Fatty Acids in Olive Oil: What You Should Know

Olive oil is predominantly a monounsaturated fat, and its main fatty acid is oleic acid, an omega 9 monounsaturated fatty acid.

Under current International Olive Council and European compositional criteria, oleic acid accounts for 55 to 85% of the total fatty acids in olive oil. Olive oil also contains linoleic acid, an omega 6 polyunsaturated fatty acid, palmitic and stearic acids, which are saturated fatty acids, and a much smaller amount of alpha linolenic acid, an omega 3 fatty acid.

This fatty acid profile is one of the defining chemical characteristics of olive oil. It influences its nutritional composition, oxidative stability and behaviour during storage and cooking.

It is also important not to confuse the fatty acid composition of olive oil with its free acidity. Although both involve fatty acids, they measure completely different things. We explain that distinction later in this guide.

What Fats Are in Olive Oil?

Olive oil contains a mixture of monounsaturated, polyunsaturated and saturated fatty acids. It is described as predominantly monounsaturated because oleic acid represents by far the largest individual part of its fatty acid profile.

The table below summarises the principal fatty acids and the compositional ranges specified in current olive oil standards. These percentages describe the relative fatty acid composition of the oil. They should not be confused with the grams of total fat shown on a nutrition label.

These figures are based on recognised olive oil purity criteria used by the International Olive Council and European olive oil legislation.

There is one technical qualification concerning alpha linolenic acid. The standard limit is 1.00%, but edible virgin olive oil with a value above 1.00% and up to 1.40% can still be considered authentic when a specified sterol ratio and the other purity criteria comply with the standard.

The ranges are therefore compositional criteria rather than a recipe that every olive oil follows exactly. Two authentic extra virgin olive oils can have noticeably different fatty acid profiles while both conforming to recognised standards.

What Are Fatty Acids?

Fatty acids are fundamental components of dietary fats.

In olive oil, most fatty acids are incorporated into triacylglycerols, commonly called triglycerides. A triglyceride consists of a glycerol molecule attached to three fatty acids.

Triglycerides and their fatty acids make up the overwhelming majority of extra virgin olive oil. A much smaller fraction contains compounds such as sterols, tocopherols, squalene, pigments and phenolic compounds.

These minor compounds are present in far smaller quantities, but they can still contribute significantly to the sensory characteristics and oxidative stability of extra virgin olive oil. You can explore one important group in our guide to polyphenols in olive oil.

Fatty acids are commonly divided into three broad nutritional groups according to their molecular structure.

Saturated fatty acids

Saturated fatty acids contain no carbon to carbon double bonds. In olive oil, the main saturated fatty acids are palmitic acid and stearic acid.

Monounsaturated fatty acids

Monounsaturated fatty acids, often shortened to MUFAs, contain one carbon to carbon double bond. Oleic acid is the dominant monounsaturated fatty acid in olive oil.

Polyunsaturated fatty acids

Polyunsaturated fatty acids, often shortened to PUFAs, contain two or more carbon to carbon double bonds. The principal examples in olive oil are linoleic acid, an omega 6 fatty acid, and alpha linolenic acid, an omega 3 fatty acid.

The number and position of these double bonds help determine how a fatty acid is classified and also influence its susceptibility to oxidation.

Is Olive Oil Monounsaturated?

Yes. Olive oil is predominantly monounsaturated.

The main reason is its high concentration of oleic acid. Current olive oil standards specify that oleic acid can account for 55 to 85% of total fatty acids.

Olive oil also contains smaller quantities of other monounsaturated fatty acids, particularly palmitoleic acid and eicosenoic acid.

This distinction matters when asking what percentage of olive oil is monounsaturated. The official 55 to 85% range applies specifically to oleic acid, not to total monounsaturated fatty acids. Total MUFA content also includes the smaller monounsaturated fatty acids and can therefore be slightly higher than the oleic acid percentage alone.

The NHS guidance on dietary fats also identifies olive oil as a source of monounsaturated fat and recommends replacing some saturated fats with unsaturated fats as part of a balanced diet.

If the question is simply “What type of fat is olive oil?”, the clearest answer is:

Olive oil is an unsaturated fat composed predominantly of monounsaturated fatty acids, with oleic acid as its main fatty acid.

Oleic Acid: The Main Fatty Acid in Olive Oil

Oleic acid is the principal fatty acid in olive oil.

Its chemical notation is C18:1. This means that it contains 18 carbon atoms and one carbon to carbon double bond. It is a monounsaturated fatty acid belonging to the omega 9 family.

The predominance of oleic acid is one of the most recognisable characteristics of the olive oil fatty acid profile.

Its structure is also relevant to stability. Oleic acid contains one double bond, while linoleic acid contains two and alpha linolenic acid contains three. In general, increasing the number of double bonds increases susceptibility to oxidative reactions.

