The study was conducted in Spain, a country in the Mediterranean where sunflower or olive oil is used for frying. The researchers stress that their results would probably not be the same in countries which primarily use solid and re-used oils for frying.
One of the move prevalent cooking methods in the Western Hemisphere is frying. Food absorbs the fat of the oils when fried, increasing the amount of calories in the food.
Although consuming high quantities of fried food can increase some heart disease risk factors, such as obesity, hypertension and high cholesterol, investigators have not fully researched the association between heart disease and fried food.
Therefore the researchers, led by Professor Pilar Guallar-Castillón from Autonomous University of Madrid, surveyed 40,757 adults aged between 26 to 69 years old over an 11-year period about their cooking methods. At the start of the study, none of the participants had heart disease.
The researchers defined fried food as food for which frying was the only cooking method used. Participants were asked questions about their diet and cooking methods, in addition to questions, such as whether food was fried, crumbed, battered or sautéed.
The participants' diet was divided into four ranges of fried food consumption, the first range related to the lowest amount of fried food consumed and the fourth range related to the highest amount.
1,134 deaths were observed during the follow-up period as well as 606 events associated to heart disease.
The researchers conclude:
"In a Mediterranean country where olive and sunflower oils are the most commonly used fats for frying, and where large amounts of fried foods are consumed both at and away from home, no association was observed between fried food consumption and the risk of coronary heart disease or death."
In an associated report, Professor Michael Leitzmann from the University of Regensburg in Germany, explains that the study investigates the myth that "frying food is generally bad for the heart," although he stresses that this "does not mean that frequent meals of fish and chips will have no health consequences." Leitzmann adds that specific aspects of frying food are relevant, such as the type of oil used.