NUTR 2105 Ch 5 Notes
NUTR 2105 Ch 5 Notes 2105
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This 5 page Class Notes was uploaded by Veronica Fostik on Tuesday February 9, 2016. The Class Notes belongs to 2105 at East Carolina University taught by Kimberly Lukhard in Spring 2016. Since its upload, it has received 27 views. For similar materials see Nutrition Science in Nutrition and Food Sciences at East Carolina University.
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Date Created: 02/09/16
NUTR 2015 CH 5 Food Choices Poor health from too much/too little fat Poor health Lipids Triglyceride- glycerol & 3 fatty acids Fatty acids- even number of carbons & saturated/unsaturated Phospholipids Sterol Chemist’s View of Triglycerides & Fatty Acids more carbons & hydrogens per gram (energy) Fatty acids o Organic o Methyl group & acid group o Even number of carbons (18 carbon fatty acids in food) o Saturated- full of hydrogens o Unsaturated- lacking hydrogens o Double bonds near methyl end (omega number) o Linoleic acid o Monounsaturated fats (omega- 9 group) Triglycerides o Glycerol backbone o 3 fatty acids o Condensation reactions form them o Mixture of fatty acids Glycerol + 3 fatty acids triglyceride + 3 water molecules Degree of unsaturation o Firmness- length of carbon chain (polyunsaturated fats & unsaturated fats) o Stability- oxidation & spoilage of fats o Hydrogenation o Trans-fatty acids Chemist’s View of Phospholipids & Sterols Phospholipids o soluble in water & fat o emulsifiers/ part of cell membranes o lecithin Sterols o Cholesterol & plant sterols o Body compounds made from cholesterol Lipid Digestion Fats are hydrophobic Digestive enzymes are hydrophilic Fat digestion dismantles triglycerides (monoglycerides, fatty acids & glycerol) Mouth o Lingual lipase Stomach o Muscle contractions o Gastric lipase Small Intestine o Cholecystokinin (CCK)- gall bladder releases bilebile is emulsifier o Pancreatic lipase o Hydrolysis (triglycerides & phospholipids) Bile Roots o Blood cholesterol levels o Bile is stored in GALLBLADDER o Bile emulsifies fats in SMALL INTESTINE o Bile reabsorbed back into blood o Bile is made from cholesterol in LIVER o Bile trapped by soluble fibers excreted in feces in COLON Lipid Absorption Directly in bloodstream o Glycerol & short/medium chains of fatty-acids Lymphatic system o Micelles diffuse into intestinal cells o Triglycerides reassemble o Lots of proteins- chylomicrons o Bypass liver Lipid Transport Lipoproteins 1. Chylomicrons- largest & least dense a. Transport diet-derived lipids b. Liver removes remnants from blood 2. Very Low density lipoproteins (VLDL) a. Made in liver b. Proportion of lipid shift 3. Low density lipoproteins (LDL) a. Supports cell needs b. Liver regulation 4. High density lipoproteins (HDL) a. Remove cholesterol from from cells b. Carry cholesterol to liver to recycle c. Anti-inflammatory properties Role of Triglycerides PROVIDE CELLS WITH ENERGY (9 kcal/g) o Unlimited ability to store fat energy in body Adipose tissues- secrete hormones (adipokines) Skin insulation, shock absorption, cell membranes & cell signaling pathways Essential Fatty Acids Linoleic acid- omega 6 fatty acid Linoleic acid- omega 3 fatty acid (DHA, EPA- eicosanoids) Fatty acid deficiencies Lipid Metabolism Adipose cells store fat after meals o Lipoprotein lipase (hydrolyzes triglycerides) o Triglycerides reassembled in adipose tissues Uses fat for energy o Protein sparing o Energy deprivation (fasting & ketone bodies) Health Effects of Lipids Heart disease o High blood cholesterol (saturated fat & trans fats increase LDL cholesterol) o Monounsaturated fats- replace saturated & trans fats Reduces blood cholesterol o Omega 3-fatty acids Omega 6:3 ratio Cancer o Promotion instead of initiation o Dietary fat & risks for each type of cancer Obesity o Cutting fat from diet lowers kcalories Recommended Intake of Fat Eat low amounts saturated & trans fats Eat low amounts of cholesterol 20-35% of fat in diet per day DV is on labels for saturated fat & cholesterol Risk of insufficient fat intake Guidelines Vitamins A, D, E,K are fat-soluble Alternatives for meats Specific milk & milk products Vegetables, fruits & grains lower consumption of fat Invisible fat- fried & baked goods Don’t eat lots of processed foods Fat replacers Compare products Olive oil has benefits for heart health o Replaces saturated fats Nuts have LDL cholesterol o Fat composition Fish has Omega 3-fatty acids o Beware of contaminants Saturated fats in foods o Meats, whole milk products, tropical oils o Zero saturated fat doesn’t exist Trans fat- limit hydrogenated foods Mediterranean Diet is low in all fats & rich in fiber, carbs, & nutrients Misc Human body uses longer chain Omega 3’s & Omega 6’s to make substances: eicosanoids o Eicosanoids are hormone like compounds- only affect the cells where they are made or near & have different effect on each cell o Eicosanoids made from Omega 3 fatty acids Help decrease blood pressure, prevent clot formation, reduce inflammation & protect against irregular heartbeat o Eicosanoids from Omega 6 fatty acids Promote clot formation, inflammation, & blood vessel constriction Omega 6 acids protect heart by decreasing LDL levels & increasing insulin resistance Foods rich in Omega 3 fatty acids o Fish, fish oils, flaxseeds & chia seeds Foods rich in Omega 6 fatty acids o Vegetable oils, fat food products packaged goods, crackers, cookies, cakes & chips o Need 1:1 ratio but most Americans eat 20:1 ratio of Omega 6 to Omega 3 fatty acids Adipokines- hormones secreted by fat cells o Help regulate energy balance & help body functions o When weight changes, so do Adipokines o Adipokine resistin increases in obesity o When you lose weight, Adiponectin produced which prevents diabetes Fat o Exces fat stored in adipose cells for later use o LDL’S are bad BAD cholesterol o HDL’s HEALTHY cholesterol Lipoprotein lipase breaks apart triglycerides from lipoproteins in blood
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