-
lipids include: ?, ?, ?
- Triglycerides,
- Phospholipids, and Sterols
-
fats and oils?
triglycerides
-
they are ? in water
insoluble
-
how do fatty acids varry?
- length of carbon chain
- degrees of unsaturation
- # of double bonds
-
what is saturation?
- affects physical
- characteristics of fat and its storage properties
-
Trans-fatty acids
- have same negative health
- effects as saturated fatty acids
-
Long-chain fatty acids are
found primarily in
meat, fish, and vegetable oils
-
Medium- and short-chain fatty acids are
found in
dairy products
-
Saturated fatty acids
carry ?
- maximum possible number of
- hydrogen atoms
-
Called a saturated fat:
when
- most of the fatty acids
- are saturated
-
Triglycerides are lipids with
- 3 fatty acids attached to
- a glycerol
-
Degree of Unsaturation
Firmness
-
Saturated fats
solid at room temperature
-
Polyunsaturated fats
- liquid at
- room temperature
-
Shorter fatty acid chains
are ?
- softer at room temperature
- than longer chains
-
Saturated
- (animal fat & tropical
- oils)
- §Coconut oil, palm oil, butter, beef tallow,
- lard
-
Monounsaturated
§Olive, canola and peanut oils
-
Polyunsaturated
§(vegetable oils)
- §Safflower, flaxseed, walnut, sunflower, corn,
- soybean and cottonseed oils
-
Degree of Unsaturation
Stability
-
Saturated fat is more resistant to
spoilage
-
Monounsaturated fat is
slightly less resistant to
spoilage
-
Polyunsaturated fat
spoils most quickly
-
•Protection
from rancidity
- –Seal
- in airtight containers away from light
- –Hydrogenation
- (stiff at room temp)
-
Unsaturation
Hydrogenation
- •Protects
- against oxidation - prolongs shelf life
-
§Trans-Fatty Acids :-(
- •Change
- from cis to trans configuration; act like saturated fats in
- body
-
Heart disease connection with
trans fats
-
Conjugated linoleic acid
is a naturally occurring
- trans fat that may be
- beneficial to health
-
Phospholipids in Foods contain
- glycerol, two fatty acids
- and a phosphate group with a molecule of choline
-
Phospholipids are used as ?
emulsifiers in foods such as manoyase
-
Phospholipids enable
- lipid transport across
- cell membranes
-
Lechithin
- •made
- by liver; supplements increase energy intake and can cause GI distress
-
Food
sources lecithin:
- eggs, liver, soybeans,
- wheat germ and peanuts
-
Cholesterol best known
sterol
-
Sterols are found in
plant and animal foods
-
Exogenous cholesterol
found in
- animal foods only - meat, eggs, fish, poultry and dairy
- products
-
Fat
soluble vitamin D synthesized from
cholesterol
-
sterols are the starting material for
- bile acids, sex hormones,
- adrenal hormones & vitamin D
-
sterols are the structural components of
cell membranes
-
liver produces
cholesterol
-
Atherosclerosis
- disease that causes heart
- attacks; occurs when cholesterol forms deposits in artery walls
-
Hydrophobic nature of
lipids
-
Lipids separate from
watery fluids of digestion
-
Digestive enzymes are hydrophilic
water loving
-
Bile from liver emulsifies
lipids
-
Enzymes then break down
lipids to
monoglycerides and fatty acids
-
fat digestion in gi tract
- mouth and salivary glands
- stomach
- small intestine
- large intestine
-
Lipid Digestion in the mouth
salivary glands release lingual lipase
-
lipid digestion in stomach?
- muscle contractions...
- disperse fat into smaller droplets; fat exposed to gastric lipase enzyme
-
Cholecystokinin (CCK)
- signals gallbladder to
- release bile
-
Pancreatic and intestinal
enzymes hydrolyze (break down
lipids to monoglycerides and fatty acids
-
Phospholipids
are hydrolyzed
-
Sterols are absorbed
as they are
-
Bile’s Routes
Enterohepatic circulation
reabsorbed and recycled
-
Soluble fibers
- (oats, beans, vegetables
- & fruit) trap bile acids and excrete from body through large intestine
-
In
the liver, bile is
made from
cholesterol
-
In
the gallbladder
bile is stored
-
In
the small intestine,
bile emulsifies fat
-
In
the colon, bile that has been trapped by soluble fibers is
los as feces
-
Glycerol and short- and
medium-chain fatty acids diffuse and are absorbed
directly in blood stream
-
Monoglycerides and long-chain fatty acids form
- micelles;
- absorbed and reformed into new triglycerides
-
Lipoprotein
carriers
“vehicles”
-
§Chylomicrons
- Largest of lipoproteins . beach ball
- •Least dense
-
VLDL
- §Very-Low-Density
- Lipoproteins)
•Composed 2/3 as triglyceride
•Think softball size
•Made by liver & intestines
•Transport lipids to tissues
-
LDL
- think golf ball size
- •Transports cholesterol to body
- cells
-
HDL
- §High-Density
- Lipoproteins) :-)
- •Made of over 50% protein (only
- 5% TG, 20% cholesterol)
- •Think steel ball-bearing 3/4”
- diameter
- •Transport cholesterol from cells
- to liver
- •Protects against atherosclerosis;
- reduces risk heart disease (“good cholesterol”)
-
Hypercholesterolemia
high total cholesterol
-
Hypertriglyceridemia
high TG
-
Hyperlipidemia
- high TG, high cholesterol
- or both
-
Dyslipidemia
- abnormal lipid levels,
- usually too high
-
Genes
- influence lipoprotein
- activity
-
Eat fish
- ameircan heart association recommendation
- Good protein; low in saturated fat
- omega 3 ***
-
Other sources omega-3s
- vegetable oils (canola,
- soybean and flaxseed), walnuts, flaxseeds
-
roles of tryg;ycerides (fats)
- §Use
- carbohydrate and protein efficiently (nutrients support each other)
§Insulation
- §Shock
- protection - cushion bones & vital body organs
-
Essential Fatty Acids
cannot be made by the body
-
why does the body not store all xtra energy as glycogen?
- fat holds 6x more energy than fat
- you would weigh more
-
Fasting metabolizes
- fat, but fat requires
- carbohydrate and protein for complete breakdown
-
Ketone bodies
- can be made from fat
- fragments
-
High intakes of saturated fat and trans fat and high blood LDL
cholesterol
increased risk of heart disease
-
Cholesterol accumulates in
- arteries, restricts blood
- flow and raises blood pressure
-
Food sources of
cholesterol
- egg yolks, milk products,
- meat, poultry and shellfish
-
Too little fat can be
detrimental to health
-
fat guidelines
- lean cuts of meant/ meat alternatives
- fat free and low fat milk products
- wide variety vegetables,
- fruits, and whole grains
-
fat replacers are ingredients
- derived from carbohydrate,
- protein or fat
-
fat replacers decreace
- absorption of fat-soluble
- vitamins and may cause GI distress in some
-
Saturated fat and trans fat are poor
heart health
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