LIPIDS:
• 1) Fats =
• 2) Oils =
Functions of Lipids:
• 1)
• 2)
• 3)
• 4)
• 5)
• 6)
Types of Lipids:
• 1) Triacylglycerols: (triglycerides, TG’s)
• 2) Phospholipids:
• 3) Isoprenoids:
3 Types of Fatty Acids:
• 1)
• 2)
• 3)
Chain Length
• 2-6 C’s =
• 8-10 C’s =
• 12 or more C’s =
H H H
H
H
H
H
H
H
H
H
H H
H H
H O
H3C18 C17 C16 C15 C14 C13 C12 C11 C10 C9 C8 C 7 C6 C5 C4 C3 C2 C1 OH
H H H H H H H H H H H H H H H H
Saturated Fatty Acid (SFA)
MUFA’s
H H
H
H
H
H
H
H
H
H
H H
H H
H H O
H3C18 C17 C16 C15 C14 C13 C12 C11 C10 C9 C8 C7 C6 C5 C4 C3 C2 C1 OH
H H H H H H H
H H H H H H H
PUFA’s
H H
H
H
H
H
H
H
H
H
H H
H H
H H O
H3C18 C17 C16 C15 C14 C13 C12 C11 C10 C9 C 8 C 7 C6 C5 C 4 C3 C2 C1 OH
H H H H
H
H H H H H H H
 or n
Further Classification of PUFA’s
• Omega 3 (-3)
vs.
Omega 6 (-6)
Linoleic Acid =
H H
H
H
H
H
H
H
H
H
H H
H H
H H O
H3C C C
H H
C
C
C
C
C
C
C
C
C
C
C
H
H
H
H H
H H
H H
H H
H
H
H
H
H
H
H
H
H H
H H
H H O
H3C C C
H
C
C
C
C
C
C
C
C
C
C
C
H
H H
H
C
C
C
C
OH
 end
H
H
a- Linolenic Acid =
C
C
H H
C
H H
C
OH
Synthesizing a FattyAcid:
• The body can synthesize all the fatty acids it
needs from dietary CHO, fat and protein
except for:
ESSENTIAL FATTY ACIDS:
1)
2)
-6 series

18:2-6
-3 series
18:3-3
 6 desaturase
18:3-6
18:4-3
elongase
20:3-6
20:4-3
 desaturase
20:4-6
(arachidonic
acid)
20:5-3
(EP A)
elongase
22:4-6
22:5-3
 6 desaturase
 desaturase
22:5-6
24:5-3
22:6-3
(DHA)
oxidase
24:6-3
Fatty Acid Synthesis
• Not all steps are equally efficient in
humans, elongation and desaturation of
18:3-3 to EPA and DHA appear somewhat
restricted in humans.
•
-3 and -6 f.a.’s that we eat become a
part of the phospholipids of our cell
membranes.
Effects of eicosanoid families:
• 1) Raise or lower BP (vasoconstrict or vasodilate
• 2) Increase or decrease platelet aggregation (bld.
Clotting)
• 3) Increase or decrease immune response
• 4) Increase or decrease inflammatory response
(asthma, arthritis)
Hydrogenation:
• Can chemically alter a MUFA or PUFA -->
H H
H
H
H
H
H
H
H
H
H H
H H
H H O
H3C C C
H
C
C
C
C
C
C
C
C
C
C
C
H
H H
H
H
a polyunsaturated fatty acid -
H H
H
H
H
H
H
H
H
H
H H
C
H H
C
C
OH
H H
a-linolenic acid
Add
Hydrogen
H H O
H H
C
H3C18 C17 C16 C15 C14 C13 C12 C11 C10 C 9 C 8 C 7 C 6 C5 C 4 C3 C2 C1 OH
H H H H H H H H H H H H H H H H
H3C
H3C
H H H
H
H
H
H
C
C
C
C
C
C
C
H H H
H
H
H
H
H
C
H H H
H
C
C
C
C
H H H
H
H
C
H
H
H
H H
H H
H O
C
C
C
C
C
C
C
H
H
H H
H H
H
C
C OH
H
H
H
H
H
H
H H
H H
H O
C
C
C
C
C
C
C
C
C
C
H
H
H H
H H
H
H
C
C OH
Cis vs. Trans
• 1) In nature
• 2)
• 3)
Reasons for hydrogenation:
1) To change the physical properties of a
product:
2) To make a product with fat more stable:
Effects on Lipoprotein Levels (Lipid Profile)
SFA
MUFA
-3PUFA
-6PUFA
Trans
Triglycerides (triacylglycerols)
• TG =
• TG’s =
H
O
H
H
H
H
H
H
H
H
H
H
H
H
H 1C O
C
C
C
C
C
C
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
H
H C O
3
H C O
H
CH3
O
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
O
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
Triglyceride
H
H
H
CH3
CH3
Phospholipids (PL):
H
H 1C
H
C
O
O
O
H
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
H
O
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
O
3
H C
H
O
CH3
O
P
O
-
H
H
C
C
H
H
N
+
H
CH3
CH 3
CH 3
Lecithin
CH 3
Sterols
H
Cholesterol
H3C
C
CH2
CH2
CH2
CH3
CH
CH3
H
H3C
C
CH2
CH2
CH2
HO
CH3
CH
CH3
O
H3 C-CH2 -CH2-CH2 -CH2-CH=CH -CH 2 -CH2-CH2 -CH2-C-O
Cholesterol ester
Sterols made from cholesterol:
• 1)
• 2)
• 3)
Types of Lipoproteins
• Function =
• 1) Chylomicrons
• 2) Very Low density Lipoprotein (VLDL)
• 3) Low density Lipoprotein (LDL)
• 4) High density Lipoprotein (HDL)
Types of Lipoproteins
• 1. Chylomicron made by the small
intestines, is absorbed into the lymph vessel
then moves into the bld.
