LipidsLipids
LipidsLipids
Do not readily dissolve in waterDo not readily dissolve in water
Types of lipids:Types of lipids:– TriglyceridesTriglycerides– PhospholipidsPhospholipids– Sterols (Cholesterol)Sterols (Cholesterol)
Fats (solid) and oils (liquid)Fats (solid) and oils (liquid)– 9 kcal /gm9 kcal /gm
Chemical Forms of Common Chemical Forms of Common LipidsLipids
Fatty AcidsFatty Acids
Found in our body and foodsFound in our body and foods– In triglycerides In triglycerides
Saturated fatty acidsSaturated fatty acids– Solid formSolid form
Unsaturated fatty acidsUnsaturated fatty acids– Liquid formLiquid form
Fats are composed of both saturated Fats are composed of both saturated and unsaturated fatty acidsand unsaturated fatty acids
Fatty Acid Structure Fatty Acid Structure
omega endomega end alpha alpha endend
Degree of saturationDegree of saturation
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
Saturated Fatty Acid Saturated Fatty Acid StructureStructure
omega endomega end alpha endalpha end
Degree of saturation: single carbon bondDegree of saturation: single carbon bond
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
Monounsaturated Fatty Acid Monounsaturated Fatty Acid StructureStructure
omega endomega end alpha alpha endend
One double bondOne double bond
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
Polyunsaturated Fatty Acid Polyunsaturated Fatty Acid StructureStructure
omega endomega end alpha alpha endend
>> 2 double bonds 2 double bonds
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
Composition of Common Fats / Composition of Common Fats / OilsOils
Essential Fatty AcidsEssential Fatty Acids
Omega-3 fatty acid (alpha-linolenic acid)Omega-3 fatty acid (alpha-linolenic acid) Omega-6 fatty acid (linoleic acid)Omega-6 fatty acid (linoleic acid) Body can only make double bonds after Body can only make double bonds after
the 9th carbon from the omega endthe 9th carbon from the omega end FunctionsFunctions
– Immune function, vision, cell membrane, Immune function, vision, cell membrane, and production of hormone-like compoundsand production of hormone-like compounds
TriglyceridesTriglycerides
Most common form of fats and oils in Most common form of fats and oils in our body & in the foods we eatour body & in the foods we eat
Fatty acids attached to a glycerolFatty acids attached to a glycerol
Triglycerides Triglycerides
Glycerol + 3 FA’s Triglyceride +Glycerol + 3 FA’s Triglyceride +
3 H3 H2200
PhospholipidsPhospholipids
Built on a glycerol backboneBuilt on a glycerol backbone Contains phosphorus compound(s)Contains phosphorus compound(s) Found in bodyFound in body Synthesized by the body as neededSynthesized by the body as needed
Functions of PhospholipidsFunctions of Phospholipids
Component of cell membraneComponent of cell membrane EmulsifierEmulsifier
– Bile acidsBile acids– LecithinsLecithins– Improves food productsImproves food products
Found in wheat germ, peanuts, Found in wheat germ, peanuts, yolks, soy beans, organ meatyolks, soy beans, organ meat
SterolsSterols
Multi-ringed structureMulti-ringed structure Do not have a glycerol backboneDo not have a glycerol backbone Cholesterol is a sterolCholesterol is a sterol Waxy substanceWaxy substance Do not readily dissolve in waterDo not readily dissolve in water Found in animal foodsFound in animal foods
Functions of CholesterolFunctions of Cholesterol
Essential component of cell Essential component of cell membranemembrane
Produced by the liverProduced by the liver Found only in animal productsFound only in animal products Forms important hormonesForms important hormones
– Estrogen, testosterone, vitamin DEstrogen, testosterone, vitamin D
Precursor to bile acidsPrecursor to bile acids
Lipids in FoodsLipids in Foods
EmulsifiersEmulsifiers
Hidden FatHidden Fat
Look on the Nutrition Facts labelsLook on the Nutrition Facts labels Look on the lists of ingredientsLook on the lists of ingredients Control portion sizeControl portion size
Reduced-Fat FoodsReduced-Fat Foods
Calorie content is about the sameCalorie content is about the same Sugar is commonly added in place of Sugar is commonly added in place of
fatfat
Fat SubstitutesFat Substitutes Water Water
– Diet margarineDiet margarine Z-trim Z-trim
– Starch derivative that binds with waterStarch derivative that binds with water Fiber cellulose Fiber cellulose
