Fats
Fats are part of a large group of compounds known as lipids, which also include waxes, sterols (e.g. cholesterol), fat-soluble vitamins, monoglycerides, diglycerides, triglycerides, and phospholipids. Dietary fats are predominantly triglycerides, comprising three fatty acids attached to a glycerol backbone. Each fatty acid is a chain of carbon atoms, whose number and method of attachment varies. Short-chain fatty acids (SCFA) have up to 5, medium-chain fatty acids (MCFA) have 6 to 12, long-chain fatty acids (LCFA) have 13 to 21, while very long-chain fatty acids (VLCFA) have more than 22 carbon atoms. The majority of naturally occurring fatty acids, both in the body and in the diet, are between 16 and 18 carbon atoms in length. The carbon atoms within these fatty acids may be attached via a single or double chemical bond, which determines their classification. Saturated fatty acids (SFA) contain only single bonds, monounsaturated fatty acids (MUFC) contain one double bond, and polyunsaturated fatty acids (PUFA) contain more than one double bond between carbon atoms. PUFA are further classified according to the position of the first double bond from the methyl (or omega) end of their carbon atom chains;
- Omega-3 (or n-3) fatty acids have the first double bond at the third carbon atom, examples of which include alpha linolenic acid (ALA) and its’ derivatives eicosapentanoic acid (EPA) and docosahexanoic (DHA)
- Omega-6 (or n-6) fatty acids have the first double bond at the sixth carbon atom, examples of which include linoleic acid (LA) and its’ derivative arachidonic acid (AA)
- Omega-9 (or n-9) fatty acids have the first double bond at the ninth carbon atom, such as oleic acid (OA)
Both chain length and degree of saturation influence the functional properties of fatty acids and their role in human nutrition. Increasing evidence suggests that a diet low in saturated fatty acids and high in unsaturated fatty acids of long-chain length has a positive impact on human health, particularly so in the prevention of cardiovascular disease.
How much do I need?
What is their function?
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