Spotlight on: Olive oil

Dietary oils play a crucial role in maintaining a healthy diet. However, with the increasing number of oils available, it is often a challenging task selecting the best oil for our needs. Enter olive oil, the main and most characteristic component of the Mediterranean diet. This oil is known worldwide for its numerous health benefits. It is rich in monounsaturated fats, antioxidants, and anti-inflammatory compounds, all of which have been associated with a reduced risk of chronic diseases and improved overall health. This article aims to provide a comprehensive evidence-based analysis of the health benefits of olive oil, which olive oil is best, and how to incorporate it into our everyday lives.

Which is the healthiest type of olive oil?

Olive oil is available in several different types, each of which varies in terms of its processing methods, flavour profile, chemical composition, and nutritional content (1). The different types of olive oil are primarily categorised based on their extraction process and quality standards. These different extraction methods alter the oil's chemical composition in different ways. The general rule is that the more refined the oil is, the more valuable compounds, such as polyphenols, vitamins, phytosterols, and other naturally occurring substances, are removed from the oil. Here is a brief overview of the different types of olive oil you will find in the supermarket:

Extra virgin olive oil (EVOO)

Extra virgin olive oil is considered the healthiest, highest quality, and most flavourful type of olive oil. To be labelled as “extra virgin” olive oil must meet strict flavour and acidity criteria accordingly, EVOO has the lowest acidity levels of all olive oils and is free from defects in flavour and aroma. Any oil labelled “virgin” must be obtained by means that do not lead to alterations in the oil (2). This is usually using treatments such as washing, decantation, centrifugation, and filtration. 

Virgin olive oil

Virgin olive oils are judged by the same criteria as EVOO however, the minimum gradings are not as restrictive as those of EVOO. Accordingly, virgin olive oils are not as flavourful and have slightly higher acidity levels.

Pure olive oil

Pure olive oil, sometimes labelled as "olive oil" "light olive oil" or “classic olive oil”, is a blend of refined olive oil and virgin or extra virgin olive oil (a usually much lesser amount). Any olive oil that does not pass the “virgin standards” is refined with heat and/or chemicals to remove undesirable odours and flavours. The resulting product is blended with a small amount of virgin olive oil to give it some olive oil character. It is a popular all-purpose cooking oil because of its higher smoke point and a more neutral flavour than virgin oils.

Why is extra virgin olive oil so healthy?

Olive oil is predominantly composed of monounsaturated fatty acids. Oleic acid is the primary fatty acid (55–83 g/100g), and it also contains small amounts of saturated and polyunsaturated fats (3). Oleic acid is associated with a reduced risk of coronary heart disease (4). EVOO is also rich in antioxidants, including tocopherols, polyphenols, and carotenoids, which contribute to its unique flavour and health-promoting properties. While other olive oils do sometimes contain these compounds, they are often not in high enough concentrations to be of benefit to the health, or they are removed altogether during the refining process (4).

What are the health benefits of olive oil?

The health-promoting effects of EVOO are largely attributed to its anti-inflammatory and antioxidant compounds. These key attributes are widely acknowledged for their role in supporting overall well-being (3). Chronic inflammation is associated with the development of various diseases, including cardiovascular disease metabolic disorders, and cancer. Olive oil contains anti-inflammatory compounds, such as oleocanthal and oleuropein, which have been shown to inhibit inflammatory pathways in the body. Oxidative stress is implicated in the aging process and the development of chronic diseases, such as cancer and cardiovascular disease. The antioxidants found in olive oil, including polyphenols and vitamin E, help protect cells from oxidative damage caused by free radicals.

More specifically, a diet rich in EVOO is associated with a decreased risk of a range of diseases including, cardiovascular disease (5), type 2 diabetes (6,7) metabolic syndrome (8,7), declines in cognitive function (9), and reductions in the risk of breast (10,11,12,13) and colorectal cancers (14,15). EVOO has also been associated with reducing all-cause mortality (16).

Cardiovascular health

EVOO has already been widely studied for its potential to prevent cardiovascular disease. A recent review found that EVOO was effective in reducing LDL-cholesterol, systolic blood pressure, oxidised LDL-cholesterol levels, total cholesterol, and increasing HDL (“good”) cholesterol (17,18). EVOO’s effect on controlling blood pressure has been observed in both those with high blood pressure, and those with blood pressure within the typical range (3).

