chapter 5; the lipids Flashcards
the primary source of the body’s energy reserves, stored in [..] tissue as triglycerides.
- adipose tissue is connective tissue composed primarily of adipocytes (fat cells), [..], [..], and [..] the body’s organs (such as kidneys, heart, and other organs)
adipose,
cushions, protect, and insulates + storage site for fat soluble vitamins
dietary fat and lipids provide [..] calories per gram
9
(significantly more dense than carbs and proteins)
dietary fat and lipids are are required for absorption and transportation of fat-soluble vitamins; vitamins [..], [..], [..]. and [..] as well as [..]
A, D, E, and K
phytochemials
dietary fat and lipids are component of cell membranes and are required for making hormones that regulate numerous body functions
yes
found in plant and animal foods, [..] fat, or what we commonly call fat, is an essential component of a healthy diet
dietary
when selected and consumed in appropriate proportions, can fat confer some important health benefits
yes as some fats are essential nutrients
fat consumption contributes to satiety (the sensation of feeling [..]) in part by slowing gastric [..], which keeps [..] in the stomach a little longer
full, emptying, food
dietary fats can cause foods to be digested and absorbed over longer periods, which can improve blood [..] control following the ingestion of high-[..] foods when fats are included
glucose
carbohydrate
inadequate stores of fat can reduce [..] in both men and women
fertility
many popular foods get most of their calories from [..], and with their taste appeal and caloric density, it can be easy for some of us to eat to much.
fat
fats are a subclass of [..], a group of compounds made up of carbon, hydrogen, and a small amount of oxygen that generally can’t mix or dissolve in water (they are water insoluble)
lipids
water
in the cell membranes, lipids give those structures [..] and [..], and various lipids are required for the synthesis of some [..] and hormone like substances
flexibility, integrity
hormones
the four most common lipid classes are fatty acids, triglycerides, sterols, and phospholipids (such as lecithin)
fatty acids - a major energy source
triglycerides - the most abundant lipid in our diet and storage form of fat in our bodies
sterols - cholesterol is the primary dietary sterol
phospholipids - the primary lipid in cell membranes
[..] acids are a type of lipid with multiple functions
fatty
fatty acids are metabolized to provide energy, they regulate rates of gene [..], and they are the [..] material used to synthesize several hormone like compounds in the body
energy, expression, starting
fatty acids are also the primary components of two other types of lipids, [..] and [..]
triglycerides and phospholipids
short chain fatty acids have fewer than [..] carbons; medium chain fatty acids have [..]-[..] carbons, and long chain fatty acids have more than [..] carbons
6
6-12
12
saturated fatty acids, with carbon atoms having every available bond filled with hydrogen atoms, are relatively [..] at room temperature
solid
saturated fatty acids, are typically highest (as a percentage of total fat) in [human or animal] products (such as meats and dairy), but they are also abundant in some [fruit or vegetable] oils (such as coconut oil, palm kernel oil, palm oil, and cocoa butter)
animal
vegetable
the rest of the fatty acids are [..], with less hydrogen and one or more double bonds (or point of unsaturation) between carbon atoms
unsaturated
unsaturated fats are generally [..] at room temperature
liquid
unsaturated fats are found most abundantly in [..] foods, such as seeds, nuts, grains, and most vegetable oils
plant
fatty acids with one point of unsaturation are called [..] fatty acids (abundant in olive and canola oils and nuts)
monounsaturated fatty acids
those with more than one point of unsaturation are called [..] fatty acids (abundant in corn, safflower, sunflower, sesame, and soybean oils).
polyunsaturated
Morris concluded that a diet high in saturated and trans fats may accelerate cognitive [incline or decline] and [increase or decrease] the risk of AD and that a diet rich in monounsaturated and polyunsaturated fat appears to exert protective effects on the brain associated with a reduced risk of AD
decline
increase
higher saturated fat intake is linked with greater cognitive decline
yes
triglycerides are the most abundant type of dietary lipid, providing a large portion of total food calories, and they are required for the efficient transport of certain fat-soluble vitamins (A, D, E, and K) through the Body
yes
a triglyceride is made up of three fatty acid chains bound to one [..], a small three cabon molecule that makes up the glycerol backbone of each triglyceride
glycerol
all triglycerides are composed of a mix of short-chain, medium-chain, and long chain fatty acids. they seldom contain exclusively one type of fatty acid
yes
because triglycerides consist of [..] fatty acids, they can provide [..] fatty acids, the fatty acids our bodies need but cannot synthesize in [..] amount
three, essential, sufficient
essential fatty acids must be obtained through our [..]
