chapter 5 lipids
What is cholesterol?
A waxy lipid found in all body cells. It has a structure containing multiple chemical rings that is found only in foods that contain animal products.
What is an emulsifier?
A compound that can suspend fat in water by isolating individual fat droplets, using a shell of water molecules or other substances to prevent the fat from coalescing.
what is eicosapentaenoic acid (EPA)
An omega-3 fatty acid with 20 carbons and 5 carbon-carbon double bonds. It is present in large amounts in fatty fish and is slowly synthesized in the body from alpha-linolenic acid.
what is a hemorrhagic stroke
Damage to part of the brain resulting from rupture of a blood vessel and subsequent bleeding within or over the internal surface of the brain.
What is a cerebrovascular accident?
Death of part of the brain tissue due typically to a blood clot. Also termed a stroke.
What is a myocaridal infarction?
Death of part of the heart muscle. Also termed a heart attack.
what is alpha-linolenic acid
An essential omega-3 fatty acid with 18 carbons and 3 double bonds.
what is linoleic acid
An essential omega-6 fatty acid with 18 carbons and 2 double bonds.
______ is a phospholipid that protects nerve cells.
Sphingomyelin
Which of these foods provides the most calories from fat? sugar, avocados, cheese and butter
butter
Lipids (mostly fats and oils) are composed primarily of the elements _________; they contain _____ oxygen atoms than do carbohydrates.
carbon and hydrogen fewer
______ contain many phosopholipids.
cell membranes
Lipoproteins are classified into four groups—______________________—based on their densities.
chylomicrons, VLDL, LDL, and HDL
Risk increases with low ______ because little cholesterol is transported back to the liver and excreted.
HDL
____ sends excess blood cholesterol to the liver.
HDL
risk factors for cardiovascular disease
High blood cholesterol Smoking Hypertension Diabetes Low HDL Advanced age Family history Obesity
A mix of ______ is burned for fuel during endurance exercise, but muscles rely mainly on ______ during short, intense exercise.
fat and carbohydrates carbohydrates
Various forms of phospholipids are found in body cells, and they participate in ____
fat digestion, absorption, and transport.
Triglycerides and other fats in food carry _______ to the small intestine and aid their absorption.
fat-soluble vitamins
A _____ is basically a long chain of carbons bonded together and flanked by hydrogens.
fatty acid
four types of lipids
fatty acid, triglyceride, phospholipid, and sterol
Triglycerides are composed of
fatty acids and glycerol
The products of fat digestion in the small intestine are
fatty acids and monoglycerides.
chylomicrons are composed of large droplets of lipid surrounded by a thin, water-soluble shell of phospholipids, cholesterol, and protein. The water-soluble shell around a chylomicron allows the lipid to
float freely in the water-based blood.
what is a trans fatty acid
A form of an unsaturated fatty acid, usually a monounsaturated one when found in food, in which the hydrogens on both carbons forming the double bond lie on opposite sides of that bond.
what is lecithin
A group of compounds that are major components of cell membranes. (phospholipid)
what is glycerol?
A three-carbon alcohol used to form triglycerides.
Fat replacement options include:
Replacing fat with water Replacing fat with lower-calorie starch derivatives Replacing fat with plant-based gum fiber to thicken the food Replacing fat with lower-calorie protein globules that feel like fat. These protein globules are created from milk or egg proteins.
Which of these foods is a good source of saturated fatty acids? Olive oil, Peanut oil, Beef fat, Corn oil
beef fat
The liver takes cholesterol from the bloodstream to form replacement ________
bile acids
Under the right circumstances, digestion is rapid and thorough. The "right" circumstances include the presence of
bile from the gallbladder.
Emulsification improves digestion and absorption because as large fat globules are __________, the total surface area for lipase action ____
broken down into smaller ones increases
Cholesterol-based deposits in the arteries can reduce or cut off blood flow, causing
cardiovascular disease (heart attacks and strokes).
The cholesterol and protein components of LDL provide some of the building blocks necessary for _________, such as synthesis of cell membranes and hormones.
cell growth and development
The _____ content of the heart, liver, kidney, and brain is high, reflecting its critical role in these organs.
cholesterol
Unsaturated fatty acids, with their double bonds, can exist in two different structural forms, the
cis and trans forms.
some trans fatty acids, known as _______, occur naturally.
conjugated linoleic acid (CLA)
Which of these foods is a good source of polyunsaturated fatty acids? Olive oil, Peanut oil, Beef fat, Corn oil
corn oil
The typical forms of cardiovascular disease—________________—are associated with inadequate blood circulation in the heart and brain related to buildup of this plaque.
coronary heart disease and strokes
Acids present in the bile act as _______ on the digestive products of lipase action, by doing what?
emulsifiers and suspending the monoglycerides and fatty acids in the watery digestive juices.
