The LipidsThe Lipids

Introduction to LipidsIntroduction to Lipids

Lipids – water Lipids – water insoluble component insoluble component of cellsof cells HydrophobicHydrophobic Made of the elements: Made of the elements:

• CarbonCarbon• HydrogenHydrogen• OxygenOxygen• Phosphorus (in Phosphorus (in

phospholipids only)phospholipids only)

Introduction to LipidsIntroduction to Lipids

Classes of lipids:Classes of lipids: Triglycerides and Triglycerides and

fatty acidsfatty acids• Triglycerides are the Triglycerides are the

fats we eatfats we eat• 9 kcal/gram9 kcal/gram

PhospholipidsPhospholipids• Also 9 kcal/gramAlso 9 kcal/gram

SteroidsSteroids

IntakeIntake

Recommended levels Recommended levels of intake:of intake: 20-35 % daily kcal 20-35 % daily kcal

from fats (triglycerides)from fats (triglycerides)• Maximum 10% from Maximum 10% from

saturated fatssaturated fats

Maximum 300 mg Maximum 300 mg cholesterol per daycholesterol per day

• No or lower cholesterol No or lower cholesterol intake is fine/goodintake is fine/good

TriglyceridesTriglycerides 3 carbon backbone (called glycerol) 3 carbon backbone (called glycerol)

with 3 fatty acids (FA) attached with 3 fatty acids (FA) attached • Nature of the attached fatty acid Nature of the attached fatty acid

determines the properties of the determines the properties of the triglyceridetriglyceride

TriglycerideTriglyceride

Fatty AcidsFatty Acids

Fatty Acids - structureFatty Acids - structure Long hydrocarbon Long hydrocarbon

chainschains Most are 4-24 carbons Most are 4-24 carbons

longlong• Always an even Always an even

number of carbonsnumber of carbons Carbon chains differ Carbon chains differ

in:in:• LengthLength• Points of unsaturationPoints of unsaturation

Fatty AcidsFatty Acids

Saturated Fatty AcidsSaturated Fatty Acids All carbon to carbon single bondsAll carbon to carbon single bonds

• Chain is Chain is saturatedsaturated with hydrogens with hydrogens Chain is relatively straightChain is relatively straight

Fatty AcidsFatty Acids

Unsaturated Fatty Unsaturated Fatty AcidsAcids At least one C to C At least one C to C

double bond presentdouble bond present Double bonds Double bonds

kink/bend the chainkink/bend the chain

Fatty AcidsFatty Acids

Monounsaturated FAMonounsaturated FA One C to C double One C to C double

bondbond

PolyunsaturatedPolyunsaturated More than one C to C More than one C to C

double bonddouble bond

TriglyceridesTriglycerides

Fatty acids may Fatty acids may differdiffer Nature of fatty Nature of fatty

acids impacts acids impacts properties of the properties of the triglyceridetriglyceride

Saturated FatsSaturated Fats Triglycerides with Triglycerides with

primarily saturated fatty primarily saturated fatty acids:acids:

Solid Solid Primarily from animal Primarily from animal

sourcessources• Plant sources include Plant sources include

palm and coconut oilpalm and coconut oil More stable than More stable than

Triglycerides with Triglycerides with unsaturated FAunsaturated FA

• Store betterStore better• Taste better!Taste better!• Associated with health Associated with health

risks risks

Unsaturated FatsUnsaturated Fats

Triglycerides with Triglycerides with primarily unsaturated primarily unsaturated fatty acids are:fatty acids are: Liquids (oils)Liquids (oils) Primarily from plant Primarily from plant

sourcessources Double bonds are Double bonds are

reactivereactive• Therefore plant oils Therefore plant oils

react with oxygen and react with oxygen and go rancid easilygo rancid easily

Food Sources Food Sources Saturated FatsSaturated Fats Butter, cream, milk, Butter, cream, milk,

cheesecheese Red meatRed meat Chicken and fish are a Chicken and fish are a

mixture of sat’d and mixture of sat’d and unsat’d fatsunsat’d fats

Sources of Sources of Unsaturated FatsUnsaturated Fats MonounsaturatedMonounsaturated

• Olive oil, canola oil, Olive oil, canola oil, peanut oilpeanut oil

PolyunsaturatedPolyunsaturated• Corn oil, soybean oil, Corn oil, soybean oil,

sunflower oil…..sunflower oil…..

