281 Virgin Olive Oil Benefits MONOUNSATURATED LIPID/S or MONOUNSATURATED FAT/S MONOUNSATURATED -lipids-; MONOUNSATURATED -fatsOmega-9; ω-9; n-9 (similar terms referring to the same concept) (To understand the general nomenclature and structural principles of fatty acids, see “Fatty acids” in “CONCEPTS”, the first section of this topic (“LIPIDS”). As for monounsaturated fatty acids, they are described in the Introduction to this section -UNSATURATED LIPID/S-) These are fats rich in monounsaturated fatty acids. From a chemical perspective, these fatty acids contain a single double bond between carbon atoms, often located at the ninth carbon in the hydrocarbon chain (ω-9). The chain length may vary between 10 and 32 carbon atoms, although the most common form contains 18 carbons. At room temperature, monounsaturated fats are liquid but begin to solidify when cooled. These fatty acids can be obtained from food or synthesised by the body from stearic acid (C18:0 -saturated-), through the action of an enzyme that introduces a double bond at the 9-10 position of the hydrocarbon chain. This process mainly produces oleic acid, although palmitoleic acid is also formed. Monounsaturated fatty acids are not considered essential, as the body can produce them. However, dietary intake is an important source of oleic acid, their most representative form. Oleic acid plays a key role in maintaining cell membrane structure, among other biological functions, and is the most abundant fatty acid in the cells of most mammals, accounting for around 40% of total fatty acids. Monounsaturated fatty acids in food are mainly found in plant-based sources, although they are also present in smaller amounts in some animal products, such as meat and dairy. Most vegetable oils contain them, especially olive oil, in which the predominant fatty acid is oleic acid (C18:1 –monounsaturated ω-9–), accounting for 55–83% of total fatty acids. Olive oil also contains linoleic acid (C18:2 –polyunsaturated ω-6–): 3.5–21%, palmitic acid (C16:0 –saturated–): 7.5–20%, alpha-linolenic acid (C18:3 –polyunsaturated ω-3–): up to 1.5%, along with traces of other fatty acids. The precise fatty acid composition of olive oils varies depending on their origin and method of production. Oleic acid is also a major component of rapeseed oil (canola), making up 56–70% of total fatty acids. It is also found in olives, avocados, and nuts. Oleic acid, together with omega-3 polyunsaturated fat (ω-3), is considered a healthy fat and is therefore recommended as a regular part of the diet. Although some data remain controversial, there is evidence supporting its beneficial effects on lipid profile (reduction of LDL cholesterol –the “bad” cholesterol– and triglycerides, and an increase in HDL cholesterol –the “good” cholesterol–) and on other cardiovascular risk factors. Its intake has also been linked to lower fat mass and lower systolic (maximum) and diastolic (minimum) blood pressure. Results from studies assessing the role of monounsaturated fatty acids on insulin sensitivity and diabetes risk are inconsistent. However, a beneficial effect has been described when they replace saturated fats or carbohydrates. Regarding cancer, while experimental studies clearly suggest a protective effect, human and epidemiological data remain limited and contradictory. Finally, numerous scientific studies indicate that prolonged intake of virgin olive oil -rich in these fats- leads to the formation of less oxidisable mitochondrial membranes, supporting healthier ageing. This has been observed in animal models and, to a lesser extent, in humans.
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