The high proportion of oleic acid therefore contributes to the oxidative stability of olive oil. The final stability of an extra virgin olive oil also depends on its antioxidant compounds, exposure to oxygen and light, storage temperature and the conditions in which it is used.

Does Olive Oil Contain Polyunsaturated Fat?

Yes. Olive oil contains polyunsaturated fat, although polyunsaturated fatty acids normally represent a smaller proportion of its fatty acid profile than monounsaturated fatty acids.

The two principal polyunsaturated fatty acids in olive oil are linoleic acid and alpha linolenic acid.

Linoleic acid belongs to the omega 6 family. Alpha linolenic acid belongs to the omega 3 family. Both are essential fatty acids because the human body cannot produce sufficient quantities of them and they need to be obtained from the diet.

How much linoleic acid is in olive oil?

Linoleic acid is the principal omega 6 fatty acid in olive oil.

Its chemical notation is C18:2 because it contains 18 carbon atoms and two carbon to carbon double bonds. Recognised olive oil standards specify a range of 2.5 to 21% of total fatty acids.

The width of this range shows why the fatty acid composition of olive oil should not be treated as fixed. Cultivar, environmental conditions and fruit maturity can all influence the relationship between oleic and linoleic acid.

Does Olive Oil Have Omega 3?

Yes. Olive oil contains omega 3, but only in a relatively small quantity.

The principal omega 3 fatty acid in olive oil is alpha linolenic acid, usually abbreviated to ALA and identified chemically as C18:3.

The standard compositional limit is normally no more than 1.00% of total fatty acids, subject to the specific authenticity provision described earlier for some edible virgin olive oils with levels between 1.00 and 1.40%.

Olive oil should therefore not be regarded as a major source of omega 3. Its fatty acid profile is dominated by omega 9 oleic acid. Omega 6 linoleic acid forms a smaller proportion, while omega 3 alpha linolenic acid is present only in modest amounts.

Omega 3, omega 6 and omega 9 are names for families of unsaturated fatty acids. They are not grades or quality classifications of olive oil.

Does Olive Oil Contain Saturated Fat?

Yes. Olive oil is predominantly unsaturated, but it is not free from saturated fat.

The main saturated fatty acids in olive oil are palmitic acid and stearic acid. Current compositional criteria specify approximately 7 to 20% palmitic acid and 0.5 to 5% stearic acid.

This illustrates an important point about dietary fats. Oils and foods generally contain mixtures of different fatty acids rather than belonging exclusively to one category.

Olive oil contains saturated, monounsaturated and polyunsaturated fatty acids, but monounsaturated fatty acids predominate.

What Other Fatty Acids Are Found in Olive Oil?

Oleic, linoleic, palmitic and stearic acids account for most of the fatty acid profile, but olive oil also contains several fatty acids at much lower concentrations.

These include palmitoleic acid, heptadecanoic acid, heptadecenoic acid, arachidic acid, eicosenoic acid, behenic acid and lignoceric acid.

Although individually present in small amounts, these compounds contribute to the overall chemical fingerprint of olive oil.

Fatty acid composition is therefore useful for more than nutritional description. It forms part of the purity and identity criteria used in official olive oil analysis. Laboratories assess the complete fatty acid profile alongside other measurements when determining whether an oil conforms to recognised olive oil standards.

Do All Olive Oils Have the Same Fatty Acid Profile?

No. The broad pattern is characteristic of olive oil, but the precise proportions can vary considerably.

Olive cultivar is important because different varieties have different genetic characteristics that influence fatty acid composition.

Growing region and climate also matter. Temperature and other environmental conditions affect fruit development and fatty acid biosynthesis.

Fruit maturity can influence the profile as well because fatty acid composition changes during olive development and ripening.

Research comparing virgin olive oils from different cultivars confirms that the cultivar can substantially influence the balance of major fatty acids such as oleic and linoleic acid.

This is one reason origin is more than a geographical name on a label. Our guide to olive oil regions and how origin shapes taste and quality explores how climate, location and growing conditions contribute to the character of an olive oil.

What About Koroneiki Olive Oil?

Koroneiki is one of the best known Greek olive cultivars and is particularly associated with olive oil production in Greece and Crete.

A study examining 199 virgin olive oil samples from four widespread Greek cultivars found significant differences in fatty acid composition between cultivars. In that study, Koroneiki had the lowest average linoleic acid concentration among the four cultivars examined, illustrating how strongly cultivar can influence the fatty acid profile.

The precise composition of a Koroneiki oil is not fixed, however. Growing conditions, geographical location, season and fruit maturity can still alter the final profile.

The cultivar name should therefore not be interpreted as a guarantee of one particular oleic acid percentage.