Fatty AcidsFatty Acids

Essential Fatty Essential Fatty Acids Acids Omega-3 FA => Omega-3 FA =>

double bond 3 C double bond 3 C from the end from the end

• May lower May lower cholesterol and risk cholesterol and risk of heart disease, of heart disease, hypertension, ?hypertension, ?cancer, ?arthritiscancer, ?arthritis

• Good food sources: Good food sources: fish, soy, nuts, many fish, soy, nuts, many oilsoils

TriglycerideTriglyceride

HydrogenationHydrogenation

Hydrogenation Hydrogenation reactionreaction

Adds hydrogens to Adds hydrogens to double bondsdouble bonds

Removes “kinks” Removes “kinks” from fatty acid from fatty acid chainschains

• Fully Fully hydrogenated fats hydrogenated fats have the same have the same health issues as health issues as natural sources of natural sources of saturated fatssaturated fats

HydrogenationHydrogenation

Partially Partially hydrogenated hydrogenated triglyceridestriglycerides Often the remaining Often the remaining

double bonds double bonds converted from converted from ciscis to to transtrans form form

• Cis form is the naturally Cis form is the naturally occurring formoccurring form

• Trans fatty acids are Trans fatty acids are associated with health associated with health risksrisks

Cis and Trans Fatty acidsCis and Trans Fatty acids

PhospholipidsPhospholipids

Function: structural Function: structural component of all cell component of all cell membranesmembranes

Structure:Structure: Glycerol backbone Glycerol backbone

(3 carbons) with 2 (3 carbons) with 2 fatty acids attached fatty acids attached and one phosphate and one phosphate group group

Attached to the Attached to the phosphate group is phosphate group is some other groupsome other group

SteroidsSteroids

Structure: 4 linked Structure: 4 linked carbon rings with side carbon rings with side chainschains

Examples of steroids Examples of steroids (we make in body)(we make in body) CholesterolCholesterol Vitamin DVitamin D Bile saltsBile salts Sex hormonesSex hormones

Transport of lipids in Blood StreamTransport of lipids in Blood Stream

Low density lipoprotein Low density lipoprotein (LDL)(LDL)

LDL is high in LDL is high in cholesterolcholesterol

LDL circulates in blood LDL circulates in blood looking for cells that looking for cells that need cholesterolneed cholesterol

• Also picks up Also picks up cholesterol from other cholesterol from other lipoproteinslipoproteins

TransportTransport

LDLLDL ““Bad” cholesterolBad” cholesterol Contributes to plaques Contributes to plaques

when cholesterol “falls when cholesterol “falls off” the LDL and is off” the LDL and is deposited on artery deposited on artery wallswalls

Plaques narrow Plaques narrow arteriesarteries

• Raises blood pressureRaises blood pressure• Increases risk of blood Increases risk of blood

clots and heart attacksclots and heart attacks

TransportTransport

HDLHDL High density High density

lipoproteinlipoprotein HDL transports HDL transports

cholesterol and other cholesterol and other lipids back to liver for lipids back to liver for disposaldisposal

• Can pick up cholesterol Can pick up cholesterol from plaquesfrom plaques

• Good cholesterolGood cholesterol

CholesterolCholesterol

Maximum level of Maximum level of intake recommendedintake recommended 300 mg/day300 mg/day Make all we need, so Make all we need, so

no intake is fineno intake is fine Food Sources – all Food Sources – all

animal animal (no plant sources)(no plant sources) Egg yolkEgg yolk Dairy (unless fat removed Dairy (unless fat removed

as in skim milk)as in skim milk) Meat, poultryMeat, poultry

Lowering Cholesterol LevelsLowering Cholesterol Levels

1.1. Reduce intake of:Reduce intake of:• Saturated fatsSaturated fats• Trans fatty acidsTrans fatty acids• CholesterolCholesterol• Sugars (if sugar Sugars (if sugar

sensitive)sensitive)

2.2. Increase intake of:Increase intake of:• soluble fibers (oats soluble fibers (oats

and legumes)and legumes)• fishfish

Lowering Cholesterol LevelsLowering Cholesterol Levels

3.3. Moderate alcohol Moderate alcohol intake intake

4.4. Exercise – aerobic Exercise – aerobic may be bestmay be best

5.5. Lose weightLose weight