When it comes to oils for cooking and for our meals, there is no shortage of choices out there. After all, there are many different types of oils as well as some products with added ingredients that are supposed to make them healthier (like omega-3 fatty acids).
But, all of those options can just make the process of choosing a healthy oil just that much more difficult.
Olive oil has quickly developed a reputation as being a healthy option, but just what benefits does the oil actually offer? For that matter, is it actually worth the price tag and is olive oil good for you?
In this post, we’re going to look at the science behind olive oil and the health benefits associated with it.
Research into the Health Benefits of Olive Oil
Understanding the research into olive oil can be a little challenging because there have been so many different types of studies out there. For example, some studies have looked at olive oil as an addition to the diet while others have looked at healthy diet types that contain olive oil (particularly the Mediterranean diet). Likewise, the participants of such studies have varied widely.
To make matters even more complex, studies can also vary in the way that they define specific grades of olive oil (like extra virgin olive oil) and how much effort they take to ensure that the grade of the oil matches up to what it actually contains. This means that more reliable approaches to research and testing are needed before we can completely understand the health benefits of extra virgin olive oil and olive oil in general (1).
However, despite this issue, we can use the information from research to get an overall indication of the benefits that olive oil offers and why it is good for health.
A lot of the research into olive oil and health benefits has looked at olive oil specifically, often using either extra virgin olive oil or just virgin olive oil. However, there have been some variations.
For example, within olive oil, there are a few specific compounds that have been associated with observed health benefits. These include the compounds oleocanthal, hydroxytyrosol, tyrosol and oleuropein, all of which are phenols (2). Some research studies have considered the impacts of these phenols or of just one specific compound.
Heart Disease Risk
Heart disease is a major issue in modern society. While we cannot entirely prevent heart disease, we can reduce risk by reducing risk factors for the disease. Research has shown that olive oil can play a role in reducing a range of risk factors (3,4).
One study showed that polyphenols from olive oil could decrease LDL concentration and LDL atherogenicity in males. Both of these areas are considered to be risk factors for heart disease development and LDL atherogenicity is a measure of the number of small LDL particles (the dangerous ones) and how easily the LDL can be oxidized (5). As such, the outcomes of the study support the idea that compounds from olive oil can potentially decrease heart disease risk.
Another study indicated that the use of extra virgin olive oil was able to decrease blood glucose levels following a meal as well as LDL cholesterol levels (6).
Research also shows that the polyphenols can increase the function of HDL (the ‘good’ cholesterol), which also has the potential to decrease heart disease risk (7,8,9). Likewise, olive oil can increase the level of HDL while decreasing oxidative stress (10,11).
A meta-analysis also found an association between olive oil consumption and improvement in endothelial function (12). This is an important area as endothelial dysfunction has been associated with heart disease risk (13,14).
Research has also indicated that the phenolic compounds in olive oil play a role in the expression of some genes related to blood pressure and can help to decrease blood pressure (15).
The benefits of olive oil aren’t just limited to the risk factors for heart disease.
One study looked at the consumption of virgin olive oil in individuals at high risk for heart disease. The authors found that higher levels of olive oil consumption were associated with decreased mortality in participants. Additionally, risk factors for heart disease were also lower with higher levels of olive oil consumption (16).
Likewise, one study found that that consumption of olive oil had a protective effect against coronary artery disease in humans (17).
Olive Oil and Inflammation
One of the health benefits often associated with olive oil is the ability to fight inflammation. Inflammation is our body’s response to various invaders but often inflammation occurs when it isn’t needed. To make matters worse, inflammation has been connected to the development of various diseases (18,19,20). As such, decreasing inflammation may be a key way to promote overall health and reduce disease risk (21).
Olive oil is especially relevant when it comes to inflammation because of a compound called oleocanthal. This compound has anti-inflammatory properties and shares some characteristics with Ibuprofen, which is also used to fight inflammation and the pain associated with inflammation (22, 23).
A systematic review of the topic also concluded that olive oil may play a key role in fighting inflammation.
However, the authors did note that the research into this topic has involved a wide variety of designs, so more research is needed to confirm the results (24).
Researchers argue that the presence of oleocanthal and its actions in the body may be a key reason why the Mediterranean diet is so healthy (28,29). Likewise, a Mediterranean diet may be a particularly effective way of combating inflammation and disease (30,31).