Euthis is produced exclusively from Koroneiki olives grown in Crete. You can learn more about the relationship between the variety and its environment in our guide to why Crete is famous for olive oil.

Why Does Fatty Acid Composition Affect Oxidative Stability?

Oxidation is one of the principal processes through which oils gradually deteriorate.

Fatty acid structure affects how readily oxidation occurs. Oleic acid contains one double bond, linoleic acid contains two and alpha linolenic acid contains three.

Polyunsaturated fatty acids are generally more susceptible to oxidation than monounsaturated fatty acids. The high proportion of monounsaturated oleic acid therefore contributes to the oxidative stability associated with olive oil.

The fatty acid profile is only one part of the picture. Extra virgin olive oil also contains naturally occurring minor compounds, including phenolic compounds and tocopherols, which can contribute to oxidative stability.

Storage time, temperature, oxygen and exposure to light also affect how quickly an oil changes. For this reason, fatty acid composition should never be interpreted as a complete measure of stability by itself.

Our separate guide explains what polyphenols in olive oil are and why they matter.

What Happens to Olive Oil Fatty Acids During Cooking?

Heating promotes chemical reactions in all cooking fats. The extent of those changes depends on temperature, heating time, oxygen exposure, fatty acid composition and the presence of antioxidant compounds.

The high proportion of monounsaturated oleic acid contributes to the oxidative stability of olive oil compared with oils containing much larger proportions of polyunsaturated fatty acids.

Extra virgin olive oil also contains naturally occurring phenolic compounds and tocopherols. Research on cooking and heating shows that some of these compounds gradually decline as temperature and heating time increase, although the extent varies considerably according to the conditions used.

Ordinary cooking should therefore be distinguished from prolonged or repeated high temperature heating. Temperature, time and repeated exposure all influence oil deterioration.

For practical information about sautéing, frying, roasting, baking and using olive oil uncooked, see our complete guide to cooking with extra virgin olive oil.

Why Does Olive Oil Change During Storage?

Olive oil gradually changes after production. Unlike wine, it does not improve simply by becoming older.

Oxygen, heat and light accelerate oxidative reactions. Over time, these processes can reduce freshness, alter aroma and flavour, and contribute to the degradation of naturally occurring antioxidant compounds.

Packaging and storage therefore matter. Dark glass bottles and metal tins help protect olive oil from light, while keeping a container properly closed reduces unnecessary exposure to oxygen.

Handling before packaging is also important. Our guide to how organic extra virgin olive oil is made explains how harvesting, milling, extraction and storage contribute to the finished oil.

Is the Fatty Acid Profile the Same Thing as Olive Oil Quality?

No. Fatty acid composition provides important chemical information, but it is not a complete measure of olive oil quality.

The fatty acid profile forms part of the identity and purity criteria used to assess whether an oil is chemically consistent with olive oil.

Qualifying as extra virgin olive oil requires more than having the correct fatty acid composition.

Under the current International Olive Council standard, extra virgin olive oil has free acidity of no more than 0.80 grams per 100 grams, expressed as oleic acid, and must also comply with other physicochemical and organoleptic criteria.

An oil can therefore have a fatty acid profile consistent with genuine olive oil and still fail to meet the requirements for the extra virgin category because of another analytical parameter or a sensory defect.

This is why olive oil quality should never be judged from a single laboratory figure.

What Is the Difference Between Fatty Acids and Olive Oil Acidity?

This is one of the most common sources of confusion when discussing olive oil.

The fatty acid profile describes which fatty acids are present and their relative proportions.

Free acidity measures fatty acids that have been released from triglycerides rather than remaining bound within them.

For example, an olive oil containing a high percentage of oleic acid does not therefore have high free acidity.

The phrase “expressed as oleic acid” in an acidity result is a convention used to report the measurement. It does not mean that all of the oleic acid naturally present in the triglycerides is being counted as free acidity.

This distinction is explained in much greater detail in our guide to olive oil acidity and what it really means.

What Is the Difference Between Fatty Acids and Polyphenols?

Fatty acids and polyphenols belong to very different parts of olive oil chemistry.

Fatty acids form the structural basis of the triglycerides that make up almost all of the oil.

Polyphenols are minor compounds present at far lower concentrations. Despite their small quantity, they can contribute to bitterness, pungency and oxidative stability.

A high oleic acid percentage does not automatically mean that an olive oil has a high polyphenol concentration. Likewise, knowing an oil’s polyphenol content does not reveal its exact fatty acid composition.

Olive cultivar, environment, harvest timing, processing and storage can affect these characteristics in different ways.

For a detailed explanation, read our guide to polyphenols in extra virgin olive oil.

Does Organic Olive Oil Have a Different Fatty Acid Profile?

Not necessarily.

Organic certification relates to the agricultural production and controlled handling system used to produce the olives and olive oil. It does not define a special fatty acid composition that every organic olive oil must have.

