Olive Oil Linked to Health Benefits : Research: Scientists found less heart disease and lower cholesterol in Italians using the monounsaturated oil instead of butter or margarine.

The health benefits of using olive oil instead of butter may extend beyond controlling cholesterol, according to a study published today that suggests olive oil may also help hold down blood pressure and glucose in the blood.

The study, in the Journal of the American Medical Assn., comes at a time of growing interest in the advantages of so-called monounsaturated fats. Some researchers suspect that those oils may prove more useful than vegetable oils in preventing heart disease.

But specialists in the field cautioned that the latest findings are preliminary. Further research is needed before it can be said with certainty that olive oil is useful against these two additional heart disease risk factors, they said.

“When you do an epidemiological study like this, you can never prove that this is a cause-and-effect relationship,” said Dr. Daniel Steinberg of UC San Diego. “It doesn’t prove that if I went out and started eating olive oil, it would bring down my blood pressure.”

Monounsaturated fats include olive, canola and peanut oils. Polyunsaturated fats include corn, cottonseed, sunflower and safflower oils. Saturated fats usually come from animal sources but also include a few vegetable fats such as cocoa butter.

The researchers, from the United States and Italy, studied more than 4,900 Italian men and women ages 20 to 59. Those who ate a diet relatively high in olive oil had lower levels of cholesterol, blood glucose and blood pressure than those with a diet high in butter or margarine.

Diets high in polyunsaturated fats also appeared beneficial. People who followed those diets also had relatively low cholesterol and glucose levels. However, the effects of polyunsaturated fats on blood pressure were mixed.

“The message here is that in addition to the benefits on serum cholesterol . . . you’re probably going to get a benefit with other risk factors,” said Dr. Maurizio Trevisan of the State University of New York at Buffalo, who headed the study.

The possibility that monounsaturated fats might help control cholesterol is not new. But researchers say there had been little or no evidence that olive oil or vegetable oils might also benefit blood pressure and glucose levels.

The new findings come amid growing interest in monounsaturated fats based on the fact that they not only help hold down cholesterol levels but also appear to improve the ratio of so-called good and bad cholesterol.

“This has raised the question whether we should increase monounsaturated fats rather than polyunsaturated fats (in the diet),” said Steinberg, a professor of medicine at the UC San Diego School of Medicine. “So there’s a lot of interest in olive oil versus . . . polyunsaturated fats.” For example, some have suggested that it might be better to cook with canola or olive oil rather than traditional vegetable oils.

But Steinberg, Trevisan and others urged caution in interpreting the latest results. While certain oils may be associated with reductions in blood pressure and glucose, they said it remains to be shown that those oils actually caused the reductions.

“Associations between certain dietary components and (measures) like glucose or blood pressure can’t be taken as proof that they’re causally related,” said Dr. Scott M. Grundy, director of the Center for Human Nutrition at the University of Texas, Southwestern Medical School. “They are connected, but there may be other intervening factors . . . that have an influence.”