These triglycerides, and the fatty acids that they are made of, serve four main roles in the body:
energy, energy storage, vitamin absorption and protection for the body
The raw materials for lipid and cholesterol synthesis include _____ taken up from the bloodstream, as well as _________ derived from carbohydrates, protein, and alcohol
free fatty acids and carbon and hydrogen
Phospholipids are found in body cells, and they participate in fat digestion in the
intestine
The body's main emulsifiers are the ________, produced by the liver and released into the small intestine via the gallbladder during ____
lecithins and bile acids digestion
Cardiovascular disease begins when the _________ of a blood vessel is damaged.
lining
In the first phase of fat digestion, the stomach (and salivary glands to some extent) secretes the enzyme
lipase
The enzyme ____ in the saliva begins to digest fats when you eat them.
lipase
______ are energy-dense: fatty acids from triglycerides contain more than twice the calories per gram (on average, 9 kcal) as proteins and carbohydrates (on average, 4 kcal each).
lipids
The liver also is the manufacturing site for
lipids and cholesterol.
Most lipids are transported in the blood as part of a structure called a(n) _______________.
lipoprotein
Once a chylomicron enters the bloodstream, the triglycerides in its core are broken down into fatty acids and glycerol by an enzyme called ________, attached to the inside walls of the blood vessels
lipoprotein lipase
_________ carry insoluble fats through the lymph system and bloodstream.
lipoproteins
Several medications to control blood cholesterol trigger the _________ to reduce cholesterol.
liver
The ________ produce most of the HDL in the blood.
liver and intestine
Because lipids are generally large and not water-soluble, your _____ picks most of them up after digestion and special carriers called ____ help distribute lipids throughout the bloodstream.
lymph system and lipoproteins
After chylomicrons leave the intestinal cells, they are transported via what system?
lymphatic
In the small intestine, triglycerides are broken down by lipase into smaller products, namely _____
monoglycerides (glycerol backbones with a single fatty acid attached) and fatty acids.
Olive and canola oils contain a high percentage of ____________ fatty acids.
monosaturated
the general consensus among nutrition experts suggests that limitation of saturated and trans fat intake should be the primary focus and that the diet needs to contain a balance of
omega-3 and omega-6 fatty acids
These _______ and ________ form parts of vital body structures, perform important roles in immune system function and vision, help form cell membranes, and produce eicosanoids, which are involved in practically all important functions in the body.
omega-6 and omega-3 fatty acids
Products marketed as "fat free" must have less than _____ of fat per serving.
one-half of a gram
Women who smoke and take _________ have a much higher risk of cardiovascular disease.
oral contraceptives
Which of these foods is a good source for phospholipids? Sauerkraut Whole milk Mayonnaise Organ meats
organ meats
The two most common surgical treatments for coronary artery blockage are ____
percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass graft (CABG).
A combination of _________ and a blood clot can cut off blood circulation in an artery.
plaque
As the duration of exercise increases, the percent of fatty acids used for exercise ____ as the percent of carbohydrates ____. Other body tissues also use fatty acids for energy need
rises and falls
Which of the following would be the richest source of polyunsaturated fatty acids? a. Beef b. Chicken c. Olive oil d. Safflower oil
safflower oil
_____ is a good food source for omega-3 fatty acids.
salmon
Because ________ are straight and can be packed together closely, they are solid at room temperature.
saturated fatty acids
a fat or an oil is classified as __________ based on the type of fatty acids present in the greatest concentration
saturated, monounsaturated, or polyunsaturated
If LDL is not readily cleared from the bloodstream, ______ in the arteries take up the lipoprotein, leading to a buildup of ____ in the blood vessels
scavenger cells and cholesterol
_____ keep the liver from producing too much cholesterol
statins
The main problem with the fat replacer olestra is that it can bind
the fat-soluble vitamins and reduce their absorption.
Each triglyceride molecule consists of ______ bonded to ___
three fatty acids and glycerol
More than 95% of heart attacks are caused by
total blockage of the coronary arteries due to a blood clot forming in an area of the artery already partially blocked by plaque.
