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PRESENTATIONS 9, 14, 16, 21, 23 MARCH Carbohydrate/lipid/protein/alcohol 4/9/4/7 kcal/gram 17/37/17/29 kJ/gram Note alcohol = ethanol 2 Last time we talked about dietary carbohydrate in sports 3 Lecture 7 26 Jan. 2015 LIPIDS 4 OUTLINE OF LECTURE 7 1) LIPIDS DEFINED 2) STRUCTURES OF LIPIDS 3) LIPIDS IN FOODS 4) FUNCTIONS OF FATS IN FOODS 5) LIPID IDATME 6) FUNCTIONS OF LIPIDS ESSENTIAL OR NOT? HEALTHY AND UNHEALTHY METABOLISM 5 1) LIPIDS defined FAMILY OF COMPOUNDS THAT INCLUDES TRIGLYCERIDES (TG), PHOSPHOLIPIDS (PL) AND STEROLS OTHER DEFINITION WATER INSOLUBLE ORGANIC COMPOUNDS MADE UP OF C, H, AND O LIKE CARBOHYDRATES BUT LESS O AND THEREFORE 9 VS 4 KCAL/GM 6 2)STRUCTURES OF LIPIDS a) Triglycerides-fatty acids-structure, classification, in foods and function Structure Classification Organic acid Saturated 14:0 Monounsaturated 18:1 Polyunsaturated 18:2 n-6 18:3 n-6 (gamma-linolenic) 18:3 n-3 (alpha-linolenic) Glycerol Triglycerides Mixed triglycerides 7 REPLACE WITH FIG 5-2 ACETIC ACID 8 Fig. 5-1, p. 140 p. 134 p. 134 p. 135 p. 135 p. 135 p. 135 15 16 17 Fig. 5-4, p. 137 TRIGLYCERIDES CONTINUED TRIGLYCERIDES IN FOOD Processed fat-fat manipulated mechanically or chemically Hydrogenation- -trans-fatty acids 19 Fig. 5-7, p. 138 Fig. 5-8, p. 139 FUNCTION OF FATTY ACIDS IN FOOD ESSENTIAL- LINOLEIC AND LINOLENIC 22 B) Phospholipids- structure, classification, in foods and function Structure- 2 FATTY ACIDS (FA) and polar head group-generally but exceptions Classification Choline-containing phospholipids Ethanolamine-containing phospholipids Phosphatidylserine Phospatidylinositol Sphingomyelin 23 Fig. 5-9, p. 140 PHOSPHOLIPIDS CONTINUED Foods- found naturally Function Membranes Lipoproteins Cell signalling 25 C) Sterols- structure, classification, in foods and function Structure-Ring structure Classification-Sterols 26 Fig. 5-11, p. 141 STEROLS CONTINUED Foods- found naturally-cholesterol vs phytosterol Function Membranes Lipoproteins Bile acids Hormones Vitamin D 28 29 30 3)Lipids in foods All lipid classifications we have discussed are in foods Animals and plants have free fatty acids, triglycerides, and phospholipids 31 LIPIDS IN FOODS CONTINUED Animal have cholesterols (free and cholesterol esters) Plants have phytosterols (free and esterified) 32 LIPIDS IN FOODS CONTINUED GRAINS BREADS/OATMEAL < 1 G FAT/SERVING CROISSANT 10 G FAT/MEDIUM VERY LITTLE FAT 33 LIPIDS in FOODS CONTINUED FRUITS AND VEGETABLES BOILED POTATO –TRACE HOMEMADE HASHBROWNS 11 G FAT/1/2 CUP APPLE 0.4 G FAT/MEDIUM AVOCADO 15 G FAT/MEDIUM VERY LITTLE FAT OR NO FAT USUALLY 34 LIPIDS IN THE FOODS CONTINUED MILK, YOGURT AND CHEESE WHOLE MILK REGULAR YOGURT REGULAR CHEESE 8 G/CUP 4 G/CUP 9 G/28G (1 OZ) GENERALLY MORE FAT THAN GRAINS, FRUITS AND VEGETABLES BUT CAN ALSO GET FAT FREE, REDUCED FAT AND WHOLE FAT VARIETIES 35 LIPIDS IN FOODS CONTINUED MEATS, POULTRY, FISH, PEAS, BEANS, LENTILS GENERALLY MORE FAT THAN MILK, YOGURT AND CHEESE BUT CAN ALSO GET LEAN MEATS CHUCK BLADE AND PORK CHICKEN WITH SKIN FISH – SALMON - COD NUTS 11 G/ 3 OZ (84 G) 12 G/3 OZ (84 G) 5 G/3 OZ 0.7 G/3 OZ 14-21 G/3 OZ 36 LIPIDS IN FOODS CONTINUED MODIFIED FOODS CARBOHYDRATE REPLACERS (PECTIN) PROTEIN REPLACERS (EG DERIVED FROM A CORN PROTEIN) FAT REPLACERS (EG OLESTRA) 37 LIPIDS IN FUNCTIONAL FOODS MARGARINES- BENECOL -BECEL-PRO-ACTIV -CORN OIL -FLAX OIL -CANOLA OIL CHICKEN FEED- OMEGA 3 AND OMEGA 6 FATTY ACIDS 38 LIPIDS IN FUNCTIONAL FOODS CONTINUED FISH CANOLA/FLAX SEA BUCKTHORN OIL- MIX OF OMEGA 3 AND OMEGA 6 FATTY ACIDS 39 Fig. 5-6, p. 138 4)FUNCTIONS OF FATS IN FOODS •ABSORBING FLAVOURS AND AROMAS OF INGREDIENTS •PROVIDING FLAVOUR OF ITS OWN •CREAMY AND SMOOTH MOUTH TASTE •TENDERIZING AND ADDING MOISTURE 41 