chapter 6: lipids
DESCRIPTION
Chapter 6: Lipids. Properties of Lipids. Do not readily dissolve in water Fats are solid at room temperature Oils are liquid at room temperature. Functions of Lipids. Provide energy Satiety Flavor and mouth feel Insulation Protect internal organs Transport fat-soluble vitamins - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/1.jpg)
Chapter 6: Lipids
![Page 2: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/2.jpg)
Properties of Lipids
• Do not readily dissolve in water
• Fats are solid at room temperature
• Oils are liquid at room temperature
![Page 3: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/3.jpg)
Functions of Lipids
• Provide energy• Satiety• Flavor and mouth feel• Insulation• Protect internal organs• Transport fat-soluble vitamins• Efficient storage of energy
– 80% lipid, 20% protein and water
![Page 4: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/4.jpg)
Triglycerides
• Triglycerides are the main form of lipids in food and body (storage)
• Energy dense (9 kcal /g)
![Page 5: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/5.jpg)
Triglycerides
Glycerol + 3 FA’s Triglyceride + 3 H20
H
H--C--OH
H--C--OH
H--C--OH
H
O
HO-C-R
O
HO-C-R
O
HO-C-R
+
H O
H--C--O--C--
O
H--C--O--C--
O
H--C--O--C--
H
R + H2O
R + H20
R + H20
![Page 6: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/6.jpg)
Text art 06_02
![Page 7: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/7.jpg)
7
Structure
• Esterification– Joining 3 fatty acids to a glycerol unit
• De-esterification– Release of fatty acids-results in free fatty acids
• Diglyceride– Loss of one fatty acid
• Monoglyceride– Loss of two fatty acids
![Page 8: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/8.jpg)
Structure of Fatty Acids
• Fatty acids– Function is dependent on:
• Length• Degree of saturation• Location of double bonds• Configuration/Shape
– Glycerol backbone
![Page 9: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/9.jpg)
Fatty Acid Chain Length
• Long chain FA: > 12 Carbons– Predominant in food (meats, fish)
• Medium chain FA: 6 - 10 Carbons– Account for ~4-10% of all FA
• Short chain FA: < 6 Carbons – Found in dairy products
![Page 10: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/10.jpg)
Saturated Fatty Acid
![Page 11: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/11.jpg)
Monounsaturated Fatty Acid
![Page 12: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/12.jpg)
Polyunsaturated Fatty Acid
![Page 13: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/13.jpg)
Location of Double Bonds
• Omega System– Double bond closest to omega (methyl) end– Omega: refers to the last carbon (methyl
group)– Omega 6 vs Omega 3 fatty acids
• Delta (alpha) System– Uses the carboxyl end and indicates location
for all double bonds
![Page 14: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/14.jpg)
Fatty Acid Structure
omega end alpha end
H H H H H H H H H H H H H H H H H O
H-C--C--C--C--C--C--C--C--C--C--C--C--C--C--C--C--C-C-OH
H H H H H H H H H H H H H H H H H
![Page 15: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/15.jpg)
Fatty Acid Nomenclature
![Page 16: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/16.jpg)
Configuration/Shape
• cis versus trans
![Page 17: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/17.jpg)
Common Fatty AcidsNAME STRUCTURE PROPERTIES Acetic acid 2:0 Formed from glucose and amino acid degradation Propionic acid 3:0 Formed from odd-chain fatty acids and branched-
chain amino acids Butyric acid 4:0 Found in cows’ milk and butter Decanoic acid 10:0 Major fatty acid in milk triglycerides Palmitic acid 16:0 End product of fatty acid synthesis in most tissues Stearic acid 18:0 Major fatty acid in gangliosides Oleic acid 18:1 (∆9) Lowers plasma LDL when substituted for
saturated fatty acids Linoleic acid 18:2 (∆9,12) Essential fatty acid and precursor of Arachidonic
acid Linolenic acid 18:3 (∆9,12,15) Essential fatty acid Arachidonic acid 20:4 (∆5,8,11,14) Precursor of most eicosanoids
![Page 18: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/18.jpg)
Saturated Fatty Acids
• Fatty acids with no double bonds• Solid at room temperature• Animal fats:
– Dairy: cheeses, ice cream, whole milk– Meat: beef, pork, lamb,– Plant/tropical oils (cottonseed, coconut)
• Stearic, lauric, myristic, palmitic
![Page 19: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/19.jpg)
Saturated Fatty Acid
![Page 20: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/20.jpg)
Trans Fatty Acids
• Essentially a saturated fat
• Raise LDL• Lower HDL
• Intake has increased dramatically – Found in margarine, cookies, potato chips, snack
chips, onion rings
• Current intake is~3% of total kcals
risk for heart disease
![Page 21: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/21.jpg)
Hydrogenation of Fatty Acids
• Process used to solidify an oil
• Addition of hydrogen to an unsaturated fatty acid (eliminating the double bond—making it into a saturated fatty acid)
• Trans fatty acids are a by product of hydrogenation
• How can we limit intake of these?
