Fats, The Importance of Fats in Health and Nutrition PDF

Fats, The Importance of Fats in Health and Nutrition Over 90% of fats are in the form of triglycerides, which consist of a glycerol backbone with fatty acids esterified on each of the three hydroxyl groups of the glycerol molecule. Fatty acids Fatty acids have a backbone made of carbon atoms....

Fats, The Importance of Fats in Health and Nutrition Over 90% of fats are in the form of triglycerides, which consist of a glycerol backbone with fatty acids esterified on each of the three hydroxyl groups of the glycerol molecule. Fatty acids Fatty acids have a backbone made of carbon atoms. They vary in the number of carbon atoms, and in the number of double bonds between them. For example, butyric acid (C4:0), palmitic acid (C16:0) and arachidic acid (C20:0), contain 4, 16 or 20 carbon atoms in their chain, respectively. Triglycerides Fatty acids Based on the number of carbon atoms in the alkyl chain length, fatty acids can be classified into : Short-chain fatty acids (SCFA) are fatty acids with up to 5 carbon atoms, medium-chain fatty acids (MCFA) have 6 to 12, long-chain fatty acids (LCFA) 13 to 21, and very long chain fatty acids (VLCFA) are fatty acids with more than 22 carbon atoms. The majority of naturally occurring fatty acids, both in the diet and in the body, contain Clasification of Lipids Simple Lipids Esters of fatty acids with various alcohols. 1.Fats: Esters of fatty acids with glycerol. Oils are fats in the liquid state 2.Waxes: Esters of fatty acids with higher molecular weight monohydric alcohols Complex Lipids (Compound Lipids) Esters of fatty acids containing groups in addition to alcohol and fatty acid. 1.Phospholipids: These are lipids containing, in addition to fatty acids and alcohol, phosphate group. They frequently have nitrogen-containing bases and other substituents, eg, in glycerophospholipids the alcohol is glycerol and in sphingophospholipids the alcohol is sphingosine. 2.Glycolipids (glycosphingolipids): Lipids containing a fatty acid, sphingosine and carbohydrate. 3.Other complex lipids: Lipids such as sulfolipids and amino lipids. Lipoproteins may also be placed in this category. Derived Lipids Derived lipids are produced by the hydrolysis of simple and complex lipids. These include fatty acids, glycerol, steroids, other alcohols, fatty aldehydes, and ketone bodies, hydrocarbons, lipid-soluble vitamins, and hormones. Structure of a triglyceride and saturated, monounsaturated and polyunsaturated fatty acids.  Cis and Trans Form Unsaturated fatty acids can also be classified as "cis" (bent form) or "trans" (straight form), depending on whether hydrogen is bound on the same, or on the opposite side of the molecule. Most naturally occurring unsaturated fatty acids are found in cis form.  Classification of PUFA (omega fatty acids) PUFA can be further categorised into three main families according to the position of the first double bond starting from the methyl-end (the opposite side of the glycerol molecule) of the fatty acid chain: Omega-3, Omega-6 and Omega-9 Omega-3 (or n-3) fatty acids have the first double bond at the third carbon atom and include mainly alpha linolenic acid (ALA) and its derivatives eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).  Classification of PUFA (omega fatty acids) Omega-6 (or n-6) fatty acids have the first double bond at the sixth carbon atom and include mainly 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 and include mainly oleic acid.