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Fighting Aging Through Antioxidants
The modern diet contains many components that promote aging, particularly unhealthy aging. Reducing inflammation and oxidation are two approaches that are often promoted as a way of fighting aging.
Polyphenols, like those in olive oil and also cocoa, play a key role in fighting oxidation (32). Indeed, some researchers suggest that extra virgin olive oil may play a role in fighting diseases related to aging (33,34). However, more research is needed to determine whether this effect is significant in humans and what mechanisms underlie any outcomes (35).
One study looked at the impact that extra virgin olive oil had on aging in rats, including life length and oxidative damage to DNA. Those rats were also placed on a high-calorie diet, which helped to mimic some of the impacts of our modern diet.
The authors found that the olive oil did not prevent weight gain but it did play a key role in fighting oxidation (36).
Another animal study found that extra virgin olive oil played an antioxidant role and the observed results suggested that the olive oil might also have an anxiety-lowering effect (37).
A similar study also indicated that phenols from olive oil decreased inflammation and oxidative stress. The study also found that the phenols improved contextual memory in young animals and prevented age-related motor function impairment (38).
The compound hydroxytyrosol is partly responsible for this antioxidant function, as it has the ability to protect against oxidative stress and DNA damage (39,40). Another antioxidant in olive oil is tyrosol. While this compound does not have as strong impacts as hydroxytyrosol it does still play a key role in protecting against oxidative damage (41,42).
Impacts on Cancer
Olive oil, particularly the extra virgin olive oil, has also been linked to the ability to fight cancer.
One key reason for this effect is the compound oleocanthal, which is the same compound that was linked to anti-inflammatory effects. Research suggests that this compound can help promote the death of cancer cells without affecting healthy cells (43).
At the same time, oleocanthal is interesting because it causes that cell death through an action called lysosomal membrane permeabilization. This is a novel approach and suggests an alternative direction for therapies that target cancer (44).
Another compound in olive oil that might contribute to this action is hydroxytyrosol (45). One reason for this action is the potential for hydroxytyrosol to protect against oxidative damage to human DNA (46). The compound has also been linked to promoting apoptosis (programmed cell death) in human colon (47) and prostate cancer cells (48).
Research also suggests that olive oil’s ability to fight inflammation may also help it to reduce the risk of cancer (49).
One interesting study looked at supplementation with olive oil in participants who were in one of three sample groups:
- Mediterranean diet with additional extra virgin olive oil
- Mediterranean diet with additional nuts
- Control diet with advice to decrease fat intake
Participants followed the diet in the study for an average of 4.8 years, which is an extremely long time for an experimental study. The authors found that the rates of breast cancer among the sample were 1.1 for the Mediterranean diet with olive oil, 1.8 for the Mediterranean diet with nut group and 2.9 for the control group (50).
These results mean that the group that followed the Mediterranean diet with olive oil had the lowest rate of breast cancer while the control group had the highest rate.
Those outcomes promote two conclusions.
The first is that the Mediterranean diet itself is healthy and can be a way to decrease the risk of breast cancer. The second conclusion is that extra virgin olive oil can play a role in decreasing breast cancer risk.
Another study proposed a potential mechanism for how a polyphenol from extra virgin olive oil could fight tumors in colon cancer (51).
So, is olive oil good for you? Based on the studies we've looked at so far, I'd say that yes, it certainly is.
Other Benefits of Olive Oil
One study also indicated that the phenols from olive oil have the potential to interfere with some of the pathways involved in the development of Alzheimer’s disease, including in the development of amyloid-beta (Aβ) plaques (52). This action may be partially connected to the compound oleocanthal, which can help to promote the clearance of Aβ plaques (53).
Research has also suggested that higher levels of olive oil intake are associated with a decreased risk of type 2 diabetes in women (54).
Both olive oil and the Mediterranean diet have been associated with improved bone health. One animal study showed that supplementation with virgin olive oil fortified with vitamin D3 contributed to increased bone turnover and better bone mineral density (55). This outcome suggests a beneficial relationship between vitamin D and olive oil for bone health.
Another study on the topic showed that vitamin D and olive oil were able to prevent bone loss in mice (56). Additionally, research shows that the phenolic compounds in olive oil help to promote the development of osteblastic cells, which play a key role in bone development (57).
Research suggests that virgin olive oil and its components can act as an antioxidant and anti-inflammatory agent, while also helping to decrease heart disease risk and even fight both aging and cancer.