![Page 22: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/22.jpg)
Figure 06_07
![Page 23: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/23.jpg)
Trans Fatty Acid
![Page 24: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/24.jpg)
Food Labels
• % Daily Value on Nutrition Facts label is sum of trans and saturated fatty acids
• Quantity of trans fatty acids
• “Trans fat free” has no more than 0.5 g each of trans or saturated fat
• Read the food label and look for hydrogenated or partially hydrogenated oils, or trans fatty acids
![Page 25: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/25.jpg)
Trans Fatty Acids
![Page 26: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/26.jpg)
Monounsaturated Fatty Acids• One double bond
• Oleic acid (Omega 9)
• Olive oil, canola oil, nuts
• Rate of CHD low in Mediterranean countries where diet is rich in olive oil
• Diet high in MUFA equivalent to low-fat diet in ↓ LDL-C, but does not ↓ HDL-C
![Page 27: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/27.jpg)
Monounsaturated Fatty Acid
![Page 28: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/28.jpg)
Polyunsaturated Fatty Acids
• 2 or more double bonds
• Provides essential fatty acids (EFAs)– Omega 3– Omega 6
• Properties differ between these EFAs
![Page 29: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/29.jpg)
Polyunsaturated Fatty Acid
![Page 30: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/30.jpg)
Figure 06_11
![Page 31: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/31.jpg)
Essential Fatty Acids
• Polyunsaturated fatty acids• Body can only make double bonds after
the 9th carbon from the omega end• • Needed for
– immune function– vision– cell membranes– production of hormone-like compounds
![Page 32: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/32.jpg)
32
Essential Fatty Acid Needs
• Adequate Intake– Approximately 2-4 Tablespoons daily
• Deficiency– Unlikely
• Toxicity– No upper level set
![Page 33: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/33.jpg)
Omega-3 Fatty Acids
• Linolenic acid (α-linolenic acid)
• Forms eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)
• Metabolized to form eicosanoids
![Page 34: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/34.jpg)
![Page 35: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/35.jpg)
Omega-3 Fatty Acids
• Consumption of large amounts of omega-3 fatty acids decreases the ability of blood to clot
• May:– Prevent stroke and heart attacks caused by
clots (thrombosis)– Reduce risk of stroke caused by blood clots– Help some chronic inflammatory conditions
• Asthma, rheumatoid arthritis, psoriasis
![Page 36: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/36.jpg)
Omega-3 Fatty Acids– Recommend intake of ~2 servings of fish/wk– Shellfish
– Cold water/fatty fish (salmon, mackerel, sardines, tuna)
• Consumption of canola or olive oil vs. other plant oils
• Flaxseed oil– 2 tbsp per day
• Fish oil capsules– 900 mg per day– Avoid: if have a history of bleeding
disorder, on blood thinners
![Page 37: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/37.jpg)
Omega-6 Fatty Acids
• Linoleic acid
• Forms arachidonic acid
• Metabolized to eicosanoids
• Found in vegetable oils– Corn, sunflower, safflower, soybean oils, nuts,
seeds, wheat germ
• Only need ~ 1 tablespoon a day
![Page 38: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/38.jpg)
![Page 39: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/39.jpg)
Eicosanoids
• A group of hormone-like compounds
• By-pass the blood stream and work in the area of origin
• Regulators of:– Blood pressure– Clotting– Immune responses– Inflammatory responses– Stomach secretions
• Prostaglandins, thromboxanes, leukotrienes, prostacyclins, lipoxins
![Page 40: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/40.jpg)
Eicosanoids Have Different Effects
• Omega-3 eicosanoids, DHA, EPA – ↓ blood clotting– ↓ inflammatory responses– Reduce heart attack– Excess may cause hemorrhagic stroke
• Omega-6 eicosanoids; Arachidonic acid– ↑blood clotting– ↑ inflammatory responses
• Eicosanoids have different effects on different tissues
![Page 41: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/41.jpg)
![Page 42: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/42.jpg)
American Heart Association Recommendations
• Total fat: <30% of total calories
• Saturated fat: <10% of total calories
• Monounsaturated fat: 10% of total calories
