Olive Oil: Powerful But Fragile

Olive oil

Rich in monounsaturated fat, olive oil has well-documented health benefits.  Also, it's loaded with important, health-promoting phytonutrients.  But not all olive oils are equal, and their many nutrients need to be protected from light and excessive heat.

Omega-9 Fatty acids

The monounsaturated fats that olive oil contains are also known as omega-9 fatty acids. In addition to lowering total cholesterol and bad cholesterol (LDL), increasing good cholesterol (HDL), lowering triglycerides and blood pressure, and even helping to control blood sugars, exciting new research suggests that monounsaturated fat may also help to reduce abdominal fat.

Body weight and Fat Mass

Abdominal fat, or in other words the visceral fat that surrounds our internal organs, fuels a vicious cycle of inflammation, insulin resistance, and further fat deposition.  This places us at greater risk for heart disease, stroke, metabolic disorders, and certain forms of cancer.  Studies have shown that substituting monounsaturated fatty acids, including those found in olive oil, for the saturated fats in your diet can translate into a small but significant loss of both body weight and fat mass, without changing anything else about your diet or increasing your physical activity.

Phytonutrients called polyphenols contained in olive oil provide even more amazing health benefits in addition to those provided by its monounsaturated fats.  Fresh, high-polyphenol olive oil reduces our risk for metabolic syndrome (the name for a group of risk factors such as high blood pressure, elevated cholesterol and poor glucose control) by depressing the genes that activate these factors, and thereby decreasing our risk for heart disease.  They also reduce inflammation and cell damage and protect us from infections.  Unfortunately, according to the Agricultural Research Service, most commercially available olive oils are low in many of these polyphenols.

How long does olive oil last?

The polyphenol content and health benefits of olive oil diminish as the days, weeks, and months go by after the fruit is harvested and pressed.  Olive oil has a maximum two-year shelf life from the time of harvest; this may be indicated on the bottle.  If more than a year has passed from the harvest date, don't buy it.

The less processing the oil undergoes, the more phenols it will contain. "Extra virgin" olive oil, which is pressed without heat only one time, has the highest level of polyphenols.  Two presses ("virgin" olive oil), reduces the polyphenol content, and oil with three extractions contains only about half the level of polyphenols contained by "virgin" olive oil.  Highly refined or "light" olive oils, which use heat or chemicals in the refining process, have much lower polyphenol levels still.  The term "light" refers to the oil's color and flavor.  Be aware that heat, light, and air can affect the taste of olive oil and possibly its health-promoting nutrients.  Store olive oil in a dark cupboard at room temperature, or even in the refrigerator.

Heating olive oil

Pomegranite Vinaigrette Ingredients clear background

Heating olive oil is tricky since it starts to break down chemically and loses many of its phytonutrients.  Toxic chemicals in the form of smoke are released, and disease-causing, carcinogenic free radicals are created at temperatures above 225 - 250 degrees F.  Different companies list different smoke-points for their olive oil products, which reflects the differences in the degree of processing that the oils undergo.  The more processed the oil, the higher its smoke point.  Consequently, organic, unrefined, cold-pressed extra virgin olive oil (EVOO) has the lowest smoke-point, as this form of the oil is the least refined and most nutrient-dense – but these nutrients are extremely fragile, so it’s better not to use extra-virgin olive oil to cook above low temperatures.  Use EVOO for vinaigrettes, sauces, sautéing, and to add a finishing touch.  Fine virgin or virgin olive oil has a smoke point of about 350 degrees F so it’s perfectly fine to use it with medium-low heat.  Refined or “light” olive oil has a smoke point of around 400 degrees F, so medium heat would be acceptable, but not high heat.  This is just an estimate, however.  Stove temperatures vary greatly, as no two cooktops are calibrated equally.  Never cook with olive oil at high heat.

Olive oil stores are popping up all around the country these days.  Find one near you for the freshest oils with the highest levels of polyphenols.  Often the oils come from California and are infused with all sorts of herbs, spices and fruits.  Pour them into an olive oil mister and use them to flavor fish, chicken, air-popped popcorn and more.  I keep one mister full of olive oil infused with Tuscan herbs, lime, and a plant combination that tastes like butter.  I use various oils after cooking and prior to serving, depending on the flavor I want to achieve.  For instance, after cooking fish I’ll give it a spray of olive oil infused with lime, or whichever flavor suits my current mood.  The mister allows the oil to disperse over the entirety without drenching it in oil, spreading the flavor and moisture evenly.

Use extra virgin olive oil within its appropriate heat range to take full advantage of its powerful phytonutrients.  Try using it on salads to enhance the nutrients already in the salad, or to finish vegetables after they're cooked.  This easy Tuscan Pomegranate Vinaigrette only has four ingredients and requires no chopping.  It's delicious and perfect for the holidays.  Take December's Healthy Challenge (2013) and replace other fats with olive oil when no heat or very low heat is involved. A bottle of extra virgin olive oil infused with lime, Tuscan herbs, or a butter-tasting plant, along with an oil mister, makes an awesome gift!