Popular Science Book "Eat Less Oil, Eat Better Oil" (Wang Xingguo) Article Selection 25

6 Types of fatty acids

Fatty acids are the basic building blocks of triglycerides, the main component of oils and fats. There are many types, with forty or fifty common ones. They can be classified as follows based on differences in carbon chain length, degree of saturation and essentiality to the human body.

(1) Carbon chain length

According to the length of the carbon chain, they can be divided into long-chain fatty acids (more than 14 carbons), medium-chain fatty acids (6-12 carbons), and short-chain fatty acids (less than 6 carbons), but this division is not fixed. The fatty acids in edible oils are mainly fatty acids with a chain length of 18 carbons, such as oleic acid, stearic acid, linoleic acid, α-linolenic acid, etc., and palmitic acid with a carbon number of 16. Lauric acid with a carbon number of 12 and erucic acid with a carbon number of 22 are also common.

(2) Saturation

The degree of saturation indicates the number of double bonds in the carbon chain of fatty acids. Based on this, they can be divided into saturated fatty acids (no double bonds), monounsaturated fatty acids (one double bond), and polyunsaturated fatty acids (two or more double bonds). These three types of fatty acids have different effects on human health.

(3) Necessity for the human body

According to the necessity of fatty acids to the human body, they can be divided into essential fatty acids and non-essential fatty acids. Fatty acids in the human body can come directly from food or be synthesized by the body itself. However, the human body cannot synthesize all fatty acids. Essential fatty acids refer to fatty acids that are indispensable for the body to maintain normal metabolism but cannot be synthesized by the body itself, or the synthesis speed is too slow to meet the needs of the body and must be supplied through food. Only α-linolenic acid of the ω-3 family and linoleic acid of the ω-6 family can be called essential fatty acids.