Fatty acid composition is influenced by factors including olive cultivar, climate, growing region and fruit maturity.

Organic certification should therefore not be interpreted as a guarantee of a particular oleic acid percentage, polyphenol concentration or flavour profile.

Our separate guide explains what organic olive oil means and how certification works.

What Does the Fatty Acid Profile Tell You When Choosing Olive Oil?

Fatty acid composition tells us a great deal about the chemistry and identity of olive oil, but consumers rarely see a complete fatty acid analysis on the label.

When choosing an extra virgin olive oil, it is more useful to consider several characteristics together. These include the category of oil, provenance, olive variety, production method, freshness, packaging, storage conditions, available analytical information and sensory character.

No single percentage provides a complete measure of quality.

Our guide to choosing a good extra virgin olive oil explains how these different factors fit together.

Frequently Asked Questions About Fatty Acids in Olive Oil

What type of fat is olive oil?

Olive oil is predominantly an unsaturated fat. Most of its fatty acids are monounsaturated, with oleic acid forming the largest individual component.

Is olive oil monounsaturated or polyunsaturated?

Olive oil contains both, but it is predominantly monounsaturated. Oleic acid is the main monounsaturated fatty acid, while linoleic acid and alpha linolenic acid form the principal polyunsaturated fraction.

What percentage of olive oil is monounsaturated?

There is no single percentage for every olive oil. Oleic acid alone can account for 55 to 85% of total fatty acids. Total monounsaturated fat can be slightly higher because olive oil also contains smaller amounts of other monounsaturated fatty acids.

What is the main fatty acid in olive oil?

The main fatty acid is oleic acid, also known as C18:1. It is a monounsaturated omega 9 fatty acid.

Does olive oil contain linoleic acid?

Yes. Linoleic acid is the principal omega 6 polyunsaturated fatty acid in olive oil. Recognised compositional criteria specify a range of 2.5 to 21% of total fatty acids.

Does olive oil contain omega 3?

Yes. Olive oil contains the omega 3 fatty acid alpha linolenic acid, but usually in a small amount. The standard compositional limit is normally no more than 1.00%, with a specific authenticity exception for some edible virgin olive oils between 1.00 and 1.40% when additional criteria are satisfied.

Does olive oil contain omega 6?

Yes. Linoleic acid is the principal omega 6 fatty acid in olive oil and can represent approximately 2.5 to 21% of its total fatty acid composition.

Does olive oil contain saturated fat?

Yes. Olive oil contains saturated fatty acids, principally palmitic and stearic acid, but unsaturated fatty acids make up the majority of its fatty acid profile.

Is oleic acid the same as olive oil acidity?

No. Oleic acid is the main fatty acid naturally present in olive oil. Free acidity measures fatty acids that have been released from triglycerides. A high proportion of oleic acid does not mean an olive oil has high free acidity.

Do all olive oils contain the same amount of oleic acid?

No. Oleic acid concentration varies naturally. Olive cultivar, climate, geographical environment and fruit maturity can all affect the final fatty acid composition.

Summary

Olive oil is predominantly a monounsaturated fat, and oleic acid is its most abundant fatty acid.

Current olive oil compositional standards specify 55 to 85% oleic acid, 2.5 to 21% linoleic acid, 7 to 20% palmitic acid, 0.5 to 5% stearic acid and normally no more than 1.00% alpha linolenic acid, subject to a specific authenticity provision for certain edible virgin olive oils.

Olive oil therefore contains omega 9, omega 6 and omega 3 fatty acids, but in very different proportions. Omega 9 oleic acid dominates the profile, while omega 6 linoleic acid is present in smaller quantities and omega 3 alpha linolenic acid represents only a minor fraction.

The exact profile varies according to factors including olive cultivar, environment and fruit maturity. These natural differences are one reason authentic olive oils from different cultivars and regions can have distinct chemical characteristics.

Fatty acid composition also contributes to oxidative stability and provides important information about olive oil identity and purity. It does not, however, determine olive oil quality by itself. Extra virgin classification depends on a wider combination of physicochemical and sensory criteria.

Understanding fatty acids therefore provides an important foundation for understanding olive oil, but it is one part of a much larger picture.

Sources and Further Reading

The compositional ranges and technical information in this guide are based on recognised olive oil standards and scientific literature. Readers who would like to explore the subject in greater detail can consult the following sources.

• International Olive Council: Standards, Methods and Guides
• European Union: characteristics of olive oil and olive pomace oil
• NHS: Different fats and nutrition
• Bioactive Compounds and Quality of Extra Virgin Olive Oil
• Chemometric Study of Fatty Acid Composition of Virgin Olive Oil from Four Widespread Greek Cultivars
• A Review of the Effects of Olive Oil Cooking on Phenolic Compounds