The bacteria that live in the rumens of some animals (cows, sheep, and goats, for example) produce _______ from the polyunsaturated fats in the grass the animals are fed.
trans fatty acids
The process of hydrogenation produces
trans fatty acids
________ are mostly man-made.
trans fatty acids
If the fatty acid is a more typical long-chain variety, it must be reformed into a _____ in the _____ and eventually enter circulation via the lymphatic system.
triglyceride and intestinal absorptive cell
The body stores excess protein as
triglycerides
Each double bond twists the fatty acid so it cannot be packed closely with another fatty acid. This makes it liquid at room temperature. which lipid is this?
unsaturated fatty acid
______ are synthesized by the liver to transport fat to the rest of the body.
very low density lipoproteins
Reduced-fat foods sometimes replace fat with what substance?
water
If the chain length of a fatty acid is less than 12 carbon atoms, it is _____ and will therefore probably travel as such through the _____ that connects directly to the liver.
water soluble and portal vein
_____ are rich in triglycerides and thus are very low in density.
VLDLs
what is a vegan?
a person who does not eat or use animal products.
In their natural form, monounsaturated and polyunsaturated fatty acids usually are in the ____ form
Cis
The Acceptable Macronutrient Distribution Range is that total fat intake should be _____ of total calories
20% to 35%
lipids should comprise ______ of an adult's total calorie intake.
20% to 35%
A claim of "reduced fat" means the product has at least _____ fat than is usually found in that type of food
25% less
"low fat" indicates, in most cases, that a product contains no more than ____ of fat per serving.
3 grams
what is a phosholipid
Any of a class of fat-related substances that contain phosphorus, fatty acids, and a nitrogen-containing base. The phospholipids are an essential part of every cell.
lipids dissolve in water. T/F
FALSE
what is lipase?
Fat-digesting enzyme produced by the salivary glands, stomach, and pancreas.
what are solid fats?
Fats that are solid at room temperature, such as butter and margarine. Foods containing solid fats tend to be high in saturated fatty acids or trans fatty acids.
Cholesterol is an essential structural component of cells and the outer layer of the _______ that transport lipids in the blood.
lipoprotein particles
What is a cis fatty acid?
A form of an unsaturated fatty acid that has the hydrogens lying on the same side of the carbon-carbon double bond.
Cholesterol is found only in
animal products
what does oxidize mean
In the most basic sense, an electron has been lost or an oxygen has been gained by a chemical substance. This change typically alters the shape and/or function of the substance.
what are eicosanoids
A class of hormone compounds, including the prostaglandins, derived from polyunsaturated fatty acids such as arachidonic acid and involved in the cellular activity affecting practically all important functions in the body.
what is sterol
A compound containing a multi-ring (steroid) structure and a hydroxyl group (-OH). Cholesterol is a typical example.
what are lipoproteins
A compound found in the bloodstream containing a core of lipids with a shell composed of protein, phospholipid, and cholesterol.
what is a saturated fatty acid
A fatty acid containing no carbon-carbon double bonds.
what is a monounsaturated fatty acid
A fatty acid containing one carbon-carbon double bond.
what is a polyunsaturated fatty acid
A fatty acid containing two or more carbon-carbon double bonds.
Approximately __ of the bile acids are recycled. Only ____ ends up in the large intestine to be eliminated in the feces.
98% and 1% to 2%
What is a monoglyceride?
A breakdown product of a triglyceride consisting of one fatty acid attached to a glycerol backbone.
what is a long-chain fatty acid
A fatty acid that contains 12 or more carbons.
What is a diglyceride?
A breakdown product of a triglyceride consisting of two fatty acids bonded to a glycerol backbone.
What is atherosclerosis?
A buildup of fatty material (plaque) in the arteries, including those surrounding the heart.
what is 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.
To reduce risk for cardiovascular disease, the AHA recommends that no more than ____ of total calories come from saturated fat and no more than ___ from trans fat. These are the primary fatty acids that raise ____
7%, 1% and LDL
Adipose cells contain about ____ lipid and only ____ water and protein.
80% and 20%
what is a lipoprotein lipase
An enzyme attached to the cells that form the inner lining of blood vessels; it breaks down triglycerides into free fatty acids and glycerol.
What is docosahexaenoic acid (DHA)?
An omega-3 fatty acid with 22 carbons and 6 carbon-carbon double bonds. It is present in large amounts in fatty fish and is slowly synthesized in the body from alpha-linolenic acid. DHA is especially present in the retina and brain.
what is arachidonic acid
An omega-6 fatty acid made from linoleic acid with 20 carbon atoms and 4 carbon-carbon double bonds.
What is oleic acid?
An omega-9 fatty acid with 18 carbons and 1 double bond.
what is an omega-6 (ω-6) fatty acid
An unsaturated fatty acid with the first double bond on the sixth carbon from the methyl end (-CH3).
what is an omega-3 (ω-3) fatty acid
An unsaturated fatty acid with the first double bond on the third carbon from the methyl end (-CH3).
what is BHA, BHT
Butylated hydroxyanisole and butylated hydroxytoluene—two common synthetic antioxidants added to foods.