diet
chemically, sterols are complex [..] of four interconnected carbon rings with a hydrocarbon side chain
lipids
the most discussed sterol is [..]. a molecule with varied functions, cholesterol is a critical component of our cell [..] and is needed as a precursor (a compound that is used to synthesize another compound) for the synthesis of bile acids, vitamin D, and steroid hormones (such as estrogen and testosterone), but it does not provide any energy
cholesterol
membrane
cholesterol is synthesized in nearly tissue in the body but in particularly large quantities by the [..]
liver
approximately [..]% of the cholesterol in blood is made in our body, which provides all the cholesterol needed for body [..]
75%
functions
although a dietary source of cholesterol is not required, we consume cholesterol in animal foods such as [..] and [..] products
meats
dairy
plants synthesize other types of sterols (and the closely related stanols), but these types are poorly [..] by the body and can actually interfere with and lower [..] absorption
absorbed
cholesterol
some spreads and other food products are fortified with plant sterols or stanols to help lower [..] levels in the body
cholesterol
as with heart disease, growing evidence links high levels of cholesterol in the blood to the development of [..] and other forms of [..]
AD, dementia
those with higher levels of total cholesterol had an increased risk of developing dementia later in life compared to those with normal or low blood cholesterol levels
yes
a diet high in saturated fat and cholesterol has been shown to cause brain [..] and lesions and [..] memory. increased cholesterol accelerates the buildup of sticky protein called [..] beta, a characteristic of AD. amyloid beta can assemble into cell pores or channels to accumulate into clumps in those cells, which travel to the [..] and disrupt its function
inflammation
impair
amyloid
brain
phospholipids, as their name implies, are [..]. are a primary component of cell [..] and are required for the [..] of other lipids in the blood
lipids , membranes
transport
because the body can produce phospholipids, they are not considered an essential nutrient
yes
most phospholipids are similar to triglycerides in structure in that they have a glycerol backbone, but they differ in that they have [..] rather than [..] attached fatty acids. attached to the third position is a phosphate group and one of several water soluble “head groups”
two, three
functioning as a semipermeable barrier to the external cell environment, the lipid bilayer controls the molecules that enter and exit the [..] cell. they also play a central role in transporting [..] throughout the body. despite their importance, they are not essential nutrients as we are able to [..] all that we need
internal
lipids, synthesize
hydrogenation in trans fatty acids are a chemical process by adding hydrogen molecules to an unsaturated fat to make it [..] and [..] at room temperature (changes the chemical configuration but makes fats more [..])
saturated, solid
stable
trans fatty acids found in “partially hydrogenated” vegetables, created by adding hydrogen molecules to [..] vegetable oil, known as “hydrogenation”
liquid
the two sided structural arrangement of phospholipids- one end water soluble and the other fat soluble- allows phospholipids to suspend fat in [..]. the fat soluble tails of phospholipids will surround small fat droplets, leaving the water soluble head of the phospholipid facing outward toward
water
an example of a phospholipid is lecithin. in addition to being the most [..] phospholipid in our body, lecithin is also frequently added to food products, such as salad dressing, as an emulsifier because of its ability to keep water and lipids from [..]
abundant
separating
blood lipids can also affect risk of AD, and a complete cholesterol test - also called a lipid panel - determines the amount of lipids circulating blood.
yes
as morris explained, a diet high in [saturated or unsaturated] fat and low in [saturated or unsaturated] fats increases the total blood cholesterol, which can be harmful to our health, increasing the risk of not only [..] but also [..] disease
saturated , unsaturated
dementia, heart
because lipids are not water soluble, and therefore cannot mix with water, the fat tends to clump together in the small intestines watery environment. the body’s solution to that problem is [..]
emulsification
emulsification aids digestion by breaking up large fat globules into much smaller droplets so that fat digesting enzymes can operate efficiently. [..] acids produced in the liver from cholesterol (and stored in the [..]) make emulsification possible. the molecular makeup of bile acids features a water soluble and fat soluble “face”. these two face molecules surround a small lipid droplets so that the lipids remain suspended in water instead of [..] together
bile , gallbladder
clumping
lipases , produced by the [..] and released into the [..] intestine, can now readily access the triglycerides suspended in these droplets and digest them into monoglycerides and free fatty acids.
