All About Olive Oil

Last Editorial Review: 4/22/2005

Tips for using this healthy, flavorful oil

By Elaine Magee, MPH, RD
WebMD Weight Loss Clinic - Feature

Reviewed By Charlotte E. Grayson, MD

This oil's got history going for it, that's for sure. One of the oldest known cultivated trees in the world, the olive tree is native to Asia Minor. It is thought to have spread to the Mediterranean region -- now well-known for its use of olive oil -- about 6,000 years ago.

You can buy domestic olive oil (using mostly Californian grown olives) or imported oils from France, Greece, Spain, and Italy.

This uniquely green and flavorful oil can be less green and less flavorful, depending on the type you buy. If you want to use it at high temperatures or in baking, try one of the "light" olive oils. This type goes through a fine filtration process, producing lighter-colored oil that lacks the classic olive flavor.

What if you want a fragrant and flavorful oil, for salad dressings or for adding to a dish after cooking? Olive oil that's extra-virgin and cold-pressed (a chemical-free process that involves only pressure, producing an oil with low acidity) is considered the fruitiest and finest type, according to The Food Network's online encyclopedia.

More and more people are cooking with olive oil, perhaps because Mediterranean cuisine is in vogue, or because of the oil's distinctive flavor, or its potential health benefits. How about all of the above?

A Smart Fat

Nutrition experts consider omega-3 fatty acids, a type of polyunsaturated fat found in fish and some plant foods, to be a "smart fat." The other "smart fat" is monounsaturated fat -- the type olive oil is rich in.

Environmental Nutrition (The Newsletter of Food, Nutrition & Health) recommends that monounsaturated fats make up most of your fat intake, with polyunsaturated fats comprising the rest, according to Luanne Hughes, MS, RD.

Unsaturated fatty acids, whether monounsaturated or polyunsaturated, can lower your levels of "bad" cholesterol (which decreases your risk of heart disease) if you eat them instead of saturated fatty acids, Hughes says. Saturated fat -- found mostly in animal products and in palm and coconut oils -- is the main dietary cause of high blood cholesterol, according to the American Heart Association.

Here's a breakdown of the fat makeup of some different types of vegetable oils:

Type of oil
% Monounsaturated fat
% Polyunsaturated fat
% Saturated fat
Hazelnut oil
Olive oil
Almond oil
Canola oil
Peanut oil

And the oil that's readily available, usable in a variety of dishes, relatively reasonably priced (unless you buy a gourmet variety) AND has the highest amount of monounsaturated fat is none other than ? drum roll, please ? olive oil!

In fact, the FDA now allows olive oil labels to carry the claim that its monounsaturated fat can reduce heart disease risks -- with a few strings attached. The claim says that "limited and not conclusive scientific evidence" suggests that eating about 2 tablespoons of olive oil daily may reduce the risk of heart disease. To give this possible benefit, it adds, the olive oil must replace a similar amount of saturated fat in your diet -- and must not increase the total calories you eat in a day.

The potential health benefits of olive oil don't stop at heart disease.

Recent studies have suggested that, of all the fats we can choose -- aside from the omega-3s found in fish -- monounsaturated oils are the least likely to promote cancer.

And monounsaturated fat isn't the only thing olive oil has going for it nutritionally. Some olive oils come with phytonutrients that may offer their own disease protection benefits (still, it's not clear whether most of us can take in enough of these phytonutrients without going overboard on olive oil, says Joyce Nettleton, DSc, RD, researcher and editor of the PUFA Newsletter).

And, of course, olive oil is a key component of the well-studied Mediterranean diet, the others being a bounty of fruits, vegetables, nuts, and whole grains. Several studies have shown that this type of diet may have many health benefits, from adding years to the lives of healthy older adults, to lowering the risk of metabolic syndrome.

Nettleton prefers to use both olive and canola oil for cooking, depending on what she's making.

"I think that much more has been claimed for olive oil than the [scientific] data permit," she explains. "And having some plant omega-3s in the diet (which canola oil helps provide) is probably desirable, in part because it displaces the relatively large amount of omega-6s we now consume."

Ideally, our intake of omega-6 fatty acids and omega-3 fatty acids would be balanced. But Americans tend to eat too much omega-6, which is found in corn oil and some other vegetable oils. Too much omega-6 can raise blood pressure, lead to blood clots, and cause other health problems.

It's important to remember that any oil -- even a "healthy" oil -- contains plenty of calories.

The popular Italian-restaurant practice of dipping bread in olive oil is an easy way to enjoy some olive oil, but don't get too dip-happy. Armed with enough bread, you can easily consume 3 tablespoons of olive oil. That's a total of 360 calories, not including the bread!