– Maltrin, Stellar, OatrimMaltrin, Stellar, Oatrim Dairy-Lo Dairy-Lo
– Protein globulesProtein globules Olestra or Olean (links fatty acid to Olestra or Olean (links fatty acid to
sucrose)sucrose)– Not digestedNot digested– FDA approved for fried snack foods FDA approved for fried snack foods – Fat-soluble vitamins issueFat-soluble vitamins issue
RancidityRancidity
Decomposed oilsDecomposed oils Breakdown of the C=C bonds by Breakdown of the C=C bonds by
UV light, and/or OUV light, and/or O22
Unpleasant odor and flavorUnpleasant odor and flavor PUFA more susceptible PUFA more susceptible Limited shelf lifeLimited shelf life
Prevention of RancidityPrevention of Rancidity
HydrogenationHydrogenationAddition of vitamin EAddition of vitamin EAddition of Butylated Addition of Butylated
hydroxyanisol (BHA) and hydroxyanisol (BHA) and Butylated hydroxytolune Butylated hydroxytolune (BHT)(BHT)
Hydrogenation of Fatty Hydrogenation of Fatty AcidsAcids
Process used to solidify an oilProcess used to solidify an oil Addition of H to C=C double Addition of H to C=C double
bondsbonds Increases shelf lifeIncreases shelf life Formation of Formation of transtrans fatty acid fatty acid
– (similar to shape of saturated fatty (similar to shape of saturated fatty acid)acid)
HydrogenationHydrogenation
Cis and Cis and TransTrans Fatty Acid Fatty Acid
Excessive Excessive TransTrans Fatty Acid Fatty Acid IntakeIntake
Raises LDLRaises LDL Lowers HDLLowers HDL Increases risk for Increases risk for
cardiovascular diseasecardiovascular disease Current intake is 3%-4% of Current intake is 3%-4% of
total kcaltotal kcal Added to food labels Jan. ‘06Added to food labels Jan. ‘06
Typical Sources of Typical Sources of TransTrans Fat Fat
Minimize Intake of Minimize Intake of TransTrans Fat Fat
Limit use of hydrogenated Limit use of hydrogenated fatsfats
Limit deep-fried foodsLimit deep-fried foodsLimit high-fat baked goodsLimit high-fat baked goodsLimit use of non-dairy Limit use of non-dairy
creamerscreamers
Digestion of Fats and OilsDigestion of Fats and Oils
Digestion of Fat in the Digestion of Fat in the StomachStomach
Gastric lipaseGastric lipase – Activated by an acidic environment Activated by an acidic environment – Acts on triglycerides containing Acts on triglycerides containing
short- and medium-chain fatty short- and medium-chain fatty acidsacids
Digestion of Fat in the Small Digestion of Fat in the Small IntestineIntestine
Primary site of fat digestionPrimary site of fat digestion Hormone Cholecystokinin (CCK) Hormone Cholecystokinin (CCK)
– Stimulates release of pancreatic lipaseStimulates release of pancreatic lipase Bile acid releasedBile acid released
– Emulsifies digested fatEmulsifies digested fat Fat is broken downFat is broken down
– To monoglycerides and fatty acidsTo monoglycerides and fatty acids
Absorption of FatAbsorption of Fat
95% of dietary fat is absorbed95% of dietary fat is absorbed Diffused into the absorptive cellsDiffused into the absorptive cells Short- and medium-chain (<12 C) Short- and medium-chain (<12 C)
fatty acids fatty acids – Are water solubleAre water soluble– Enter the portal systemEnter the portal system
Long-chain fatty acids re-form into Long-chain fatty acids re-form into triglyceridestriglycerides– Not water solubleNot water soluble– Enter the lymphatic system Enter the lymphatic system
Carrying Fat in the Carrying Fat in the BloodstreamBloodstream
Water (blood) and oil (fat) are Water (blood) and oil (fat) are incompatibleincompatible
Unique system of fat transportation Unique system of fat transportation is neededis needed
Transportation of Absorbed Transportation of Absorbed Fatty AcidsFatty Acids
Re-formed into triglyceridesRe-formed into triglycerides Packaged into chylomicronsPackaged into chylomicrons Lipoprotein lipase Lipoprotein lipase
– Breaks down triglycerides in the Breaks down triglycerides in the chylomicronschylomicrons
Chylomicron remnant Chylomicron remnant – Delivered to the liverDelivered to the liver
LipoproteinsLipoproteins
Composition and Roles of Composition and Roles of LipoproteinsLipoproteins
Transportation of Transportation of Synthesized FatSynthesized Fat
Made primarily by the liverMade primarily by the liver Very-Low-Density Lipoprotein (VLDL)Very-Low-Density Lipoprotein (VLDL) Low-Density Lipoprotein (LDL)Low-Density Lipoprotein (LDL) High-Density Lipoprotein (HDL)High-Density Lipoprotein (HDL)
