A few years ago, polyunsaturated was the buzz word in health circles. Researchers considered polyunsaturated oils the best substitutes for animal, or saturated, fats, and supermarket shelves sagged under the weight of the new heart elixir: safflower oil.
But that's all changed.
Monounsaturates are now the heart disease preventers of choice. One factor: the news that polyunsaturates might be a cancer agent. And while polys do tend to reduce low-density lipoproteins (LDL), or "bad" cholesterol, they also reduce the high-density lipoproteins (HDL), or "good" cholesterol, which removes cholesterol from the blood stream. (Lipoproteins are a sort of transport system that is in charge of moving cholesterol throughout the body.)
The story changes when monos are substituted for saturated fats. According to research collected by Dr. Scott Grundy at the University of Texas Southwestern Medical Center at Dallas and Dr. Fred Mattson of the University of California at San Diego, monounsaturates reduce LDL cholesterol and maintain and even raise HDL levels. (It should be noted that both the Grundy and Mattson studies were criticized because participants got their supplies of mono, poly and saturated fats from liquid diets. Some wondered whether the results would be the same if the subjects had eaten normally.)
But monounsaturates got a highly publicized scientific stamp of approval anyway. Demand is up for olive, canola and, to some extent, peanut oil. Safflower, corn and other polyunsaturated vegetable oils are gradually falling from favor.
The trendiest of the monos is olive oil. More and more families are using olive oil in their salad dressing. And instead of the traditional pat of butter, many Americans drizzle their dinner rolls with olive oil. It's even appearing as the primary fat in some baked goods.
One Italian study published in the Journal of the American Medical Assn. earlier this year, showed that those who consumed large amounts of olive oil had lower blood cholesterol levels (including LDL), declines in blood pressure and drops in blood sugar compared to those people in Italian provinces with a heavy meat and butter diet. The study was significant because the participants surveyed consumed a normal diet and followed their usual living pattern.
Still, health experts warn against adding indiscriminate amounts of olive oil to the diet. Since it contains the same number of calories as other fats, olive oil should be used, whenever possible, instead of fats such as butter, corn oil, lard and margarine, not on top of an already high-fat diet.
"Because saturated fats are the real culprits in the raising of (blood cholesterol) levels," says Arlene Wanderman, director of the International Olive Oil Council, "it's wise to substitute monounsaturated fats like olive oil--it's a good, healthy food. But I don't think any food is a panacea (to heart disease). Sloshing it all over the place is not the answer."
"The key is that we should use all fats sparingly--be they monounsaturated, saturated or polyunsaturated," says Carolyn Prosak, registered dietitian and spokesperson for the California Dietetic Assn. "Health recommendations say monounsaturates should comprise 10 to 15%, saturates less than 10% and polyunsaturates no more than 10%. Monos have a little better edge in the balance of the total diet."
Prosak thinks olive and canola oils both fit into a balanced diet. It isn't necessary to choose one over the other; instead, she recommends substituting olive oil for animal fats in recipes when a strong flavor is desired and canola oil when taste isn't as important--such as baked goods and stir-fries. (This allows the body's need for saturated fats to be met with other animal foods such as meats and cheeses.)
"I don't even mind people using a small amount of butter for flavor," Prosak said. "A small amount is fine. The whole idea is variety and keeping the total amount low."
Sarah Schlessinger, co-author of "The Low Cholesterol Olive Oil Cookbook" (Villard Books: $19.95), discovered the benefits of olive oil not long after her husband had a heart attack. Her book offers recipes for using olive oil in place of animal fats in a wide assortment of dishes, though she also emphasizes that it is important to limit consumption of total fat, including monounsaturates, to 30% of the day's total calories.
She suggests using olive oil in baking, stir-frying and, she says, "things that you don't normally think of for olive oil" to achieve the cholesterol-lowering benefit.
In her oven-fried chicken, for example, cornmeal and flour coat skinned chicken pieces, and olive oil is lightly drizzled on before baking. Her rum-raisin orange cake calls for a mild, light-flavored olive oil in place of the traditional fat.
"I think that people are surprised to find that olive oil is even in these dishes," she says.