Transcript FATS
FATS Chap 3 J Pistack MS/ED FATS Lipids – the true name for fats of all kinds Lipids include true fats, oils, and the related lipoids and sterols Dietary fats are found in both plant and animal products Lipids are insoluble in water and are greasy to the touch FATS Animal fats consist of a larger content of saturated fat, tend to have a higher melting point, and are solid at room temperature Plant derived fats have more unsaturated fat than animal fats, are normally in the form of oils, and have a lower melting point FATS Comprise elements carbon, hydrogen, and oxygen The basic structural unit of a true fat is one molecule of glycerol attached to one, two, or three fatty acids A fatty acid is composed of a chain of carbon atoms with hydrogen and a few oxygen atoms attached COMPOSITION OF FATS Monoglycerides - one fatty acid attached to glycerol Diglycerides – two fatty acids attached to glycerol Triglycerides – three fatty acids attached to glycerol COMPOSITION OF FATS Fatty acid carbon chains vary in length from 2 to 24 carbon atoms The length of the chain determines how the body transports and processes the fatty acid Short <6 Medium 8-12 Long 13-24 The length of the chain has dietary implications DEGREE OF SATURATION Saturated, trans-fat, unsaturated, monounsaturated, and polyunsaturated are names indicating the degree of hydrogen atom saturation of the carbon chain of a fatty acid A saturated fatty acid is filled with as many hydrogen atoms as the carbon atoms can bond with – thus, it is saturated DEGREE OF SATURATION In an unsaturated fatty acid the carbon atoms are joined together by one or more double bonds, not holding its maximum number of hydrogen atoms and is therefore unsaturated Double bonds between two carbon atoms when there are two few hydrogen atoms to fill all the spaces DEGREE OF SATURATION DEGREE OF SATURATION A monounsaturated fatty acid has only one carbon to carbon double bond A polyunsaturated fatty acid has more than one carbon to carbon double bond SATURATED FATS Solid at room temperature Animal or tropical oil origin Become rancid slowly – because of their chemical stability Products made with this fat have a longer shelf life All of the carbons are attached to hydrogen with no double bonds UNSATURATED FATS Liquid at room temperature Plant origins Become rancid quickly Have a double carbon bond (one or more hydrogen atoms could be added to the fatty acid chain) A double bond on a fatty acid causes the chain to bend or change shape Has a health benefit HYDROGENATION The addition of hydrogen to fat of vegetable origin If enough hydrogen is added to only break some of the double bonds the fat is considered partially hydrogenated If all double bonds are broken with added hydrogen the fat is completely hydrogenated TRANS FATTY ACIDS Made from unsaturated fats by commercially adding hydrogen at double-bond sites Causes an unnatural bend in the fatty acid chain Has a health detriment FUNCTIONS OF FATS Fats serve as a fuel source as well as a vehicle for fat-soluble vitamins –A, D,E, and K Due to the chemical composition of fats they are a more concentrated energy source than carbohydrates Gram for gram, fats furnish twice as many calories as carbohydrates FUNCTIONS OF FATS Seven major functions of fats in the body 1 - Supply fuel to most tissues 2 - Serves as an energy reserve 3 - Insulate the body 4 – Support and protect vital organs Act as a pad to absorb mechanical shock Protected organs include eyes and kidneys FUNCTIONS OF FATS 5 - Lubricate body tissues Oils manufactured by the body supply glands like the sebaceous glands, to secrete the oils to the skin to control water loss 6 - Form an integral part of cell membranes Plays a role in drug, nutrient, and metabolite transport Provides barrier against water soluble substances 7 -Carrier for fat-soluble vitamins CHOLESTEROL Not a true fat but belongs to a group called sterols Cholesterol is a component of many foods we eat Our bodies make about 1000 mg a day Present only in animal foods FUNCTIONS OF CHOLESTEROL A component of bile salts that aid digestion Essential component of cell membranes Found in the brain, nerve tissue, and blood Precursor for steroid hormone production Necessary for the production of Cortisone Adrenaline Estrogen Testosterone DIETARY FAT INTAKE Dietary fat plays a key role in health Some fat in the diet is necessary for optimal health Adds satiety and palatability (flavor) Good fats are found in nuts, avocado, canola, olive, and peanut oil Polyunsaturated fats are the form of omega 3 and omega 6