Types of Olive Oil
As you’ve probably noticed, there is a range of different variants of olive oil. These range in price and also in quality. Many of these types are also international grades of olive oil, although these grades can be difficult to regulate.
The undisputed king of olive oil is the extra virgin olive oil. This type of olive oil is obtained from the first pressing of an olive harvest.
At the same time, extra virgin olive oil has to meet a certain level of quality, including having a relatively low level of acidity and containing no sensory defects.
This process means that the oil is very high quality and doesn’t involve any additives at all. Of course, this does also make extra virgin olive oil fairly expensive. The process of making extra virgin olive oil also means that the oil is likely to have the most health benefits. In fact, many of the research studies considered above specifically focus on extra virgin olive oil.
So, if you’re wanting the most health benefits from olive oil, extra virgin olive oil is the best way to go.
In general, the term ‘virgin’ in relation to olive oil means that the oil has been extracted without the use of chemical methods. So, virgin olive oil is essentially a lower quality version of extra virgin olive oil and is typically obtained from the second press of olives.
You will also find refined olive oil.
This form of olive oil has gone through some processing. While the overall chemical structure of the oil is unchanged, the process removes the flavor, color and odor of the olive oil. This means that the health benefits of this type of oil are also likely to be fewer.
You will often find that olive oils contain a combination of these types.
For example, an oil might use some virgin olive oil to give the desired taste but may also contain some refined olive oil. That approach is typically less expensive for companies to create and many consumers might not even be able to tell the difference. However, the difference in health benefits is likely to be significant.
It’s worth noting that the United States does not follow the international standards for olive oil grades, although the USDA does have grades for olive oil. These grades specifically focus on the quality of the oil rather than whether it was obtained in the first or subsequent pressing (58).
In general, these differences suggest that people should look towards extra virgin olive oil for the best health benefits – although virgin olive oil may be a good second choice for people that cannot afford the extra virgin option. In contrast, refined oils tend to have a lower phenolic content (59).
However, as I’ll discuss below, the labels on olive oil can be extremely misleading and often you don’t actually get what you are paying for.
Out of the different types of olive oil, extra virgin olive oil is the least processed followed by virgin olive oil. Realistically, you need to choose one of these two types if you want health benefits from olive oil.
Buying Good Quality Olive Oil
Without a doubt, extra virgin olive oil is the way to go if you want to get the most benefits out of your olive oil. However, extra virgin olive oil often doesn’t end up being nearly as good as you might expect.
One of the biggest issues is that most commercial extra virgin olive oil is adulterated in some way. In general, that term means that something has been added into the product to lower its quality.
When it comes to olive oil, some estimates suggest that as much as 80% of the extra virgin olive oil sold in the United States doesn’t meet the legal requirements for extra virgin olive oil.
In many cases, this happens because manufacturers mix in other types of olive oil in with the extra virgin. However, in some cases, you might not even end up with olive oil. Instead, it may be another type of oil that has been made to look and smell like olive oil (60).
This issue is so significant because supply chains have become complex globally. This makes it easy for companies to mislead consumers and it makes it hard to guarantee that extra virgin olive oil is actually what the bottle says.
To make matters worse, we don’t have reliable scientific approaches to accurately identify whether or not olive oil is actually extra virgin in nature (61). However, research has been developing in this area and some techniques exist for identifying specific types of adulteration, such as when sunflower or red palm oil are added into the mix (62).
One way to increase the chances of getting good olive oil is to look for extra virgin olive oil that has actually been produced in Italy. It’s particularly encouraging if the olive oil comes from a city with a reputation for producing the oil (like Sicily). Alternatively, looking for extra virgin olive oil from California may also be a good approach (63).
Some manufacturers do also sell products directly to consumers online. So, if you do find a brand you trust, this may be one way to ensure that you get the oil you want.
Additionally, you can look for the harvest date. Not all brands have this information but finding it can be particularly important. Olive oil is one product that is best when it is fresh, so older oil tends to be poor quality (64).
When it comes to olive oil, the price is another key thing.
Realistically, if you find an inexpensive bottle of olive oil, it probably isn’t very good. That’s especially true for extra virgin olive oil.
You can find one fairly reliable list of good olive oil brands at The Truth in Olive Oil but the list is far from complete and there are probably many other good brands out there.
