NUTR 202 1nd Edition Lecture 9 Chapter 5 Lipids Fats Phospholipids and Sterols Lipid is the chemical term for fats Composed of carbon hydrogen oxygen they are organic compounds not soluble with water Three types or categories of lipids Triglycerides sterols and phospholipids The functions of fat include 1 Energy dense source of fuel main source may survive 2 wks without eating 9 kcal gram 2 Cholesterol sterol regulatory and structural role 3 Assists with absorption of fat soluble vitamins 4 Essential part of the cell membranes Cholesterol Phospholipids 5 Insulates body to maintain body temperature 6 Cushions bones organs nerves 7 In foods adds flavor texture aroma All fatty acids consist of a chain of carbon and hydrogen atoms with an acid group COOH at one end They are hydrophobic more than 20 diff kinds Types of fatty acid differ based on 1 Number of carbons length of the chain 2 Double or single bonds between carbons These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute C C or C C 3 Total number of DOUBLE BONDS 4 Location of the double bonds If you have no double bonds saturated fatty acid One double bond monounsaturated fatty acid all C s bonded to 2 H s More than one double bond polyunsaturated Saturated fatty acids found predominately in ANIMAL based foods Also found in palm oil coconut oil Association with heart disease Unsaturated fatty acids found predominately in Plant based foods Cooking oils Nuts seeds Trans fatty acids can be created by hydrogenation Causes some double bonds to become saturated with hydrogens If hydrogens on same side of carbon chain cis If hydrogens on opposite side of carbon chain trans Improves storage or shelf life of certain products that contain these fats Association to heart disease Essential Fatty Acids must be acquired in diet Types of polyunsaturated fatty acids Humans unable to create double bond in the omega 3 and omega 6 positions 2 essential fatty acids Linoleic acid omega 6 and omega 3 alpha linoleic acid omega 6 and 3 Triglycerides Are the major form of lipid in food and in the body Consist of three fatty acids attached to a glycerol backbone 3 C molecule Usually contain mixture of fatty acids Phospholipids The type of lipid that has a glycerol backbone two fatty acids and a phosphate group is called phospholipid Ex lecithin Phosphorus containing head Fatty acid tail hydrophilic hydrophobic Importance in body foods and in cell membrane lipid bilayer emulsifier Lectin major phospholipid in cell membranes and foods Sterols are comprised mainly of four connecting rings of carbon and hydrogen Example Cholesterol Important role in cell membrane structure Precursor of important compounds in body Ex hormones bile acid vitamin D Not required in diet since body makes all cholesterol needed Plant sterols also consumed in diet Only in foods derived from ANIMAL sources PLANTS do not contain cholesterol foods made only from plant sources have no cholesterol Plants contain PLANT STEROLS with same function plants as cholesterol in animals form plant cell membranes PLANT STEROLS in diet reduce cholesterol in human body Cholesterol is not a source of energy Its non essential Total fat Saturated fat 20 to 35 of kcalories from fat Less than 7 of total calories Cholesterol Less than 300 mg per day TRANS FAT should be zero Sources Animal sources meat cheese dairy Plant sources vegetable oils nuts avocados Hidden dietary fat French fries pizza pasta dishes baked goods salad dressings Foods that contain Unsaturated fats both mono poly are better for your health compare to Foods high in saturated fat Foods high in cholesterol Foods high in trans fats Nutrition Facts label Daily value for total fat and sat fat 5 considered low 20 considered high Nutrient content claims per serving Low fat 3gm fat Low cholesterol 20 mg cholesterol Lean 10g fat 4 5 g saturated fat 95 mg cholesterol Extra Lean 5g fat 2 g saturated fat 95 mg cholesterol