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A Complete Guide to Olive Oil on the Mediterranean Diet (Evidence-Based)

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Olive oil is your go-to cooking oil when on the Mediterranean diet. It is the main cooking oil for Italian, Spanish, Middle Eastern, North African, Greek and Turkish cuisines.

It is an integral part of the Mediterranean diet, but the industry can be a minefield of misinformation. This article will attempt to clarify some common questions people have about olive oil when starting a Mediterranean diet.

What is Olive Oil?

Olive oil is oil pressed from olives, the fruit of olive trees. 

Olives are traditionally found in Mediterranean regions but is popular around the world today.

It is a staple in Mediterranean cuisines and its consumption is thought to be one of the reasons why people in those regions lived to such old ages. 

It is used as the main cooking oil on the Mediterranean diet, as as well for dipping and drizzling on bread, pasta or salads.

Types of Olive Oil

Olive oils differ due to the way they are processed, any additives added and the oil’s level of free oleic acid. It has nothing to do with the type of olives used.

Below are the main olive oils commonly found in supermarkets. They are likely to be a healthier choice than most other cooking oils. However, olive oil is not created equally and there are differences in taste, health benefits, and applications.

Extra Virgin Olive Oil

This is the gold standard for olive oil because it retains the most health benefits when compared to the other olive oils. The fruity, peppery notes of the natural olive fruit are best maintained in extra virgin olive oil (EVOO).

  • Made via mechanical methods without exposure to high heat or chemicals.
  • Unrefined and cold-extracted which retains more compounds and antioxidants that confer health benefits like anti-inflammation.
  • Ranges from green to gold in hue, with aromas from fresh green and grassy to ripe and fruity.
  • Smoke point of 350°F – 410°F (170°C – 210°C), making it suitable for all kinds of lower-temperature cooking like sautéing, light frying, and roasting. However, it flourishes as a finishing or dipping oil.

Virgin Olive Oil

Virgin olive oil is more difficult to find, and it’s likely you’ll need to find it online or shop at a specialist store. It is similar to extra virgin olive oil, but more acidic.

  • Made via mechanical extractions without exposure to high heat or chemicals like EVOO, thus it has similar health benefits and high levels of polyphenol antioxidants
  • The USDA olive oil grading parameters allow minor flavor defects compared to EVOO, which you may not even notice.
  • Range of flavor and aroma.
  • Use as you would an EVOO (light frying, roasting, sautéing, marinades)

Pure Olive Oil or Regular Olive Oil

This is more common than virgin olive oil and can be labeled, pure olive oil, regular olive oil, or simply ‘olive oil’.

  • Combines refined olive oil and 15-25% virgin olive oil.
  • Refined part of the oil is treated with heat or chemicals to remove flavor defects. This reduces the total level of healthy compounds in pure olive oil compared to EVOO/virgin olive oil, but still contains a good amount of these compounds compared to other oils that aren’t olive oil.
  • Neutral flavor and aroma, with a lighter color.
  • Smoke point up to 470°F (240°C), making it great for everyday types of cooking and high-heat cooking methods like searing and grilling.
  • It isn’t a great choice as a finishing or dipping oil because of the neutral flavor.

Light Olive Oil or Extra Light Olive Oil

This is another popular oil you’ll see at the grocery store.

  • Combines refined olive oil and 5-10% virgin olive oil.
  • Like pure olive oil, the refined part of the oil is treated with heat or chemicals to flavor defects. As there is a higher percentage of refined olive oil, this reduces the total level of healthy compounds proportionally more when compared to pure olive oil.
  • The ‘light’ part of olive oil refers to the neutral flavor and aroma, not the number of calories.
  • Smoke point up to 470°F (240°C), making it great for everyday types of cooking and high-heat cooking methods like searing and grilling.
  • It isn’t a great choice as a finishing or dipping oil because of the neutral flavor.

How to Choose the Best Olive Oil

Look for a Fruity Taste

Good quality extra virgin olive oil will taste fruity, pungent, and bright. A really expensive bottle doesn’t necessarily mean a tastier olive oil, so you just want to find one that tastes great for you.

However, a bad olive oil will taste bitter, dirty, and overwhelmingly spicy in order to avoid the poor taste. 

Check the Production Date

Check the production date on the bottle to ensure it’s a current pressing. Extra virgin olive oil will go rancid 12-14 months after pressing. Rancid oil can smell like paint thinner or white spirit and taste more greasy.

Olive oil doesn’t last that long and unlike a fine wine, doesn’t improve with age. Therefore, get the freshest you can and buy too much at once.

Opt For Unflavored Oil

Flavored olive oils are popular. You’ll often see infusings such as lemon, garlic, rosemary and chili, but there are many more.

The problem with flavored oils is that they are often added to mask the taste of low-quality olive oils. There are some exceptions, but if you’re still new to olive oils, it’s best to play it safe.

Choose a Dark Colored Glass Bottle

You will see olive oil come in various types of packaging like plastic bottles, tins and dark glass bottles. The type of packaging is important as it can affect the taste and lifespan of the olive oil.

