Experts believe the benefits come from the high content of flavonoids in berry fruits, which appear to combat blocked arteries, the 'Daily Mail' reported.
Flavonoids are antioxidant compounds found in plants, as well as tea and red wine, which can protect against a wide range of diseases, including heart disease, hypertension, some cancers and dementia.
The findings are from an ongoing study of nurses which involves only women, but may also apply to men, researchers said.
The study involved 93,600 participants in the Nurses' Health Study II, a major US investigation of women's health.
Women aged 25 to 42 completed questionnaires about their diet while their health was monitored over 18 years.
During the study, 405 heart attacks were recorded.
Women who ate the most strawberries and blueberries - at least three times a week - were at 32 per cent lower risk than those consuming the berries once a month or less.
Even participants with diets rich in other fruits and vegetables were more likely to experience heart attacks if they avoided strawberries and blueberries.
"Blueberries and strawberries can easily be incorporated into what women eat every week. This simple dietary change could have a significant impact on prevention efforts," Dr Eric Rimm, one of the senior study authors from the Harvard School of Public Health in Boston, said.
Scientists believe the protective effect could be linked to anthocyanins, a type of flavonoid that may help open up arteries and counter the build-up of fatty deposits on blood vessel walls.
"We have shown that even at an early age, eating more of these fruits may reduce risk of a heart attack in later life," Nutritionist Dr Aedin Cassidy, from the University of East Anglia, who took part in the research, said.
"This study found an association between a diet rich in red and purple fruits, such as blueberries, blackberries and strawberries, and a reduction in heart attack risk for young and middle aged women," Victoria Taylor, Senior Dietitian at the British Heart Foundation, said.
"However, more research is needed to understand why this link between berries and better heart health exists. We would need to know more before we make specific recommendations about individual fruit and vegetables in relation to heart disease," Taylor said.
The study was published in the American Heart Association journal Circulation.
