The Benefits of Olive Oil
What is olive oil?
Olive oil is produced by pressing fresh olives, the fruit of the olive tree, and extracting the oil. The International Olive Council (IOC) defines olive oil as ‘oils obtained from the fruit of the olive tree solely by mechanical or other physical means under conditions, particularly thermal conditions, that do not lead to alterations in the oil, and which have not undergone any treatment other than washing, decantation, centrifugation and filtration’ (1). There is a lot of controversy surrounding the health benefits of dietary fat, however as olive oil is high in monounsaturated fats it is known for its numerous health benefits. 73% of olive oil is made up of monounsaturated fats, with only 14% being saturated fats and 11% being polyunsaturated (2).
What are the benefits of olive oil?
The health benefits of olive oil greatly depend on the grade of oil with extra virgin olive oils and virgin olive oils having more nutritional benefits. Olive oil is extremely high in antioxidants which are known to reduce the risk of chronic disease. Antioxidants are also known to reduce the risk of inflammation and protect blood cholesterol from oxidation. In addition to this olive oil contains beneficial fatty acids, as well as vitamins E and K (6).
Olive oil is also known for its powerful anti-inflammatory properties (14). Extra-virgin olive oil is particularly good at reducing inflammation which could contribute to reducing the risk of cancer, heart disease, metabolic syndrome, and type 2 diabetes. The main fatty acid in olive oil is oleic acid which contributes to its anti-inflammatory properties (6). Olive oil can have beneficial effects in reducing and preventing certain diseases. Research has found that olive oil is associated with a reduced risk of heart disease and stroke, whereas other monounsaturated fats are not (7). Another study found that consuming olive oil reduces the risk of having a stroke, when compared to not consuming it (8).
Olive oil is also known to have many beneficial properties when it comes to heart health. Due to the polyphenolic compounds of virgin olive oils, they have been known to have anti-inflammatory and antioxidative effects in cardiovascular disease (9 (15). Consuming olive oil reduces the likelihood of LDL ‘bad’ cholesterol from being oxidised and hence significantly contributes to reducing the risk of heart disease (10). High blood pressure is one of the main risk factors for heart disease. Olive oil has been known to reduce both systolic and diastolic blood pressure (11). Additionally, olive oil can have beneficial effects on brain health. One study found that when comparing a Mediterranean diet rich in olive oil to a low-fat diet, the Mediterranean diet improved brain function (12). Furthermore, higher consumptions of olive oil, when compared to lower consumptions have been seen to lower the risk of developing any type of cancer (14), as well as particularly lowering the likelihood of developing breast cancer (13).
What is the difference between the different grades of olive oil?
Not all olive oil is created equally. There are two main grades of olive oil: refined, and unrefined and within these there are different types (3). High phenolic extra virgin olive oil is the highest quality of unrefined olive oil. The freshly pressed juice is unrefined and is made from unripe green olives picked early in the season. It is a vibrant emerald, green colour and must pass the sensory and chemical tests for extra virgin oils plus a chemical analysis of polyphenol levels. For olive oil to be classed as high polyphenol it must contain polyphenol levels above 250 mg/kg. However, a daily intake of 20g of polyphenols is known to have beneficial effects for the consumer such as contributing to the protection of blood lipids from oxidative stress. This type of olive oil has a fresh grass, fruity, green olive, and spicy/peppery taste (3).
Extra virgin olive oil is a freshly pressed olive juice with the olive water removed. It must be 100% extra virgin olive oil with low acidity, no refining, no chemicals, and no heat treatment (3). This type of olive oil is also high in antioxidant polyphenols, which has been seen to slow down the development of cardiovascular and neurodegenerative diseases as well as cancer (4). Extra virgin olive has a balanced aroma, and the taste can range from mild to bitter, and from fruity to peppery (3). Virgin olive oil is relatively like extra virgin olive oil but may have slightly organoleptic defects and is mainly used to add flavour and aroma to regular olive oil (3). It is slightly lower in antioxidants and vitamins as some of these are lost during processing (5).
There are also several refined varieties of olive oil. Refined olive pomace oil is made from the by-products of extra virgin olive oil production. The remaining pulp ‘pomace’ from the stones and flesh contains a small amount of oil which is extracted with the use of chemical solvents and then refined using extremely high heat, in the same way as sunflower, canola and other vegetable oils are refined. This process results in a more acidic oil which is lacking in taste, aroma and devoid of any polyphenols. This depletes the oil of the health benefits of polyphenols (3). Refined olive oil is olive oil that doesn't meet extra virgin chemical or sensory standards and is then refined and cleaned. No solvents are used but it has been refined using high heat, high pressure, filtration, and chemicals to get rid of undesirable defects. This means that it lacks taste, aroma and polyphenols which lowers the nutritional value of the olive oil (3).
Our advice
- Small changes can make a difference! Try to use olive oil when cooking due to the high monounsaturated fat content rather than other saturated fats such as butter or polyunsaturated fats such as sunflower oil.
- If possible, try to use extra virgin olive oil as this contains the most nutrients and is known to have the most health benefits.
- Try olive oil in a variety of different ways such as for cooking, drizzling over salads or dipping for bread.
- For some delicious olive oil check out The Governor’s Extra Virgin Olive Oil (https://thegovernorevoo.co.uk)!