OLIVE OILS AND HEALTH 40 Phospholipids are composed of glycerin, fatty acids, a nitrogenated compound (choline), and phosphor as phosphate. The most important phospholipids are the lecithins (or phosphatidylcholines). They are relevant in the structure and function of cellular membranes, as emulsifiers, and help transport fats in and out of cells. In addition, they have been linked to beneficial cardiovascular effects. Sterols include cholesterol (Figure 1.4a), characteristic of animal fats, and phytosterols from vegetable fat which, with a similar structure to that of cholesterol, have the healthy property of being able to reduce cholesterol absorption. Fats also contain, mainly vegetable, carotenoids (yellow, orange, or red pigments, which are antioxidants), and chlorophylls, found only in vegetable fats (green pigments which give oils their characteristic colour), and terpenoids. Concerning fats, we must consider the “visible” ones (oils or lard for flavouring/ cooking, and the fat you can see in meat) and the “non-visible” or “non-isolated” ones (from fish or dairy products, particularly cheese) which also include the interstitial fat found in meat. A certain amount of dietary fat is needed. A proper diet for a healthy adult should provide around 60 - 90 grams of fat per day, corresponding to 20-30% of energy, or up to 35% if the main dietary fat is olive oil. It is advisable that fat ingestion be around a third for each type (monounsaturated, polyunsaturated, and saturated) with the latter not exceeding a third of the total fat content. The predominant fat should be monounsaturated and there must be a minimum of polyunsaturated (no more than 20-30%) that should not exceed. Figura 1.3: Ácidos grasos esenciales Linolenic acid C18H30O2 HO O B) OH O Linoleic acid C18H32O2 A) HIDROGEN OXYGEN CARBON DOUBLE-BOND Figura 1.4: Colesterol LDL LDL (Bad Cholesterol) Accumulater in our arterial blood vesseles. HDL HDL(Good Cholesterol) Helps to eliminate the bad cholesterol LDL HDL B) A) Figure 1.4: Cholesterol. HO
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