The Lipids. Introduction to Lipids Lipids – water insoluble component of cells Hydrophobic Hydrophobic Made of the elements: Made of the elements: CarbonCarbon.
Post on 30-Dec-2015
218 Views
Preview:
Transcript
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
top related