Additionally, the post The Healthiest Olive Oil Brands You Can Buy Online can help you select a high-quality option that will truly offer health benefits.
Myths and Facts About Olive Oil Quality
With all the concern that surrounds olive oil and finding real olive oil, it shouldn’t be too surprising that there are a number of myths out there.
Color: People often say that olive oil should be green, with deeper greens being more ideal. But, this isn’t accurate and good quality olive oil can come in a wide range of colors, including versions of olive oil that are closer to yellow than to green.
Purchase Location: In theory, buying olive oil from a reputable store (like a health food store) should mean you get unadulterated oil. Unfortunately, there are no guarantees and food stores can get mislead by manufacturers just like the rest of us. After all, modified olive oil does pass most tests and this makes it extremely difficult to identify.
Taste: The taste of olive oil is partly connected to the time of harvest, the specific olives used and other factors. This means that, despite popular belief, real olive oil does not have to be bitter. Instead, late season olives tend to produce a fairly mild, almost sweet, flavor.
Solidifying: Some people claim that you can test whether olive oil is extra virgin by whether it solidifies in your fridge, suggesting that real extra virgin olive oil should solidify while fake stuff shouldn’t. This isn’t true. Instead, you will find variation between one brand and the next. At the same time, companies that adulterate their oils will sometimes pick their ingredients carefully to make it solidify.
Labels on olive oil often aren't accurate and it can be difficult to find extra virgin olive oil, especially as many of the assumptions that people make about oil quality aren't true
Other Things to Consider
Cooking with Olive Oil
Olive oil (particularly extra virgin olive oil) is often viewed as a great ingredient but not something that you should be using for cooking. However, research suggests that this idea isn’t accurate.
In general, whether or not you should cook with a given oil comes from what happens when they are exposed to high heat. At high heat, oils can produce a range of harmful compounds, including some that may contribute to cancer (65,66). This effect is particularly strong in oils that have high levels of polyunsaturated fats.
This means that you want to be looking for fats and oils that are fairly stable even at high heat. Two pieces of information can help you to determine this, the smoke point and the oxidative stability.
Olive oil actually ends up being a good oil for cooking, because it is high in monounsaturated fats. This type of fat tends to be pretty stable during cooking and the compounds in olive oil do appear to be stable during cooking (67). At the same time, research shows that olive oil is pretty stable against oxidation (68).
This means that olive oil is unlikely to oxidize during cooking and is unlikely to produce dangerous compounds.
However, it is important to note that extended heating can decrease the activity of oleocanthal, which is a natural anti-inflammatory agent present in olive oil (69). That outcome does suggest that olive oil will be healthier when it isn’t heated.
But, even so, this does not mean that cooking with olive oil is dangerous or should be avoided. Indeed, it’s likely that the health benefits of most functional foods are going to decrease after cooking. After all, the process of heating does have significant effects on the chemical composition of food.
Storing Olive Oil
As a general rule, olive oil should be stored in a dark and cool place, as both heat and light can affect the quality of the oil. At the same time, olive oil should be kept in an airtight container, because exposure to oxygen increases the risk of oxidation (70,71). Storing olive oil in these conditions can help it to retain its taste and nutritional qualities (72).
Additionally, exposure to UV radiation can have impacts on the compounds within olive oil (including the phenols and fatty acids) and can also alter the taste of the oil (73).
But, there are some other things to consider when it comes to storing your olive oil.
For one thing, plastic is normally a poor choice. There is always a risk that some chemicals will leach out of the plastic into your olive oil. At the same time, plastic lids are often not all that effective at keeping air out of a bottle (74).
These issues may be why most high-quality olive oil brands are sold in glass bottles.
At the same time, having a colored glass container for your olive oil will tend to be more effective than one that isn’t colored. This comes back to the issue of light as a colored container will tend to let in less light than a container that is clear.
Despite common believe, you can safely cook with olive oil. Additionally, you should store your oil in a cool dark place, ideally in an airtight glass container
Is Olive Oil Good For You?
Olive oil has an extensive reputation as a healthy ingredient for the diet and the research into the oil and its effects certainly confirms this reputation. This is true for olive oil itself and also for olive oil as a component of the Mediterranean diet.
Certainly, the benefits of olive oil suggest that the oil is better for health than most other oils that you might use for cooking or in meals (although coconut oil and butter are also healthy options).
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Do you use olive oil regularly? If so, what type do you use?