5) LIPIDS IDATME 42 INGESTION OF LIPIDS MOUTH-CHEWING TUBE INTRAVENOUS 43 DIGESTION OF LIPIDS goal of fat digestion fats start out separated from enzymes in gi (gastrointestinal tract) -why? mouth digestion of fat-sublingual lipase-minor in adults -triglycerides 44 DIGESTION OF LIPIDS Small intestine -bile -pancreatic and intestinal lipases – triglycerides -phospholipases -sterols not digested Large intestine - no digestion of lipids 45 ABSORPTION OF LIPIDS small molecules short chain fatty acids medium chain fatty acids glycerol direct to blood larger molecules monoglycerides long chain fatty acids micelles formed in intestine micelles into intestinal wall cells chylomicrons formed and released into lymph file:///D:/Media/Animations/chapter5/Absorption_of_Fat/0517.html 46 TRANSPORT OF LIPIDS lipoproteins- chylomicrons (CM) (POST-PRANDIAL ONLY) - very low density lipoprotein (VLDL) - low density lipoprotein (LDL) - high density lipoprotein (HDL) - ALBUMIN density change due to 2 factors 47 LIPOPROTEIN METABOLISM Chylomicrons- made in small intestine – acted on by lipoprotein lipase in blood to give remnant particle which is taken up liver VLDL (very low density lipoprotein) made VIA LIVER VLDL acted on by lipoprotein lipase in blood to give remnant particle (intermediate density lipoprotein or IDL) which is taken up by liver- liver puts out low density lipoprotein (LDL) HDL ( high density lipoprotein) and albumin made by liver 48 Fig. 5-4, p. 137 Fig. 5-4, p. 137 FATTY ACIDS METABOLISED VIA KREB’S CYCLE TO GIVE LOTS OF ATP Fig. 5-4, p. 137 LIPID EXCRETION -faeces-e.g. bile and undigested/unabsorbed lipid 52 6) FUNCTIONS OF LIPIDS- ESSENTIAL OR NOT?- HEALTHY AND UNHEALTHY METABOLISM 53 LIPIDS ESSENTIAL OR NOT ? YES-WHY ? HEALTHY ROLES 54 LIPIDS- ESSENTIAL OR NOT? YES - HEALTHY ROLES 1)INSULATION- HEALTHY ROLES Protective layer in body to help keep heat losses down 55 LIPIDS- ESSENTIAL OR NOT? YES HEALTHY ROLES 2)SUPPORT AND PROTECTION FOR INTERNAL ORGANS AND BONES Fat acts as support and cushioning for organs and cushioning for bones 56 LIPIDS- ESSENTIAL OR NOT? YES - HEALTHY ROLES 3)ABSORPTION OF FAT SOLUBLE VITAMINS Fat soluble vitamins cannot be absorbed without fat in the diet Why? 57 LIPIDS- ESSENTIAL OR NOT? YES - HEALTHY ROLES 4)CELL MEMBRANES Cholesterol and phospholipids are important in maintaining the structure and hence function of cell membranes What is a cell membrane? 58 LIPIDS- ESSENTIAL OR NOT? YES - HEALTHY ROLES 5) GIVES STRUCTURE TO MOLECULES Fatty acids give rise to triglycerides and phospholipids and cholesterol fatty acid complexes Structure of lipids in part dictates their function 59 LIPIDS- ESSENTIAL OR NOT? YES - HEALTHY ROLES 6)METABOLICALLY FAT STORED AS FAT- VERY EFFICIENT MAKING FAT FROM CARBOHYDRATE AND PROTEIN IS NOT VERY EFFICIENT ENERGY SOURCE-CAN STORE HUGE QUANITIES OF FAT 60 LIPIDS- ESSENTIAL OR NOT? YES - HEALTHY ROLES 7) IMPACT ON NUTRIENT ABSORPTION -GUT MOTILITY IS SLOWED -SLOWER RATE OF DIGESTION 61 62 63 64 FATS UNHEALTHY ROLES FAD DIETS NO FAT OR LESS THAN 10 % OF CALORIES AS LIPID IN DIET WITH ALL OR MOSTLY ALL OF ENERGY DIFFERENCE MADE UP WITH CARBOHYDRATE AVOID !!! 65 UNHEALTHY ROLES FAT TO FAT- OBESITY -OBESITY- TOUGH ON JOINTS, -MAY CONTRIBUTE TO ARTHRITIS -ELEVATES BLOOD PRESSURE- WHICH MAY GIVE ATHEROSCLEROSIS AND HEART ATTACKS AND STROKE 66 UNHEALTHY ROLES OBESITY CONTINUED -ELEVATES FREE FATTY ACIDS IN THE BLOOD WHICH MAY GIVE INSULIN RESISTANCE -IF EXCESS FAT IN THE DIET THIS MAY CROWD OUT OTHER NUTRIENT CLASSES 67 SUMMARY OF LECTURE 7 1) LIPIDS DEFINED 2) STRUCTURES OF LIPIDS 3) LIPIDS IN FOODS 4) FUNCTIONS OF FATS IN FOODS 5) LIPID IDATME 6) FUNCTIONS OF LIPIDS ESSENTIAL OR NOT? HEALTHY AND UNHEALTHY METABOLISM 68 NEXT TIME DIETARY LIPIDS IN SPORTS 69