• Polyunsaturated fat: 10% of total calories
• Cholesterol: <300 mg/day
![Page 43: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/43.jpg)
43
Phospholipids
• Hydrophobic and Hydrophillic Ends
• Functions– Component of cell membranes– Eicosanoid synthesis– Emulsifier
• Allows fats/lipids to be dispersed in water– Bile acids
• Sources– Synthesized by the body as needed– Built on a glycerol backbone
• At least one fatty acid replaced with phosphorus compound– Food: egg yolks (lecithin), wheat germ and peanuts
![Page 44: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/44.jpg)
Emulsifier
Hydrophilic end (attracts water)
Hydrophobic end (attracts lipid)
![Page 45: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/45.jpg)
45
![Page 46: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/46.jpg)
46
Sterols
• Multi-ringed structure, most known is cholesterol
• Functions– Bile acids, cell membranes– Precursor of steroid hormones, sex
hormones, adrenal hormones, Vitamin D
• Sources– Synthesized by the liver– Food: animal origin
![Page 47: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/47.jpg)
![Page 48: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/48.jpg)
Lipid Digestion
• Mouth– Lingual lipase (inactive until reaches stomach)
• Stomach– Gastric lipase (digests primarily SCFAs)– Muscular contractions mix fat with digestive
enzymes– Fats generally remain in stomach 2-4 hours
![Page 49: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/49.jpg)
Lipid Digestion
• Small intestine– Cholecystokinin (CCK) and Secretin
• Released due to presence of fat in duodenum
• CCK stimulates release of– Pancreatic lipase– Bile (to help emulsify fat)
• Secretin stimulates release of – Bicarbonate
» Raises pH for activation of lipases
![Page 50: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/50.jpg)
Bile• Composed of bile acids, bile pigments,
phospholipids (lecithin)
• Synthesized from cholesterol in the liver
• Function is to emulsify fat – Allows fat to be suspended in watery digestive juices– Large fat globules broken down to smaller ones,
surface area for lipase action increases – Micelles are formed
![Page 51: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/51.jpg)
Bile
• Once used for emulsification, can go through 1 of 2 routes:
– Reabsorbed in small intestine and recycled– Binds to fiber in large intestine and excreted
• This is how fiber (in particular soluble fiber) helps lower blood cholesterol levels
![Page 52: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/52.jpg)
Enterohepatic Circulation
![Page 53: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/53.jpg)
End Products of Lipid Digestion• Glycerol
• Fatty acids
• Cholesterol
• Lecithin
![Page 54: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/54.jpg)
Lipid Absorption
• Micelles– Emulsified fat droplets– Absorbed across intestinal mucosal cells by diffusion
• Distal duodenum, jejunum
• End products of dietary lipid digestion– Repackaged into chylomicrons– Released into lymph system
• Bile salts absorbed in the ileum– Returned to liver via portal vein to be reused – “Enterohepatic circulation”
![Page 55: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/55.jpg)
EmulsificationEmulsification
![Page 56: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/56.jpg)
![Page 57: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/57.jpg)
Lipid Transport
• Water (blood) and oil (fat) are incompatible
• Unique system of fat transportation needed for lipids to travel in bloodstream
![Page 58: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/58.jpg)
Lipid Transport
• Lipoproteins– Transport lipids through bloodstream– Composed of:
• Triglycerides, protein, phospholipids, cholesterol
– 4 different types• Chylomicrons• VLDL (Very-low density lipoprotein) • LDL (Low density lipoprotein)• HDL (High density lipoprotein)
![Page 59: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/59.jpg)
Lipoprotein
![Page 60: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/60.jpg)
Chylomicrons
• Large in size
• Triglyceride–rich (80-90% TG)
• Transport dietary (exogenous) fat to cells– High blood concentrations following a meal
• Transported via lymph system, enter bloodstream at thoracic duct
![Page 61: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/61.jpg)
Chylomicrons
• Lipoprotein lipase (LPL) breaks down TGs in chylos
• Fatty acids are absorbed by cells (muscle, adipose, etc.)
