Fatty acids

Fatty acids are the simplest lipids and consist of long hydrocarbon chains.

Fatty acids are a component of more complex lipids and provide most of the calories from dietary fats.

Fatty acids are classified based on the number of carbon atoms in the molecule (chain length). They can be saturated, i.e. without double bonds. These include lauric (C12:0), myristic (C14:0), palmitic (C16:0) and stearic (C 18:0) acids. Monounsaturated fatty acids, such as oleic acid (C18:1), contain one double bond. Polyunsaturated fatty acids, such as linoleic acid (C 18:2), contain more than one double bond. Some of the polyunsaturated fatty acids, namely linoleic and linolenic acid, cannot be synthesized in the body, so they are classified as essential fatty acids. They must be supplied to the body with food. These acids are used to synthesize other long-chain polyunsaturated fatty acids, which are important in the synthesis of eicosanoids. Unsaturated fatty acids are also classified according to the position of the double bond, i.e. omega-9 (Q-9, or n-9), omega-6 (Q-6, or n-6), omega-3 (Q-3, or n-3), based on the position of the first double bond from the methyl end group. In addition, these unsaturated fatty acids are also classified based on the isomeric configuration of the double bonds, namely cis and trans, which determine the properties of these acids.

The type of fatty acid can affect the physical properties of the fat, its absorption, absorption, metabolism, utilization, and ultimately health.

In the American diet, approximately 80% of the total fat comes from meat, fish, salads, cooking and baking fats, and dairy products. In addition, meat, poultry, fish, eggs, and dairy products are major sources of saturated fatty acids. Cereal products such as yeast breads, cakes, and cookies contribute significantly to the intake of mono- and polyunsaturated fatty acids. Fish and shellfish are major sources of long-chain polyunsaturated fatty acids.

Triacylglycerides

Dietary fats and vegetable oils are triacylglycerides (TAGs), in which three fatty acids are esterified into glycerol with a predominance of a characteristic fatty acid, which affects the overall composition of the diet and the choice of food intake. Fats and oils consist of many fatty acids, presented in proportions characteristic of the corresponding fat or oil. Usually, one or two fatty acids predominate in a fat or oil. For example, linoleic acid makes up 78% of the fatty acids in sunflower oil. In volume, vegetable oils, except for tropical coconut and palm, are the main sources of unsaturated fatty acids, and animal fats are sources of saturated fatty acids, therefore, it is possible to change the fatty acid profile in the diet only by replacing the fat source. In addition, biotechnology allows the production of fats and products with a specific fatty acid composition, the so-called engineered foods.

Dietary guidelines and fat intake

General dietary recommendations call for total energy intake to be <30% from total fat and <10% from saturated fatty acids, and cholesterol intake to be <300 mg per day.

Several national surveys cited by various US organizations indicate that total population fat intake has declined to approximately 34% of calories since 1990. The data show that only 18, 14, and 21% of men and 18, 18, and 25% of women aged 6-11, 12-19, and over 20 years, respectively, received <30% of their energy from fat.

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