High-Density Lipoprotein High-Density Lipoprotein (HDL)(HDL)
Synthesized by liver and intestineSynthesized by liver and intestine High proportion of protein High proportion of protein Picks up cholesterol from dying cells Picks up cholesterol from dying cells
and other sourcesand other sources Transfers cholesterol to other Transfers cholesterol to other
lipoproteins lipoproteins Transfers cholesterol directly back to Transfers cholesterol directly back to
the liverthe liver
Benefits of (a high) HDL Benefits of (a high) HDL (level)(level)
Removes cholesterol from the Removes cholesterol from the bloodstreambloodstream
HDL may block oxidation of LDLHDL may block oxidation of LDL Reduces risk of cardiovascular Reduces risk of cardiovascular
diseasedisease Pre-menopausal women have Pre-menopausal women have
higher HDLhigher HDL
Scavenger WBC removes Scavenger WBC removes (oxidized) LDL from circulation(oxidized) LDL from circulation
Build-up of plaque on walls of the Build-up of plaque on walls of the blood vesselsblood vessels
Development of atherosclerosisDevelopment of atherosclerosis Vessel damage caused by: Vessel damage caused by:
– Smoking, diabetes, hypertension, Smoking, diabetes, hypertension, homocysteine, high LDL, infectionhomocysteine, high LDL, infection
Scavenger Cells Scavenger Cells
AntioxidantAntioxidant
Reduces oxidationReduces oxidation Slows LDL uptake by scavenger Slows LDL uptake by scavenger
cellscells
Functions of Essential Functions of Essential Fatty AcidsFatty Acids
Essential Fatty Acid- Omega-3 Essential Fatty Acid- Omega-3 (alpha-linolenic acid)(alpha-linolenic acid)
omega endomega end alpha endalpha end
1st double bond is located on the 3rd 1st double bond is located on the 3rd carbon from the omega endcarbon from the omega 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
Omega-3 Fatty AcidOmega-3 Fatty Acid
Primarily from fish oilPrimarily from fish oil Also found in canola, walnuts, Also found in canola, walnuts,
flax seeds, mussels, crab, flax seeds, mussels, crab, shrimp, and soybean oilshrimp, and soybean oil
Recommended intake of ~2 Recommended intake of ~2 servings of fish per weekservings of fish per week
Essential Fatty Acid- Omega-6 Essential Fatty Acid- Omega-6 (alpha-linoleic acid)(alpha-linoleic acid)
omega endomega end alpha endalpha end
1st double bond is located on the 6th 1st double bond is located on the 6th carbon from the omega endcarbon from the omega end
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
Omega-6 Fatty AcidOmega-6 Fatty Acid
Found in vegetable oilsFound in vegetable oils Only need Only need
~ 2-4 tablespoons a day ~ 2-4 tablespoons a day
Health-related EffectsHealth-related Effects
Archidonic acid (Omega-6 )Archidonic acid (Omega-6 )– Increases blood clottingIncreases blood clotting– Increases inflammatory responsesIncreases inflammatory responses
DHA, EPA (Omega-3)DHA, EPA (Omega-3)– Decrease blood clottingDecrease blood clotting– Reduce heart attackReduce heart attack– Decrease inflammation Decrease inflammation – Excess may cause hemorrhagic strokeExcess may cause hemorrhagic stroke– Other possible uses: Lower triglycerides, Other possible uses: Lower triglycerides,
rheumatoid arthritis, behavioral rheumatoid arthritis, behavioral disordersdisorders
Signs and Symptoms of Signs and Symptoms of Essential Fatty Acids Essential Fatty Acids
DeficiencyDeficiency
Flaky, itchy skinFlaky, itchy skin DiarrheaDiarrhea InfectionsInfections Retarded growth and wound Retarded growth and wound
healinghealing
Functions of Fatty Acids Functions of Fatty Acids
Provide energyProvide energy Efficient storage of energyEfficient storage of energy InsulationInsulation ProtectionProtection Transport fat-soluble vitaminsTransport fat-soluble vitamins Some satietySome satiety Flavor and mouth feelFlavor and mouth feel
Recommendations for Fat Recommendations for Fat IntakeIntake
No RDA No RDA AHA recommendationsAHA recommendations
– 20-30% of total kcal from fat20-30% of total kcal from fat– 7-10% can come from saturated/7-10% can come from saturated/transtrans fat fat– 200-300 mg cholesterol/day200-300 mg cholesterol/day