• Function is to:
a.
b.
Types of Lipoproteins
• 2. VLDL: after a meal the liver converts
excess carbohydrate and excess protein into
fat.
• The liver will then assemble all this fat,
including the fat from the chylomicron
remnants into VLDL (very low density
lipoprotein)
Continuing VLDL:
• VLDL is secreted into the blood stream.
• The function of VLDL:
• 1)
• • • -
Types of Lipoproteins
• 3. LDL: LDL arises from VLDL once it
has lost a lot of its TG.
• LDL function:
Types of Lipoproteins
• 4. HDL: HDL (high-density lipoprotein) is
secreted into blood.
• The function of HDL:
•
• Does “Reverse cholesterol transport”
CHD (coronary heart disease,
atherosclerosis)
• Atherosclerosis (AS): LDL circulating in the
blood stream contains fat (PUFA’s) that can
become oxidized, termed oxLDL. It is oxLDL
that is readily taken up and retained in the artery
wall. Specifically, macrophages (immune cells
residing in the artery wall) take up the oxidized
LDL. This results in a build up of LDL and other
material = AS plaque.
Oxidation
• Oxidation is the process that occurs
normally and in certain pathological
conditions in the body. It is not a rare event.
When compounds in the body get oxidized
they are damaged. DNA, proteins, PUFA’s
in cell membranes and LDL are all possible
targets of oxidant attack and damage.
Antioxidant Defense Systems
• 1. Prevent oxidation from being initiated
• 2. Halt oxidation once it has begun
• 3. To repair oxidative damage
Antioxidant Mechanisms:
• 1. Antioxidant vitamins (vitamins C, E,
carotenoids)
• 2. Other non-essential antioxidants chemicals in
foods (flavonoids, and other phytochemicals)
• 3. Antioxidant enzyme systems that are made by
the body and often require various minerals for
normal functioning (super oxide dismutase (SOD),
which requires Mn, Cu, Zn; glutathione
peroxidase (GPX), which requires Se; and
catalase).
Factors associated with LDL accumulation in artery wall
and oxidized LDL:
• Factors that aren’t dietary or are genetic:
– Being male
– Being post-menopausal female
– Family history of heart disease before the age
of 55 (some are associated with genetic defects
in LDL receptors)
Factors associated with LDL accumulation in artery
wall and oxidized LDL:
• Factors that are affected by diet:
– Elevated levels of LDL
• More LDL around to potentially oxidize and
accumulate in artery wall
– High blood pressure
• Damages the artery wall, allowing LDL to enter the
wall more readily
Continued Dietary Factors
• Factors that are affected by diet:
– Cigarette Smoking
• Damages the artery wall
• Cigarette smoke products are oxidants and can
oxidize
• Cigarette smoking compromises the body’s
antioxidant vitamin status, especially vit. C
– Low levels of HDL
• HDL carries cholesterol from artery walls back to
the liver
Continued Dietary Factors
• Factors that are affected by diet:
– Low levels of antioxidant vitamins E and C, ß-carotene
• E especially and C protect LDL from oxidation
– Low levels of other dietary antioxidants
• Phenolics, flavonoids, red wine, grape juice, vegetables, fruits
– Sedentary (exercise is the most potent factor to raise
HDL levels)
– Obesity promotes a lowered HDL, whereas attaining
ideal body weight promotes higher HDL
Elevated Homocysteine Levels:
• Homocysteine is normally produced in the body
during certain metabolic pathways and is normally
metabolized to other products. If homocysteine is
not properly metabolized the elevated levels of
homocysteine occur and this damages artery walls,
increasing the oxidation of LDL. Elevated
homocysteine levels are significantly correlated
with increased risk to heart disease. Vitamins B6,
B12, and folic acid greatly help to normalize
homocysteine levels and increase HDL
Dietary/Lifestyle Prevention/Intervention of Heart
Disease
Decrease LDL
Increase HDL
Increase
Antioxidants
 saturated fat
MUFA/ PUFA
MUFA/ PUFA
 cholesterol
 -3 oils (fish)
vegetables
 -3 oils (fish)
 exercise
fruits
 fiber
Stop smoking
Stop smoking
body weight, if
overweight
 fiber