10 things to know about olive oil

oliveoilsEvery couple of months, a group of my fellow RDs gets to gather to discuss a nutrition-related topic.  Our latest topic: olive oil, an essential part of the famous Mediterranean diet, thought to provide numerous health benefits.  Here are some of the things we learned:

  1. The health benefits of olive oil may actually be related to the phenol content.  Phenols are a class of antioxidant.  For years, researchers have touted olive oil’s high monounsaturated fat content as the reason for it’s health effects, but that may not be entirely correct.  Extra virgin olive oil is rich in phenol content, which gives the oil color and flavor.  And there’s increasing evidence that those phenols impact vascular health.  Take Away Message: those “light” (colored) highly refined olive oils may not be as healthful as the EVOO varieties.
  2. When it comes to flavor and phenol content, olive oil can be as complex as wine.  The phenols are what gives each oil it’s flavor, and that can vary from year to year according to olive variety, moisture, soil conditions, harvest time, growing season temperatures and the temperature when the oil is pressed.  Saying an olive oil is from Italy or Spain or Australia says little about flavor.  Even within countries, there are countless variations.
  3. Yes olive oil is high in monounsaturated fats, but that may not be the sole reason it’s healthy.  And the percentage of monounsaturated fats isn’t set in stone, but can vary, depending on olive variety and some of those other factors that affect flavor.
  4. “Light” olive oil is not lower calorie.  There is no such thing as lower calorie (or lower fat) olive oil.  The color is probably lighter, which means the phenols have been removed, which also removes most of the flavor.  Colorless olive oil may be made from pomace, the olive paste that’s leftover after the EVOO is pressed out.  The paste can be treated with chemical solvents to extract the last remaining oil.  Take Away Message: if you appreciate olive oil for health benefits, extra virgin olive oil has both high phenol and monounsaturated fat content.
  5. Terms like “first cold pressed” are essentially meaningless when it comes to extra virgin olive oil.  There is only ever one press, no more.  As for “cold”, the temperature is more likely to be “not warm”, and can vary depending on time of year the olives are harvested.  Take Away Message: if it’s EVOO, the olives were pressed once in a non-hot environment.
  6. Olive oil labeling is governed by various trade organizations.  The International Olive Council includes many members from around the world, except for the USA.  The IOO guidelines are followed by most producers, although there have been instances of olive oil adulteration and fraud in the recent past.  The North American Olive Oil Association certifies oil quality from producers who pay to have their oils tested.  The California Olive Oil Council has a similar certification seal, for paying members.  Keep in mind: these are all voluntary.  There is no mandatory standard in the US, although the USDA has issued voluntary guidelines similar to the IOO definitions.  Take Away Message: a certification seal can be helpful when purchasing olive oil, but other reputable producers may not choose to participate in pricey certification programs.  And unfortunately, in the past, some disreputable producers sold inferior oil despite the labeling.
  7. “Packed in Italy” does not necessarily mean “grown in Italy”.  Many inexpensive olive oils are actually blends of oils from several countries.  You can find this hidden somewhere on the back of the label.
  8. While extra virgin olive oil is high in phenols, there is no standard phenol content, no phenol labeling, and concentrations can vary widely.  The average is about 180 mg/kg oil, ranging from 50 to 800 mg/kg oil.  In general, the more phenols, the more bitter the flavor.
  9. The best storage container for your expensive and quality EVOO?  Dark glass or stainless steel.  The worst: clear bottles stored on the counter near heat and light.  If you store olive oil in the refrigerator, it will crystallize a bit.
  10. Don’t cook with extra virgin olive oil at high heat.  While you can sauté at a moderate temperature, high heat will burn the phenols, making them useless and spoiling the flavor of the oil.  Take Away Message: Why do that?  Expensive flavorful extra virgin olive oil is best used as a dressing on salad or as the finishing touch to a pasta, meat or casserole dish.

Some people don’t like olive oil!

I guess I shouldn’t have been surprised at this, but one of the RDs at the meeting pointed out that many of her clients just do not like olive oil.  We all found that interesting, because in fact part of our get-together involved tasting several different kinds of EVOO.  And in fact, we preferred some of those oils over others with very strong tastes.

The oils were from Italy, Spain, Tunisia, Portugal, Greece and California.  And boy were they all over the map in terms of flavor.  Even the flavor descriptions on the containers didn’t necessarily correspond to how each of us perceived the taste.  The Big Picture: as all were EVOO, they all had flavor, as opposed to a colorless bland olive oil.  Obviously phenol content of each one was unique, thanks to the olive variety and growing region.  The colors ranged from yellowy/green to bright green.

The next day I used some of those oils in cooking.  Surprisingly, the one with the “boldest” flavor (we’d all call it strong, and possibly disagreeable) ended up working very well as a dressing on lettuce.  The strong flavor vanished.  Meanwhile the oil grown on rich soil near the ocean tasted nice at the meeting, but ended up with a strangely fishy aftertaste on pasta with feta cheese.  And the oil I’d describe as nondescript gave a lovely finish to a couscous/fresh mozzarella dish.  So, apparently judging an oil at a tasting event doesn’t always tell you how it will work on food.

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