which was nearly three times more than the women with the least antioxidant capacity, who on average consumed 2.4 servings.