lipids
substances that do not dissolve in water
triglyceride
the major type of lipid in food and in the body; consisting of 3 fatty acids attached to a glycerol molecule
fatty acid
a molecule made up of a chain of carbons linked to hydrogens, with an acid group at one end of the chain
phospholipid
a type of lipid whose structure includes a phosphorus atom
sterol
type of lipid with a structure composed of multiple chemical rings
saturated fatty acids
a fatty acid in which the carbon atoms are bonded to as many hydrogen atoms as possible; contains no carbon-carbon double bonds
monounsaturated fatty acids
contain 1 carbon-carbon double bond
unsaturated fatty acids
contains one or more carbon-carbon double bonds; either monounsaturated or polyunsaturated
polyunsaturated fatty acids
contain more than 1 carbon-carbon double bond
omega-6 fatty acid
when the first double bond occurs between the 6th and 7th carbon atoms; ex: corn oil, safflower oil, soybean oil, nuts
omega-3 fatty acid
if the first double bond occurs between the 3rd and 4th carbon atoms; ex: flaxseed, canola oil, nuts
essential fatty acid
a fatty acid that must be consumed in the diet because it cannot be made by the body or cannot be made in sufficient quantities to meet the body's needs
tropical oils
found in plants common in tropical climates, saturated; ex: palm oil, palm kernel oil, coconut oil
hydrogenation
a process whereby hydrogen atoms are added to the carbon-carbon double bonds of unsaturated fatty acids, making them more saturated
emulsifiers
substances that allow fat and water to mix
phosphate group
chemical group containing phosphorus
lipid bilayer
double-layered sheet; formed by phospholipids
lecithin
one of the best known phospholipids; used as an emulsifier in margarine, salad dressings, chocolate, frozen desserts, and baked goods to prevent oil from separating; major constituent of cell membranes in the body; used to synthesize the neurotransmitter acetylcholine which activates muscles and plays an important role in memory; natural sources are eggs and soybeans
cholesterol
sterol, produced by the liver and consumed in the diet, which is needed to build cell membranes and make hormones and other essential molecules
plant sterols
help form plant cell membranes; can help reduce cholesterol levels in the body
monoglyceride
glycerol molecule with one fatty acid attached
micelle
particle that is formed in the small intestine when the products of fat digestion are surrounded by bile; facilitates the absorption of lipids
lipoprotein
particle that transports lipids in the blood
chylomicron
lipoprotein that transports lipids from the mucosal cells of the small intestine and delivers triglycerides to other body cells
lipoprotein lipase
enzyme present on the surface of cells lining blood vessels; breaks down the triglycerides in chylomicrons into fatty acids and glycerol
LDL receptor
protein on the cell membrane LDL particles binds to to deliver cholesterol
LDL
low density lipoprotein; high % cholesterol; transports cholesterol to cells; "bad cholesterol
HDL
high density lipoprotein; high % protein; transports cholesterol to the liver so it can be eliminated from the body; "good cholesterol
VLDL
very low density lipoprotein; made in the liver; delivers triglycerides to body cells
adipose tissue
body fat that lies under teh skin and around internal organs
linoleic acid
omega-6; essential fatty acid
alpha-linolenic acid
omega-3; essential fatty acid
essential fatty acid deficiency
condition characterized by dry, scaly skin and poor growth that results when the diet does not supply sufficient amounts of linoleic acid and alpha-linolenic acid
eicosanoids
regulatory molecules that can be synthesized from omega-3 and omega-6 fatty acids
arachidonic acid
omega-6 fatty acid synthesized from linoleic acid; found in animal and vegetable fats
eicosapentaenoic acid (EPA) & docosahexaenoic acid (DHA)
omega-3 fatty acids synthesized from alpha-linolenic acid; found in fatty fish
cardiovascular disease
any disease that affects the heart and blood vessels
atherosclerosis
type of cardiovascular disease in which cholesterol is deposited in the artery walls, reducing their elasticity and eventually blocking the flow of blood
inflammation
process whereby the body responds to injury
atherosclerotic plaque
cholesterol-rich material that is deposited in the arteries of individuals with with atherosclerosis
oxidized LDL cholesterol
inside the artery wall, LDL is oxidized to form this
macrophages
fill up with oxidized LDL cholesterol in the artery wall and are transformed into foam cells
foam cells
formed by macrophages; deposit cholesterol when they burst
antioxidant
substance that decreases the adverse effects of reactive molecules
water
lipids do not readily dissolve in
triglyceride
most common form of lipid found in the body
triglycerides, sterols, and phospholipids
three types of lipids
triglycerides
fatty acids are found in
acid group methyl group
the alpha end of a fatty acid chain is a ______ and the omega end is a ________
hydrogen
fatty acids can be saturated or unsaturated with
animal
_______ fats are high in saturated fatty acids
natural trans fats
improve insulin levels in diabetics and decrease risk of heart disease, cancer, and obesity