Calories from fat add up to fat on your body, according to dietitians from the Environmental Nutrition newsletter. The easiest way to limit foods that are high in total fat as well as in "bad fats" is to eat fewer processed foods and more whole foods, including fruits, vegetables, and whole grains, they say.

Storing and Using Olive Oil

How long you can store olive oil depends on how you store it.

In the worst-case scenario -- unfiltered, late-harvest olive oil bottled in clear glass and sold from a supermarket shelf above hot deli foods -- you can store it for about three months. In the best-case scenario (early-harvest, filtered oil in a sealed tin or dark bottle and stored in a cool, dark place - it will stay good for about two years.

Still, it's probably a good idea to use it sooner than that. Research published in the May issue of Food Chemistry found that levels of antioxidants in olive oil fell sharply after 12 months in storage -- even under the best of storage conditions.

Here are four ways to keep the antioxidant levels in your olive oil high:

  • Buy olive oil in amounts you will use within 6 months.
  • Buy it from busy stores that are likely to sell a lot of olive oil (to ensure that it hasn't been sitting on the shelf for very long).
  • Store it in opaque, airtight bottles or metal tins, away from light and heat.
  • If you keep it in the refrigerator, it is less likely to go rancid). Refrigerated oil will become cloudy and thick -- but don't worry. It will still have the same quality and taste, and will become liquid and clear again when brought back to room temperature.

Olive Oil Recipes

Perhaps the best reason for using olive oil is its distinctive flavor. It adds zip to everything from pesto sauce to meats to roasted veggies (you can even use milder varieties for baking). Here are recipes for a couple of savory dishes to get you started.

Basil Bread

Journal as: 1 slice bread + 1 teaspoon oil
OR 1 slice bread + 1 tablespoon nuts

1 cup fresh basil leaves, slightly packed
1/4 cup toasted pine nuts (toast by heating in nonstick skillet on medium heat, stirring often, until golden brown)
1/4 cup extra-virgin olive oil
1/2 cup shredded Parmesan cheese
Pinch salt (optional)
10 inch-thick slices of French or sourdough bread, preferably made with part whole-wheat flour

  • Put all of the ingredients except the bread in a small food processor. Pulse briefly to blend well.
  • Spread about 1/2 tablespoon spread on each bread slice and place on foil-lined cookie sheet. Broil about 6 inches from heat, watching carefully, until spread is bubbly and lightly brown (two-three minutes).

Yield: 10 pieces

Per slice of bread with spread (using part whole-wheat French bread): 132 calories, 4 g protein, 12 g carbohydrate, 8 g fat (1.5 g saturated fat, 4.9 g monounsaturated fat, 1.3 g polyunsaturated fat), 2 mg cholesterol, 1.3 g fiber, 150 mg sodium. Calories from fat: 54%.

Lemon Garlic Skillet Chicken

Journal as: 1 serving of "lean meat and moderate fat meat without added fat"

4 teaspoons extra-virgin olive oil
1 tablespoon fresh or bottled minced garlic
4 boneless, skinless chicken breast halves (unfold the tenderloin area to make the breast as flat as possible)
Freshly ground black pepper
3 tablespoons Meyer lemon juice (or substitute regular lemon juice)
4 tablespoon water, chicken broth, or white wine

  • Add olive oil to a large, nonstick skillet and begin to heat over medium-high heat.
  • When hot (a minute or two), add garlic and chicken breasts (placing them so they are nice and flat and covering the olive oil in the bottom of the skillet). Brown for two-three minutes, sprinkle the top with pepper, then flip to brown the other side for two to three minutes.
  • Turn heat down to LOW and drizzle the lemon juice and water, chicken broth, or wine over the top. Cover skillet immediately and cook until chicken is cooked throughout (about 15 more minutes).
  • Serve the chicken with or without the lemon broth in the bottom of the skillet.

Yield: 4 servings

Per serving (with broth from pan): 188 calories, 27 g protein, 2 g carbohydrate, 7.5 g fat (1.5 g saturated fat, 4.4 g monounsaturated fat, 1 g polyunsaturated fat), 73 mg cholesterol, 0.1 g fiber, 64 mg sodium. Calories from fat: 37%.

Published March 25, 2005/

SOURCES: Environmental Nutrition, June 2003; May 2004; February 2005. The Journal of Pediatrics, July 1995. Journal of the American Dietetic Association, February 1997. Journal of the American Dietetic Association, July 1997. Journal of the American Medical Association, 2004; 292. Food Chemistry, May 2004, vol 85; issue 3. American Journal of Clinical Nutrition January 2005. FDA News, Nov. 1, 2004. The Olive Oil Source web site.

©2005 WebMD Inc. All rights reserved.


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