Olive and sunflower oil fried food not bad for heart: Study

By Dr. Ananya Mandal, MDJan 26 2012

A new study shows that all fried foods may not be bad for the heart – particularly those fried in olive or sunflower oil.

A study published this week in the British Medical Journal analyzed data on 40,757 Spanish adults age 29 to 69 who were followed for an average 11 years. Free of coronary heart disease at the beginning of the study, they were asked what they ate and what cooking methods they used, then were tracked to see who developed coronary heart disease and who died.

During those 11 years, there were 606 events linked to coronary heart disease, such as heart attack or chest pain, and 1,135 people died from all causes. Analysis showed that eating fried foods was not associated with incident coronary heart disease or coronary heart disease events, even after adjusting for various factors such as calorie intake, age, sex, body mass index and high blood pressure.

The study authors, led by Professor Pilar Guallar-Castilon from Autonomous University of Madrid, concluded that, “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.”

The types of oils used to fry foods - olive, sunflower or other vegetable oils also did not change outcome. Eating fried foods cooked with those oils was also not linked with death from all causes. On average the study participants ate about five ounces of fried food a day, or about 7% of their total amount of food. As for what oil they used for frying, 62% used olive oil, and the rest used sunflower or other types of vegetable oil. Of all fried food eaten, 24% was fish, 22% was meat, 21% were potatoes and 11% were eggs.

Frying foods with some types of oils or solids, such as partially hydrogenated vegetable oil, can increase intake of trans fats, considered the worst type of fat since it raises bad cholesterol and lowers good cholesterol. When food is fried, it loses water and absorbs the cooking oil. Oil degrades the more times it is used, leading to an increase in saturated fats and trans fats.

Researchers add that one of the study's limitations was that researchers couldn't separate the effects of frying with oil from the food that was fried, such as fish, some of which is high in omega-3 fatty acids, shown in some studies to be beneficial for heart health.

“The bottom line here is, most of what they were consuming were these healthful oils - olive and sunflower - and a lot of fish,” Andrea Giancoli, a Santa Monica, California dietitian and spokesperson for the Academy of Nutrition and Dietetics, told WebMD. “The Mediterranean diet is different from ours.”

In an accompanying editorial, Professor Michael Leitzmann from the University of Regensburg in Germany said, “Taken together, the myth that frying food is generally bad for the heart is not supported by available evidence. However, this does not mean that frequent meals of fish and chips will have no health consequences. The study suggests that specific aspects of frying food are relevant, such as the oil used, together with other aspects of the diet.” Mediterranean diets have long been hailed as healthy, being packed full of low-fat, high-fibre fresh fruits and vegetables, as well as fresh fish.

Victoria Taylor, a senior heart health dietitian at the British Heart Foundation, said, “Before we all reach for the frying pan, it's important to remember that this was a study of a Mediterranean diet rather than British fish and chips. Our diet in the UK will differ from Spain, so we cannot say that this result would be the same for us too. Participants in this study used unsaturated fats such as olive and sunflower oil to fry their food. We currently recommend swapping saturated fats like butter, lard or palm oil for unsaturated fats as a way of keeping your cholesterol down and this study gives further cause to make that switch.” “Regardless of the cooking methods used, consuming foods with high fat content means a high calorie intake. This can lead to weight gain and obesity, which is a risk factor for heart disease. A well-balanced diet, with plenty of fruit and veg and only a small amount of high fat foods, is best for a healthy heart,” she added.