‘Healthy’ Fats May Pose Risk, Research Finds

So-called healthy fats such as olive oil are just as bad as butter in raising levels of a blood clotting factor that may boost the risk of a heart attack or a stroke in the first few hours after a meal, researchers say.

The study did not look at the long-term dangers of various fats; these dangers are well-known. For example, eating saturated fats such as butter raises cholesterol levels, increasing the risk of heart disease.

Instead, the researchers, led by Danish doctoral candidate Lone Frost Larsen, studied what happens to blood levels of Factor VII hours after having a meal high in butter or other fats.

Larsen wanted to understand why Mediterranean people, whose diets are high in olive oil, have a lower incidence of heart disease.

She found that Factor VIIc rose 7% after the high-fat meals, regardless of the type of fat eaten. Factor VIIa was 60% higher.

Factor VII encourages the formation of blood clots, which can, in turn, become lodged in a vessel and cause a heart attack or a stroke.

“It’s not new that Factor VII is activated following a high-fat meal, but I but think it’s new that we could not find any difference between the types of fat,” said Larsen, of the Royal Veterinary and Agricultural University in Frederiksberg.

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The study was published in Tuesday’s issue of Arteriosclerosis, Thrombosis and Vascular Biology, a journal of the American Heart Assn. in Dallas.

Unlike saturated fat, the other main kinds of fat--monounsaturated fat and non-hydrogenated polyunsaturated fat--are good for the heart. Canola and olive oil are high in monounsaturated fat; sunflower oil is high in the non-hydrogenated polyunsaturated variety. Palm oil is high in both saturated and monounsaturated fat.

The student looked at 18 healthy men ages 22 to 33. They participated in six meal tests at least three weeks apart over nine months. For each test, the men fasted, then ate two meals about two hours apart that were either low-fat or enriched with canola oil, olive oil, sunflower oil, palm oil or butter.

The low-fat meals were 6% fat; the high-fat meals 42% fat.

Dr. Alice H. Lichtenstein of the U.S. Department of Agriculture nutrition center at Tufts University in Boston said she was not surprised that olive and canola oil were as bad as butter in raising Factor VII levels.

But she said: “Whether this effect or lack of effect will be reflected in long-term consumption of these diets is yet to be determined.”