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Chapter 5: Lipids, Fats, Oils, Phospholipids, and Sterols

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lipid
family of organic compounds soluble in organic solvents, but not water; 3 main classes
cholesterol
sterol; made in body for variety of purposes
fats
lipids that are solid at room temperature
oils
lipids that are liquid at room temperature
cardiovascular disease
disease of the heart and blood vessels
triglycerides
class of lipids that is chief form of fat in foods and in the body; 3 units of fatty acids and 1 unit of glycerol
phospholipids
class of lipids that are similar to triglycerides but each has a phosphorus-containing acid in place of one of the fatty acids; present in all cell membranes
lecithin
phospholipid manufactured by the liver; major constituent of cell membrane
sterols
class of lipids that have structure similar to cholesterol
essential fatty acids
fatty acids that the body needs but can't make in amounts sufficient to meet physiological needs
satiety
feeling of fullness or satisfaction that people experience after meals
fatty acids
organic acids composed of carbon chains of various lengths; has an acid end and hydrogens attached to all of the carbon atoms on the chain
glycerol
organic compound, 3 carbons long, serves as backbone of triglycerides
saturated fatty acid
fatty acid carrying maximum possible number of hydrogen atoms
point of unsaturation
site in a molecule where bonding is such that additional hydrogen atoms can easily be attached
unsaturated fatty acid
fatty acid that lacks some hydrogen atoms and has one or more points of unsaturation
monounsaturated fatty acid
fatty acid containing one point of unsaturation
polyunsaturated fatty acid
fatty acid with 2 or more points of unsaturation
saturated fats
triglycerides in which most of fatty acids are saturated
trans fats
fats that contain any number of unusual fatty acids formed during processing
monounsaturated fats
triglycerides in which most of the fatty acids have one point of unsaturation
polyunsaturated fats
triglycerides in which most of the fatty acids have two or more points of unsaturation
emulsifier
substance that mixes with both fat and water and permanently disperses the fat in water, forming an emulsion
emulsification
process of mixing lipid with water by adding an emulsifier
bile
emulsifier made by the liver from cholesterol and stored in gallbladder; emulsifies fats so that enzymes in watery fluids may contact it and split fatty acids from their glycerol for absorption
monoglycerides
products of digestion of lipids; consist of glycerol molecules with one fatty acid attached
lipoproteins
transport vehicles for lipids in blood and lymph
chylomicrons
lipoproteins formed when lipids from a meal are combined with carrier proteins in cells of intestinal lining; transport food fats through the watery body fluids to liver and other tissues
very-low-density lipoproteins
lipoproteins that transport triglycerides and other lipids from liver to various tissues in body
low-density lipoproteins (LDL)
lipoproteins that transport lipids from liver to other tissues; contain large proportion of cholesterol
high-density lipoproteins (HDL)
lipoproteins that return cholesterol from tissues to liver for dismantling and disposal; contain large proportion of protein
inflammation
immune defense against injury, infection, or allergens marked by heat, fever, and pain
oxidation
interaction of a compound with oxygen
dietary antioxidant
substance in food that significantly decreases the damaging effects of reactive compounds, such as reactive forms of oxygen and nitrogen on tissue functioning
eicosanoids
biologically active compounds that regulate body functions
linoleic acid
(18:2); omega-6; DRI=5%-10% of kcals; vegetable oils
linolenic acid
(18:3); omega-3; DRI=0.6%-1.2% of kcals; fish, flax, canola, soy, walnuts, human milk
omega-6 fatty acid
polyunsaturated fatty acid with its endmost double bond 6 carbons from end of the carbon chain
arachidonic acid
omega-6 fatty acid derived from linoleic acid
omega-3 fatty acid
polyunsaturated fatty acid with its endmost double bond 3 carbons from the end of the carbon chain; linolenic acid
EPA, DHA
omega-3 fatty acids made from linolenic acid in the tissues of fish
methylmercury
any toxic compound of mercury to which a characteristic chemical structure, a methyl group, has ben added; causes nerve damage in people
hydrogenation
process of adding hydrogen to unsaturated fatty acids to make fat more solid and resistant to the chemical change of oxidation
smoking point
temperature at which fat gives off an acrid blue gas
trans-fatty acids
fatty acids with unusual shapes that can arise when hydrogens are added to the unsaturated fatty acids of polyunsaturated oils