The Mediterranean diet is known as one of the healthiest in the world and associated with longevity and well-being. It has shown protective effects against cancer and other cardiovascular and inflammatory diseases. This diet is composed of a variety of cereals, fruits, beans, vegetables, nuts and central to all of them olive oil, and more specifically, extra virgin olive oil.
The olive oil is composed majorly of fatty acids, although it has more than 200 extra minor components. It can be found in two forms:
- Extra virgin olive oil. Obtained by pressing olives without further treatments, allowing preservation of the minor components within the oil.
- Refined olive oil. Obtained by mechanical extraction and refinement, a process in which it loses most of the phenols, although preserving the fatty acids.
The benefits from olive oil are derived from its unique nutritional composition, and especially three of its components:
- Monounsaturated fatty acids. The most abundant is the oleic acid that represents 55-83% of the olive oil. It also has polyunsaturated fatty acids (4-20%, linoleic and linolenic acids) and saturated fatty acids (8-14%, palmitic and stearic acids).
- Hydroxytyrosol. A minor component in extra virgin olive oil, it is a polyphenol with important anti-inflammatory and anti-tumour effects. It also improves the lipid profile and reducing oxidative stress.
- Oleuropein. It is an antioxidant found in unripe olives and olive tree leaves. It has shown improvements in various inflammation models and anti-tumour properties by inducing the apoptosis (programmed cellular death) in cancerous cells, especially in colon cancer.
Effects on cardiovascular diseases
Oxidative stress initiates the atherosclerotic process that damages the endothelium of blood vessels, increasing the risk of heart attacks and other cardiovascular disorders.
Risk factors for developing cardiovascular disorders are smoking, sedentarism and low-quality diets. Vegetable, fruits and good-quality fats have though a beneficial impact on these complications.
The extra virgin olive oil is useful as a tool for primary prevention in healthy individuals by reducing the level of some risk parameters (interleukin-6, VCAM and ICAM-1). Additionally, it helps to reduce the levels of “bad cholesterol”, or LDL, while increasing the levels of the “good cholesterol”, or HDL.
High levels of HDL in plasma are good because it works by transporting the cholesterol from the tissues to the liver, where it is prepared for excretion (bile and faeces).
But the extra virgin olive oil can also be used in secondary prevention in sick individuals. In a study the ingestion of 19g of olive oil over 1 year increased the HDL levels in patients with high cardiovascular risk. In another study with obese adult women a high-fat breakfast with 25mL of extra virgin olive oil reduced body fat and blood pressure. And these are only 2 examples of the positive cardiovascular effects associated with the regular ingestion of extra virgin olive oil.
These effects are synergistically potentiated when extra virgin olive oil was combined with fish oil. Therefore, individuals receiving 10mL/day of extra virgin olive oil and 3g/day of fish oil diminished the ratio between bad and good cholesterol (LDL/HDL). Olive oil helped cell membranes in the uptake of the omega-3 from fish oil. Simultaneous consumption was better than each of them on their own.
Effects on gut microbiota
The composition of gut microbiota is a protective factor against cardiovascular and inflammatory diseases, and its balance is key for health maintenance.
The consumption of extra virgin olive oil is linked to a higher biodiversity of intestinal bacteria. Each fatty acid has different effects, although the mechanisms involved are not understood yet. Polyphenols influence the microbiota composition acting as prebiotics, by inhibiting the growth of pathogenic bacteria, such as E. coli, and stimulating the probiotics, such the Bifidobacterium.
Effects on inflammation
Different studies have shown that diets rich in polyphenols and monounsaturated fatty acids are associated with reduced production of cytokines (TNF-alpha and IL-6) by fat tissue. These are the molecules involved in inflammatory processes.
Closely associated to the Mediterranean Diet is the extra virgin olive oil. Its intake generates health benefits in many studies carried out in animals and humans, among them:
- Prevention of cardiovascular diseases.
- Improvement of inflammatory parameters.
- Better gut microbiota composition.
The effects linked to the extra virgin olive oil are related to its composition:
- Content of monounsaturated fatty acids, especially oleic fatty acid.
- Polyphenols, especially oleuropein and hydroxytyrosol.
If you are not using it yet: don´t forget to introduce extra virgin olive oil into your diet.
Your health will thank you.
Effects of Olive Oil and Its Minor Components on Cardiovascular Diseases, Inflammation, and Gut Microbiota.
Marcelino G, Hiane PA, Freitas KC, Santana LF, Pott A, Donadon JR, Guimarães RCA.
Nutrients. 2019 Aug 7;11(8). pii: E1826. doi: 10.3390/nu11081826.