Jaymie Ticknor Intro Nutrition Science 2460 Sect 002 12 June 2014 Fats Chapter 5 What Are Fats Lipids a diverse group of organic substances that are insoluble in water Include triglycerides phospholipids and sterols Fats and oils are two different types of lipids Fats are solid at room temperature Oils are liquid at room temperature Triglycerides Are the Most Common Food Based Fat Triglyceride a molecule consisting of three fatty acids attached to a three carbon glycerol backbone Also called triacylglycerols Most common form of fat in our diet The form in which most of our body fat is stored referred to as adipose tissue metabolically active tissue Fatty Acids long chains of carbon atoms bound to each other as well as to hydrogen atoms Contain an acid group carboxyl group at one end of their chain Glycerol an alcohol composed of three carbon atoms It is the backbone of a triglyceride molecule Saturated Fats Contain the Maximum Amount of Hydrogen Saturated Fatty Acid SFA a fatty acid that has no carbons joined together with a double bond 40 60 energy Generally solid at room temperature Coconut oil palm kernel oil butter cream whole milk and beef animal based Unsaturated Fats Contain Less Hydrogen Monounsaturated Fatty Acid MUFA a fatty acid that has two carbons in the chain bound to each other with one double bond Generally liquid at room temperature Olive oil canola oil and cashew nuts plant foods 80 90 energy Polyunsaturated Fatty Acid PUFA a fatty acid that has more than one double bond in the chain Generally liquid at room temperature Cottonseed canola corn and safflower oils Trans Fatty Acids Have Hydrogen Atoms on Opposite Sides Cis fatty acid has both hydrogen atoms located on the same side of the double bond whole foods Trans fatty acid hydrogen bonds are attached on diagonally opposite sides of the double carbon bond cow s milk and meat but also in processed foods Hydrogenation the process of adding hydrogen to unsaturated fatty acids making them more saturated and thereby more solid at room temperature If only some of the double bonds are broken the fat produced is called partially hydrogenated Some Triglycerides Contain Essential Fatty Acids Essential Fatty Acids EFAs fatty acids that must be consumed in the diet because they cannot be made by our body Linoleic Acid an essential fatty acid found in vegetable and nut oils One of the Omega 6 fatty acids Have a double bond six carbons from the omega end AI is 14 17 g per day for adult men and 11 12 g per day for women 19 Alpha Linolenic Acid ALA an essential fatty acid found in leafy green vegetables flaxseed oil soy oil and other plant foods An Omega 3 fatty acid AI is 1 6 g per day for adult men and 1 1 g per day for adult women Eicosapentaenoic Acid EPA and Docosahexaenoic Acid DHA omega 3 fatty acids available from marine foods and as a metabolic derivative of alpha linolenic acid They are found in fish shellfish and fish oils Fish that naturally contain more oil salmon and tuna are higher in EPA and DHA than lean fish cod or flounder EPAs are precursors to important biological compounds called eicosanoids Phospholipids Combine Lipids with Phosphate Phospholipids a type of lipid in which a fatty acid is combined with another compound that contains phosphate Unlike other lipids phospholipids are soluble in water The liver uses phospholipids called lecithins to make bile Sterols Have a Ring Structure Sterols a type of lipid found in foods and the body that has a ring structure Cholesterol is the most common sterol in our diets Found in animal products such as butter egg yolks whole milk meats and poultry Why Do We Need Fats Fats Enable the Transport of Fat Soluble Vitamins Dietary fat enables the transport of the fat soluble vitamins A D E and K our body needs for many essential metabolic functions How Does Our Body Process Fats Absorption of Fat Occurs Primarily in the Small Intestine Micelle a spherical compound made up of bile and phospholipids that can trap the free fatty acids and monoglycerides as well as cholesterol and phospholipids and transport these products to the enterocytes for absorption Lipoprotein a spherical compound in which fat clusters in the center and phospholipids and proteins form the outside of the sphere Chylomicron a lipoprotein produced in the enterocyte Transports dietary fat out of the intestinal tract Chylomicron remnants as the cells take up the fatty acids the chylomicrons shrink in size and become more dense Lipoprotein Lipase LPL an enzyme that sits on the outside of cells and breaks apart triglycerides so that their fatty acids can be removed and taken up by the cell How Much Fat Should We Eat Dietary Reference Intake for Total Fat The Acceptable Macronutrient Distribution Range for fat is 20 35 of total energy