_____ involves the removal and use of a saphenous vein (a large vein in the leg) or use of a mammary artery. The relocated vein is sewn to the main heart vessel (aorta) and then used to bypass the blocked artery. The procedure can be performed on one or more blockages.
CABG
_____ are the largest lipoproteins and contain dietary fat and originate only from the intestinal cells.
Chylomicrons
what does rancid mean?
Containing products of decomposed fatty acids that have an unpleasant flavor and odor.
What are the essential fatty acids?
Fatty acids that must be supplied by the diet to maintain health. Currently, only linoleic acid and alpha-linolenic acid are classified as essential.
what is an antioxidant?
Generally a compound that stops the damaging effects of reactive substances seeking an electron (i.e., oxidizing agents). This prevents breakdown (oxidizing) of substances in foods or the body, particularly lipids.
High amounts of _____ slow the development of cardiovascular disease, so any cholesterol carried by _____ can be considered "good" cholesterol.
HDL
Diets low in saturated fat, trans fat, and cholesterol encourage the uptake of _____ by the liver, thereby removing _____ from the bloodstream and decreasing the ability of scavenger cells to form atherosclerotic plaques in the blood vessels.
LDL
High levels of oxidized _________ cholesterol can contribute to plaque buildup in arteries.
LDL
The primary function of ____ is to transport cholesterol to tissues.
LDL
diets high in saturated fat, trans fat, and cholesterol reduce the uptake of ____ by the liver, increasing cholesterol in the blood and the risk for cardiovascular disease.
LDL
The longer _____ cholesterol is in the bloodstream, the more likely it is to be _____ and cleared by scavenger cells, which "swallow" the cholesterol, become "foam cells," and embed in the artery wall
LDL and oxidized
what are foam cells
Lipid-loaded white blood cells that have surrounded large amounts of a fatty substance, usually cholesterol, on the blood vessel walls.
what are chylomicrons?
Lipoprotein made of dietary fats surrounded by a shell of cholesterol, phospholipids, and protein. Chylomicrons are formed in the absorptive cells of the small intes-tine after fat absorption and travel through the lymphatic system to the bloodstream.
______ serve as vehicles for transport of lipids from the small intestine and liver to the body tissues
Lipoproteins
______ involves the insertion of a balloon catheter into an artery. Once it is advanced to the area of the lesion, the balloon is expanded to crush the lesion. This method works best when only one vessel is blocked, and it may be held open with metal mesh, called a stent.
PTCA
______, including ______, are also classified as lipids, although their structures can be quite different from the structure of triglycerides.
Phospholipid and sterols cholesterol
what are 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.
what is hydrogenation
The addition of hydrogen to a carbon-carbon double bond, producing a single carbon-carbon bond with two hydrogens attached to each carbon.
What is menopause?
The cessation of the menstrual cycle in women, usually beginning at about 50 years of age.
what is total parenteral nutrition?
The intravenous feeding of all necessary nutrients, including the most basic forms of protein, carbohydrates, lipids, vitamins, minerals, and electrolytes.
what is a very-low-density lipoprotein (VLDL)
The lipoprotein created in the liver that carries cholesterol and lipids that have been taken up or newly synthesized by the liver.
what is a low-density lipoprotein (LDL)
The lipoprotein in the blood containing primarily cholesterol; elevated LDL is strongly linked to cardiovascular disease risk.
what is a high-density lipoprotein (HDL)
The lipoprotein in the blood that picks up cholesterol from dying cells and other sources and transfers it to the other lipoproteins in the bloodstream, as well as directly to the liver; low HDL increases the risk for cardiovascular disease.
What is a trigylceride?
The major form of lipid in the body and in food. It is composed of three fatty acids bonded to glycerol, an alcohol.
What is systolic blood pressure?
The pressure in the arterial blood vessels associated with the pumping of blood from the heart.
What is diastolic blood pressure?
The pressure in the arterial blood vessels when the heart is between beats.
___ are the most common type of lipid found in the body and in foods.
Triglycerides
Which of the following is true about trans fatty acids found in hydrogenated fats? a. When consumed, they can decrease blood clotting. b. When consumed, they can raise serum LDL cholesterol. c. When consumed, they can lower serum LDL cholesterol. d. When consumed, they have no effect on serum cholesterol.
When consumed, they can raise serum LDL cholesterol.
At one end of the molecule (the alpha end) is an _____. At the other end (the omega end) is a _______
acid group and methyl group
Triglycerides contained in the diet and stored in ______ provide the ____ that are the main fuel for muscles while at rest and during light activity.
adipose tissue and fatty acids
An essential omega-3 fatty acid with 18 carbons and 3 double bonds is called
alpha-linolenic acid.