pancreas
small
because most lipids are not soluble in water, they cannot dissolve in the watery environment of the bloodstream and require carriers for [..] in it
soluble
transport
lipoproteins are protein containing spherical particles that act as the primary carrier of [..] in blood
lipids
in the mucosal cells of the small intestine, triglycerides, other lipids, and hydrophobic substances of dietary origin are incorporated into a type of lipoprotein called a chylomicron. are too [..] to enter blood immediately after their formation, so they first enter the [..] system, which then delivers them into the blood stream
large
lymphatic
lipoproteins; chylomicrons (the largest and least dense particles) and very low-density lipoproteins (VLDL) are similar in that they both transport primarily triglycerides to adipose tissue and cardiac and skeletal muscles
yes
chylomicron; transport dietary fats and cholesterol from [..] to muscle and adipose tissue
intestines
LDL is converted to LDL. which primarily carries [..] to all cells in the body
cholesterol
VLDL carries mainly triglyceride from [..] to muscle and adipose tissue
liver
HDL picks up [..] from the body cells and returns them to the liver
cholesterol
high density lipoproteins (HDLs) often are referred to as “[..]” cholesterol. rather than delivering cholesterol, HDLs pick up as much [..] cholesterol as they can from cells throughout the body and take it back to the liver, which then uses the cholesterol to make [..] acids, excretes it directly into bile, or recycles it
good
excess
bile
high levels of HDL cholesterol are typically associated with a [higher or lower] risk for heart disease
lower
when the LDL cholesterol level rises too high and the HDL cholesterol level drops too low, it is this ratio - meaning the amount of each relative to each other - of lipoproteins (HDL to LDL) that is “bad” because high LDL cholesterol increases the risk of cardiovascular disease
yes
the human body needs fatty acids. most are easily supplied in sufficient amounts through our diet, and if not, we can make them from excess [..] and [..].
carbohydrates
proteins
two fatty acids are considered essential fatty acids because they cannot be synthesized by humans and must be supplied through the diet. these are [..]-linolenic acid (commonly called linolenic acid, for short) and linoleic acid
alpha
linoleic
linolenic acid is an omega-[..] fatty acid - with the first double bond of the carbon chain located in the third position
3
linolenic acid is an omega [..] fatty acid - with the first double bond of the carbon chain located in the third position
3
good sources of linolenci acid are walnuts, flax seeds, soy, canola oil, and chia seeds
in relation to linoleic acid, intake of linolenic is [high or low] in the diets of most Americans, who consume only about one tenth of essential fatty acids in the omega-3 form
low
linoleic acid is an example of an omega-[..] fatty acid, so called because the first double bond of the carbon chain is placed in the sixth position, counting from the omega end of the fatty acid. it is needed for normal growth and for synthesis of important hormone like compounds called eicosanoids
6
growth, eicosanoids
by far, linoleic acid is the most abundant [..] fatty acid in our diet. the primary sources are cooking oils, salad dressings, nuts, and seeds
polyunsaturated
trans fatty acids contain a [..] bond where hydrogen atoms are on [..] sides of the double bonds
double
opposite
trans - more than one (gender)
opposite (want to be opposite gender)
saturated fatty acids contain no [..] bonds; generally [..] at room temperature
double
solid
sat - two butt cheeks
solid - butt is solid
polyunsaturated fatty acids contain more than one [..] bond; [..] at room temperature
double
liquid
poly - more than one
poly - liquid from both genders
monounsaturated fatty acids contain [..] double bond; [..] at room temperature
one
liquid
mono - one
mono - liquid
Saturated fatty acids tend to be predominant in [..] fats, such as butter and ground beef, and in tropical oils, such as coconut oil. Unlike most saturated fatty acids, tropical oils are liquid at room temperature. Monounsaturated fatty acids are predominant in olive oil, avocados, and many types of nuts including almonds. Polyunsaturated fatty acids are predominant in corn, safflower, and soybean oils, as well as walnuts.
animal
Saturated fats are most abundant in animal fats and tropical oils. Butter, whole milk and cheese, hamburgers and pizza, bacon and sausage, and coconut oil are high in saturated fat. Plant-based fats tend to be lower in saturated fat and fat free dairy products contain no saturated fat.