industrial trans fats
make worse insulin levels in diabetics and increase risk of heart disease, cancer, and obesity
long-chain
almost all fatty acids in the body and in food are
alpha-linolenic acid
the main omega-3 fatty acid
linolenic acid
the main omega-6 fatty acid
eicosapentaenoic acid and docosahexaenoic acid
Important for the brain and nervous system
the diet
omega-3 and -6 fatty acids must be obtained through
synthesis in the body
Omega 9 fatty acids can be obtained through
5%
Percent of calories per day that should come from fatty acids
flaky and itchy skin, diarrhea, and infection
side effects of fatty acid efficiency include
DHA and EPA
Regular intake of _____ and ____ promote healthy brain and heart activity
cell mebranes
Phospholipids are an important part of
lecithin
used as an emulsifier
animal food
Cholesterol is found only in
saturated and trans fats
types of fat that can more readily resist rancidity
partially-hydrogenated plant oils
To increase shelf-life, manufacturers add
Vitamin E
Antioxidant that helps protect food against rancidity by guarding against fat breakdown
BHA BHT Vitamin C
synthetic antioxidants added to foods polyunsaturated fats to prevent rancidity
small intestine
In the ______ lipase breaks down triglycerides into smaller units, namely momglycerides
98%
_____ percent of bile acids are recylced
emulsifier
during digestion, bile from the gallbladder acts as an
Liver
after fat digestions, the bile is reabsorbed and ends up back in the
Monpause
the cessation of the menstrual cycle, usually beginning at about 50 years of age
scavenger cells
specific form of white blood cells that can bury themselves in the artery wall and accumulate LDL. As these cells take up LDL, they contribute to the development of atherosclerosis.
atherosclerosis
a buildup of fatty material (plaque) in the arteries, including those surrounding the heart
triglycerides
we store energy mainly in the form of
Cholesterol
building block of bile acids
20-30%
According to the 2010 Dietary Guidelines for Americans and the Acceptable Macronutrient Distribution Range is that total fat intake should be ________ of total calories
7% 1%
To reduce risk for heart disease, the American Heart Association suggests that no more than ____ of calories come from saturated fat and no more than ______ from trans fat
trans and saturated fats
Primary acids that raise LDL
33% 13%
The average American consumes _____ of their calories from saturated fat and _______ from trans fat
fish oil supplements
can be employed to treat elevated blood triglycerides
plaque
a cholesterol-rich substance deposited in the blood vessels; it contains various white blood cells, smooth muscle cells, various proteins, cholesterol and other lipids, and eventually calcium
myocardial infarction
death of part of the heart muscle. Also termed heart attack
cerebrovascular accident (CVA)
Death of part of the brain tissue due typically to a blood clot. Also termed stroke
Cardiovascular disease (heart attack and stroke)
associated with inadequate blood circulation in the heart and brain related to buildup of plaque
systolic blood pressure
the pressure in the arterial blood vessels associated with the pumping of blood from the heart
diastolic blood pressure
the pressure in the arterial blood vessels when the heart is between beats.
high cholesterol, smoking, hypertension, diabetes
Risk factors for cardiovascular disease include
b
Margarine is usually made by a process called______, in which hydrogen atoms are added to carbon-carbon double bonds in the polyunsaturated fatty acids found in vegetable oils.
a.saturation
b. esterification
c. isomerization
d. hydrogenation
a
Essential fatty acids that cause a decrease in blood clotting are
a. omega-3
b. omega-6
c. omega-9
d. prostacycins
c
Cholesterol is
a. a dietary essential; the human body cannot synthesize it
b. found in foods of plant origin
c. an important part of human cell membranes and necessary to make some hormones
d. all of the above
b
Which of the following groups of foods would be important sources of saturated fatty acids?
a. olive oil, peanut oil, canola oil
b. palm oil, palm kernel oil, coconut oil
c. safflower oil, corn oil, soybean oil
d. all of the above
a
Lipoproteins are important for
a. transport of fats in the blood and lymphatic system
b. synthesis of triglycerides
c. synthesis of adipose tissue
d. enzyme production
a
Which of the following foods is the best source of omega-3 fatty acids?
a. fatty fish
b. peanut butter and jelly sandwich
c. lard and shortenings
d. beef and other red meats
c
Immediately after a meal, newly digested and absorbed dietary fats appear in the lymph and then the blood as a part of which of the following?
a. LDL
b. HDL
c. chylomicrons
d. cholesterol
c
High blood concentrations of ______ decrease the risk of cardiovascular disease
a. low-density lipoproteins
b. chylomicrons
c. high-density lipoproteins
d. cholesterol
b
phospholipids such as lecithin are used extensively in food preparation because they
a. provide agreeable feel of fat melting on the tongue
b. are excellent emulsifiers
c. provide important textural features
d. impart delicate flavors
c
The main form of lipid found in the food we eat is
a. cholesterol
b. phospholipids
c. triglycerides
d. plant sterols