Average U.S. intake:Average U.S. intake:– 33% of total kcal from fat33% of total kcal from fat– 13% of kcal from saturated fat13% of kcal from saturated fat– 180-320 mg cholesterol/day180-320 mg cholesterol/day
AHA GoalsAHA Goals
AHA RecommendationsAHA Recommendations
Advice from National Advice from National Cholesterol Education Cholesterol Education Program and Food and Program and Food and
Nutrition Board Nutrition Board Up to 35% of total kcal from fatUp to 35% of total kcal from fat Keep saturated fat, cholesterol, Keep saturated fat, cholesterol,
and and transtrans fat to a minimum fat to a minimum
Other RecommendationsOther Recommendations
Fat intake can be higher as long as Fat intake can be higher as long as saturated and saturated and transtrans fatty acid are fatty acid are minimalminimal
Eat plenty of fruits and vegetablesEat plenty of fruits and vegetables Cut down on red meatsCut down on red meats Cut down on simple sugars and Cut down on simple sugars and
refined carbohydraterefined carbohydrate Promote healthy weightPromote healthy weight Be activeBe active
Cutting the FatCutting the Fat
Road to a Heart AttackRoad to a Heart Attack
Cardiovascular DiseaseCardiovascular Disease
Myocardial infarctionMyocardial infarction Cerebrovascular diseaseCerebrovascular disease
Risk FactorsRisk Factors
Total blood cholesterol > 200 mg/dlTotal blood cholesterol > 200 mg/dl Smoking Smoking
– Increases clottingIncreases clotting– Increases expression of genetic linkIncreases expression of genetic link
Hypertension (> 139/89)Hypertension (> 139/89) DiabetesDiabetes
– Insulin increases cholesterol synthesisInsulin increases cholesterol synthesis– Guarantees development of Guarantees development of
cardiovascular diseasecardiovascular disease
Other Risk FactorsOther Risk Factors
Low HDL (< 40 mg/dl)Low HDL (< 40 mg/dl) AgeAge Family historyFamily history Blood triglycerides > 200 mg/dlBlood triglycerides > 200 mg/dl Obesity Obesity
– Fat around the waistFat around the waist– Insulin resistanceInsulin resistance
InactivityInactivity
Signs of a Heart AttackSigns of a Heart Attack
Intense, prolong chest painIntense, prolong chest pain Shortness of breathShortness of breath SweatingSweating Nausea and vomitingNausea and vomiting DizzinessDizziness WeaknessWeakness Jaw, neck, shoulder painJaw, neck, shoulder pain Irregular heartbeatIrregular heartbeat
Medical Intervention Medical Intervention
For those who experience a heart For those who experience a heart attackattack– Or have CVD or diabetesOr have CVD or diabetes
www.nhlbi.nih.gov/guidelines/cholestewww.nhlbi.nih.gov/guidelines/cholesterol/index/htmrol/index/htm
Medication to lower LDLMedication to lower LDL– Reduce cholesterol synthesis (Statins, Reduce cholesterol synthesis (Statins,
“Lipitor”)“Lipitor”)– Binds to bile acids for eliminationBinds to bile acids for elimination
Medication to lower blood triglycerides Medication to lower blood triglycerides – Reduce triglyceride synthesisReduce triglyceride synthesis
Lowering LDLLowering LDL
See your doctor to assess for other See your doctor to assess for other conditionsconditions
Reduce dietary saturated fat and Reduce dietary saturated fat and cholesterolcholesterol
Increase MUFA and PUFAIncrease MUFA and PUFA Increase dietary fiber (soluble)Increase dietary fiber (soluble)
Lowering Blood TGLowering Blood TG
Is the most diet-responsive blood Is the most diet-responsive blood lipidlipid
Avoid overeatingAvoid overeating Limit alcoholLimit alcohol Limit simple sugarsLimit simple sugars Small frequent mealsSmall frequent meals Include fish in the dietInclude fish in the diet
Other Possible MethodsOther Possible Methods
BenecolBenecol and and Take Control Take Control margarinesmargarines– Plant stanol/sterol estersPlant stanol/sterol esters– Cholesterol-lowering effectsCholesterol-lowering effects– Decrease absorption of cholesterol and Decrease absorption of cholesterol and
lower amount returning via lower amount returning via enterohepatic circulationenterohepatic circulation
– Liver takes up more cholesterol from Liver takes up more cholesterol from the bloodthe blood
Raising HDLRaising HDL
Physical activityPhysical activity At least 45 min/day, 4 days a weekAt least 45 min/day, 4 days a week Don’t smokeDon’t smoke Eat regularly Eat regularly Eat less total fatEat less total fat Moderate intake of alcohol increases Moderate intake of alcohol increases
HDL HDL