Cognitive function and disease

Emerging research suggests that olive oil may have beneficial effects on cognitive function and brain health. A positive correlation has been found between the intake of olive oil and improved cognitive functioning among elderly adults, specifically better visual memory, and verbal fluency (19). Additionally, regular olive oil intake has the potential to lower the risk of cognitive decline over time (20). The results of in vitro and in vivo studies indicate that the regular intake of EVOO may have a neuroprotective effect and could positively prevent the development of dementia, and Alzheimer’s disease (19,21). 

Cancer

Olive oil demonstrates multiple chemopreventives including inhibition of tumour progression, abnormal cell proliferation, and amplified apoptosis (22). A recent review found that olive oil consumption was associated with a 31% lower likelihood of developing any cancer (23). When looking into specific cancers, olive oil intake seems to have the most marked risk reduction for breast cancer (22,23). A protective effect has also been found against gastrointestinal, upper aerodigestive, and urinary tract cancer (23).

Digestive health

There is a growing body of evidence supporting the positive effect consuming EVOO can have on the gut microbiota, and intestinal health (24). Extra-virgin olive oil affects the gut microbiota by reducing the abundance of pathogenic bacteria, stimulating the growth of beneficial bacteria, and increasing the gut’s production of short-chain fatty acids, which have a wide range of systemic anti-inflammatory effects (24). It also promotes a richer biodiversity of favourable gut microbiota (25). Oleic acid (the most predominant fatty acid in EVOO) also protects the intestinal which helps in preventing ulcers (26).

This article provides an excellent overview of what is known about the health benefits of EVOO:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6770785

How should I use EVOO?

The good news is EVOO can replace most other oils in your cupboard. Extra virgin olive oil has a smoke point between 175 – 210 Celsius (350 – 410F) (27) which is below the temperatures usually reached when roasting, sautéing, stir-frying, and deep-frying (at lower temperatures). This video experiments with cooking with EVOO while continuously checking the food and pan temperatures to demonstrate that the smoke point is not exceeded (27). Additionally, recent research found EVOO to be the safest and most stable oil to cook with. (28/)

While heating EVOO will affect its nutrient composition, it has been found that olive oil still retains large amounts of its healthy compounds. One study found that heat reduces the number of polyphenols in EVOO, but antioxidant and polyphenol numbers remained quite high when heated. (29). To maintain the maximum amount of nutrients, EVOO can also be added to food after cooking. For example:

• In dressings

• Drizzling over salads, vegetables, and grilled meats for added flavour

• Use as a dip for bread or to enhance the taste of cheese and antipasti platters

• Finish dishes such as pasta, soups, and grilled seafood with a drizzle to enhance their taste

A note on EVOO vs. avocado oil

Avocado oil seems to be the latest fad in the nutrition field. Even when discussing EVOO in the context of this article with my significant other he stated, “What about avocado oil, that’s meant to be better”. Avocado oil does have a similar nutritional profile as EVOO, so appears to be promising in terms of its health benefits. However, as I looked into this claim, the reality is there just isn’t enough information to say that it’s “better” or “worse” than, or even the same as EVOO. Here’s why:

1. A large chunk of the existing research on EVOO comes from decades of observational studies of people who follow the Mediterranean diet (and often have done so for many years of their lives). However, with avocado oil being relatively new on the scene, the body of evidence isn’t there to make conclusive health claims one way or another.

2. There are no internationally defined parameters for categorising avocado oil (like there are with olive oil). This means the quality could be highly variable depending on the processing methods used.

3. The smoking point of EVOO vs. avocado oil is often mis-compared. It is true that refined avocado oil has a higher smoking point than EVOO (around 270 Celsius). However, like with refined olive oils, is likely many of the health-promoting compounds have been removed or reduced in refined avocado oil.

In summary

In conclusion, olive oil, especially extra virgin olive oil, is a nutritional, versatile fat with a rich composition of monounsaturated fats, antioxidants, and anti-inflammatory compounds. EVOO's extensive health benefits range from supporting cardiovascular health and reducing chronic disease risks to aiding cognitive function and digestive health. Its versatility in culinary applications makes it an easy addition to various dishes, from salads to cooking methods like roasting and sautéing. While other oils, like avocado oil, may offer similar qualities, the extensive research and long-standing reputation of EVOO makes it a standout choice. Incorporating EVOO into your diet as part of a balanced and healthy lifestyle has great potential to improve overall health and well-being.

*Disclaimer*

The information presented in this article is for educational purposes only and is based on our interpretation of the current research. No content on this site should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

References

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