• Chylomicron remnants removed by the liver, broken down, and repackaged into VLDL– At this point, fats are considered ENDOGENOUS
• 2-10 hours to clear from bloodstream
![Page 62: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/62.jpg)
Dietary Fat Absorption
![Page 63: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/63.jpg)
Very-Low Density Lipoproteins• Triglyceride-rich (55-65%)
• Transports endogenous fats to cells– Lipids synthesized in liver
• Released from liver into bloodstream
![Page 64: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/64.jpg)
Very-Low Density Lipoproteins• Lipoprotein lipase (LPL) breaks down TGs in VLDL
• Fatty acids are absorbed by cells (muscle, adipose, etc.)
• VLDL remnants are removed by liver, broken down, and repackaged into LDL
• 10-12 hours to clear from bloodstream
![Page 65: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/65.jpg)
Low Density Lipoproteins
• Cholesterol-rich (45%)
• Transports cholesterol synthesized by liver
• Removed from bloodstream via receptors (or scavenger pathway)– Receptors down-regulated with high saturated/trans
fatty acid diet
• 2-3 days to clear from bloodstream
![Page 66: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/66.jpg)
Low Density Lipoproteins
Optimal <100 mg/dl
Factors that raise LDL
• High saturated fat diet
• Diet high in trans fatty acids
• Low fiber diet
• Sedentary lifestyle
![Page 67: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/67.jpg)
High Density Lipoproteins
• Protein rich (45-50%)• Synthesized by liver and intestine• Picks up cholesterol from dying cells and
other sources• Transfer cholesterol to other lipoproteins
for transport to liver for excretion• HDL can also transfer directly back to the
liver
![Page 68: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/68.jpg)
Benefits of High HDL• Removes cholesterol from blood
• May block oxidation of LDL
• Reduces risk of heart disease
• Pre-menopausal women have higher HDL
![Page 69: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/69.jpg)
High Density Lipoproteins
Desirable >60 mg/dl
Factors that raise HDL Low saturated fat dietReplacing saturated fats with Mono - unsaturated fatsExercise
45 minutes 4 times a weekLosing excess weight, if overweight
Moderateoderate amount of alcohol
![Page 70: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/70.jpg)
Lipoproteins
![Page 71: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/71.jpg)
Composition of Lipoproteins
![Page 72: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/72.jpg)
Metabolism of Lipids
• Fatty acids, monoglycerides and other lipids taken up by tissue cells
• Can be used in 1 of 4 ways:– Immediate source of energy– Energy storage (adipose)– Incorporation into cell membranes– Used as raw material for synthesis of
essential compounds (cholesterol)
![Page 73: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/73.jpg)
Lipids as an Energy Source
• Hormone sensitive lipase (HSL)– Enzyme found in liver and adipose tissue
– Key enzyme for lipolysis of stored fat
– Insulin inhibits HSL (inhibits lipolysis)– Glucagon activates HSL (leads to lipolysis)
![Page 74: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/74.jpg)
Lipids as Stored Energy
• Unlimited capacity for fat storage
• Lipoprotein lipase (LPL)– Located in adipose and muscle cells– Facilitates uptake of FA from blood– Excess energy intake
LPL synthesis fat stored in adipose
![Page 75: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/75.jpg)
Health Implications of Fat
• Cardiovascular disease– Major cause of morbidity and mortality in US– >500,000 people die every year– ~1.5 million Americans have a heart attack every year
• Obesity– Fat is a concentrated source of calories– Abdominal fat associated with risk for DM and HTN
• Cancer– High fat diet associated with certain forms of cancer
![Page 76: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/76.jpg)
Heart Disease• Cardiovascular Disease (CVD)
– Disease of the heart and blood vessels
• Coronary Heart Disease (CHD)– Damage that occurs when blood vessels carrying blood to the
heart (the coronary arteries) become narrow and occluded– Leading cause of death in US