Plastic bottles should be avoided as they can impact the flavor. Dark-colored glass bottles are better, as they block out the light and prevent the oil from deteriorating.

What are the Health Benefits of Olive Oil?

The main health benefits of olive oil seem from the monounsaturated fat it contains called oleic acid (making up 73% of the total fatty acids in olive oil) and its antioxidant content.

Some of the benefits studies have highlighted about olive oil include:

  • Reduced inflammation: an antioxidant found in olive oil, oleocanthal, has strong anti-inflammatory properties with a similar effect as ibuprofen (1). Studies also find that oleic acid can reduce the levels of inflammatory markers like C-reactive protein (CRP) (23).
  • Protects against heart disease: Lower blood pressure is one of the main factors for heart disease. One study found olive oil reduced the need for blood pressure medication by 48% (4).
  • May help weight loss: although it is higher in calories, studies find that people who consume a lot of olive oil don’t necessarily gain weight. A 30-month study of 7,000 students found that consuming a lot of olive oil wasn’t linked to weight gain (5). One study even found that higher levels of plasma antioxidant capacity, found in those who eat a Mediterranean diet with lots of olive oil, actually reduced body weight over a 3-year period (6).
  • May reduce the risk of stroke: A large review of studies combining 841,000 people found that olive oil was the only monounsaturated fat that reduced the risk of stroke (7).
  • May reduce risk of type 2 diabetes: many studies have linked olive oil to improvements to blood sugar and insulin sensitivity (89).
  • May protect against Alzheimer’s disease: more research is needed in this area of research, but one study indicated that a Mediterranean diet that contained a lot of olive oil benefits brain function (10).
  • May have anti-cancer properties: again, more research is needed in this space, but various test-tube studies find that compounds found in olive oil can fight cancer cells (1112).

Can You Cook With Extra Virgin Olive Oil?

You’ll often see online and from TV shows that you can’t fry and cook with extra virgin olive oil because its smoke point is low and it can be carcinogenic.

EVOO actually has a surprisingly high smoke point of between 350 – 410F (170C – 210C). This makes it useable for many different types of everyday cooking at lower temperatures like sautéing, light frying, and roasting.

You shouldn’t reach its smoking point unless you heat your pan at a very high heat for a long time.

There is also research suggesting that the smoke point isn’t the best indicator of the stability of a cooking oil under heat.

A 2018 study found that it is actually safe to cook extra virgin olive oil at extremely high temperatures and is more chemically stable at those heats than other cooking oils (13).

Does Cooking with Extra Virgin Olive Oil Ruin Its Health Benefits?

You can also hear statements like high heat can ruin its health benefits. 

One study looked at how domestic sautéing changed the polyphenol quantities in extra virgin olive oil.

Polyphenols are what are called reducing agents, and they combine with antioxidants like vitamins C, E, and carotenoids to protect the body’s tissue and thus, health risks like heart disease and inflammation.

The study did find a reduction in polyphenols when sautéing foods (the study used potatoes and chicken). Cooking at lower temperatures (120°C/250°F) resulted in less reduction than at higher temperatures (170°C/340°F).

However, the study concluded that it was a significant factor for some of the polyphenols, but not a significant factor in the total sum of polyphenols (14).

Another study backed up these points. It acknowledged that fatty acids and other compounds are degraded by heat, but it’s still the best cooking oil because it has a high amount of monounsaturated fatty acids, which can resist oxidation better.

Although other oils higher in saturated fats like palm oil do degrade less during cooking, they don’t contain the compounds like polyphenols that give extra virgin olive oil its health benefits.

Essentially, heat does degrade compounds such as fatty acids and other compounds, but not enough that it seriously reduces its health benefits (15).

Don’t Have The Budget for Extra Virgin Olive Oil?

It can be very easy to spend a lot on extra virgin olive oil, particularly if you’re cooking with it.

Although from a health perspective, it is best to both cook and fish with extra virgin varieties, you can save money by using extra virgin olive oil as a finishing oil, and everyday olive oil for cooking purposes.

The flavor stands out more on its own when added at the end, such as in a salad dressing.

Even though the taste differences may not come through as much, there are still health benefits to using extra virgin olive oil for cooking if you can afford it, and what is recommended if you’re following a Mediterranean diet.

How to Store Olive Oil Properly

Olive oil will go rancid faster if it is exposed to sunlight or if it is exposed to constant temperature fluctuations. Therefore, store it away from the stove somewhere that is reliably cool and dark.

To Sum Up

Olive oil is one of the best cooking oils you can use for health reasons.

The highest quality of olive oil is extra virgin olive oil, which is the least refined olive oil. It contains the most antioxidants, confers the most health benefits and has the best flavor.

There are many myths that you shouldn’t cook specifically with extra virgin olive oil, but for most uses, it’s a great choice of cooking oil.

Best quality olive oils will be stored in a dark-colored bottle. The oil itself should have a fruity taste and be unflavored.

It doesn’t age like a fine wine, so be sure to use plenty of it!