• Myocardial infarction (MI)– Accounts for ~50% of CVD deaths– Major underlying cause is atherosclerosis
![Page 77: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/77.jpg)
Development of CHD• When blood flow via coronary arteries is interrupted
• Heart attack (myocardial infarction) may result leading to– Irreversible damage to heart muscle– Irregular heart beat or stopped heartbeat– 25% of people do not survive their 1st MI
• Cerebrovascular accident (CVA) or stroke – When blood flow to part of brain is interrupted causing
part of brain to die
![Page 78: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/78.jpg)
Myocardial Infarction (MI)
![Page 79: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/79.jpg)
Signs of a Heart Attack
• Intense, prolonged chest pain• Shortness of breath• Sweating• Nausea and vomiting• Dizziness• Weakness• Jaw, neck, shoulder pain• Irregular heartbeat
![Page 80: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/80.jpg)
Risk Factors for Heart Disease
Modifiable• Smoking• Hyperlipidemia
– Total Chol >200 mg/dL– Low HDL-C <35 mg/dL– Hight LDL-C
• Obesity• HTN• Physical Inactivity• Diabetes Mellitus
Non-Modifiable• Age
– Male >45– Female >55
• Male gender• Family history of CHD
![Page 81: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/81.jpg)
Other Risk Factors• Serum Homocysteine
– Amino acid– High level in blood associated with increased
risk of MI– Causes damage to blood vessel wall
• Reduce blood level by:– Increasing folate, B6 and B12 intake
• Fruits, vegetables, etc.
![Page 82: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/82.jpg)
Other Risk Factors
• C-Reactive Protein (CRP)– Acute phase protein that increases during systemic
inflammation– Levels in blood increase during inflammation– Biochemical marker for CVD
![Page 83: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/83.jpg)
National Heart Lung and Blood Institute, Adult Treatment Panel III Guidelines for
CHD (2001)
LDL Cholesterol <100 Optimal 100-129 Near optimal 130-159 Borderline high 160-189 High >190 Very high Total Cholesterol <200 Desirable 200-239 Borderline high >240 High HDL Cholesterol <40 Low >60 High
![Page 84: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/84.jpg)
Reduce Your Risk (Primary Prevention)
• ↓ dietary saturated fat, trans fatty acid, and cholesterol
• ↑ MUFA and PUFA to recommended amounts• ↑ dietary fiber• Maintain healthy weight• Don’t smoke• Alcohol in moderation• Folate intake• Low glycemic index load
![Page 85: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/85.jpg)
Secondary Prevention (After a Heart Attack)
• Primary prevention techniques
• Medication
• Megadoses of vitamin E (400-800 IU/day)
![Page 86: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/86.jpg)
Therapeutic Lifestyle Changes
• Total Fat 25-35% of total kcals
• SFA <7% of total kcals
• MUFA Up to 20% “ “
• PUFA Up to 10% “ “
• CHO 50-60% of “ “
• Protein 10-20% of “ “
• Cholesterol <200 mg/d
• Fiber 20-30 g/d
![Page 87: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/87.jpg)
Therapeutic Lifestyle Changes
• Other recommendations:– Plant stanols/sterols
• 2 g/d
– Kcals• To maintain optimal weight, prevent weight gain
– Physical activity• Expend at least 200 kcal/d
![Page 88: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/88.jpg)
Medical Therapy
• Statin drugs– Lipitor, Zocor, Mevacor, etc.– Successful in reducing blood cholesterol
• Benecol and Take Control– Plant stanol ester– Cholesterol-lowering effect– Compete with cholesterol in the micelle and reduce
absorption of dietary cholesterol
![Page 89: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/89.jpg)
Medical Therapy
• Surgical Intervention– Angioplasty– Coronary Artery Bypass Graft (CABG)
![Page 90: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/90.jpg)
Angioplasty
![Page 91: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/91.jpg)
Stent placement
![Page 92: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/92.jpg)
![Page 93: Chapter 6: Lipids](https://reader035.vdocuments.site/reader035/viewer/2022062304/56812be0550346895d905157/html5/thumbnails/93.jpg)
CABG surgery