important functions of dietary fats (triglycerides) is that they increase the palatability of foods, provide a feeling of fullness, and provide essential fatty acids
yes
many people who eat a western diet - such as North Americans and many Europeans - consume plenty of [..], just not necessarily the right kinds
fat
until recently, too much of the fat we consumed had undergone a process of hydrogenation, which makes unsaturated fats more [..] and [..] by chemically adding [..] to each carbon atom , flanking a double bond on the fatty acid chain to make them more saturated. this renders them [..] at room temperature and more resistant to becoming rancid (oxidation and/or decomposition that can occur in unsaturated fats, resulting in unpleasant taste and smell)
solid and stable
hydrogen
harder
one outcome of partial hydrogenation, however, is that the structure of some of the unsaturated fatty acids is converted from from their natural cis configuration to another configuration known as [..]
trans
these trans fatty acids raise levels of LDL cholesterol and lower levels of HDL cholesterol in blood, thereby increasing the risk of heart disease more than any other type of fat
as little as [..]% of total calories from trans fat can increase the risk of heart disease, stroke, or sudden death from these conditions and there causes
1%
given the risks of trans fats, the US food and drug administration [..] added trans fats (partial hydrogenated oils) from foods except in special circumstances. this ban went into effect on June 18, 2018, with Canada banning its use on September 15, 2018
banned
although a small amount of trans fat is [..] present in dairy products and beef, most of the trans fat we consumed prior to the ban had come from the partially hydrogenated oils used to extend the shelf life of processed foods or to increase the melting point of vegetable oils
naturally
since the early 1980s, in response to health messages and consumer demand, the marketplace has [..] and [..] reduced fat foods, including commercially formulated version of typically higher fat products, which have smaller percentage of calories from fat (and often saturated fat)
produced
promoted
the total amount of fat that Americans consume has not [increased or decreased] because we simply eat more food (and calories) than we did before
decreased
today, approximately one-[..] of the calories that American men and women consume come from fat.
third
surveys suggest that we are eating less fat from some sources, such as [..] and [..] (opting for low fat milk, for instance), but getting more fat in our diets from other sources, such as high fat [..] foods and [..] foods
meat and dairy
snacks
baked
within our overall fat intake, it is recommended that we emphasize unsaturated fats over saturated fats when choosing foods and added fats
to promote health and reduce the risk of chronic disease, the acceptable macronutrient distribution range (AMDR) for total fat has been set eat [..]-[..]% of our total calories
20-35%
LDL is bad cholesterol
HDL is good cholesterol
yes
monounsaturated fatty acid sources are [..] and [..] based fats
plant x2
e..g olives, olive oil, avocados, avocado oil, some nuts, such as peanuts and almonds
polyunsaturated fatty acid sources are most [..] and [..] oils
vegetable, seed
e..g corn, safflower, sunflower, sesame and soybean oils
fully hydrogenated oils do not produce trans fats but are still saturated fats and should be limited
yes
trans fats formed when foods are commercially friend in [..] hydrogenated oils (restaurant food, fast food)
partially
linolenic acid: omega 3 fatty acid is required for [..] component of cell membranes, and synthesis of omega-[..] eicosanoids
structural
3
EPA (eicosapentaenoic acid) and DHA (docosagexaenoic acid) are a long chain, omega-3 fatty acids made from linolenic acid, are protective against heart disease: reduces blood clotting, inflammation, blood pressure, reduces risk of dementia and alzeihmers, and is important for brain development in fetus, infants
best sources of linolenic acid: omega-3 fatty acid best sources are [..] oils (cold water fish) due to their DHA and EPA content . also found in flaxseed oil, walnuts, canola oil, soybeans, chia seeds
yes
most Americans don’t consume enough omega-3 compared to linoleic acid (omega-6) add a fish meal 1-2x/wk or eat plant sources frequently
yes
plant sterols are poorly [..] by humans and blocks [..] absorption, may help lower blood cholesterol. is found in fruits, veg, whole grains, nuts, seeds and sterol - fortified foods
absorbed
cholesterol
true or false; the body does not synthesize enough cholesterol on its own, so humans must obtain cholesterol from food
false
lipid digestion; small amount occurs in the mouth and stomach via lipases. most lipid digestion occurs in small intestine. facilitated by: bile acids (produced in the liver form cholesterol stored in gallbladder. it emulsifies lipids, aids digestion by breaking up fat globules, forming stable “mixture” in the gastrointestinal tract. pancreatic lipase where enzymes are released from pancreas that breakdown fats by removing fatty acids form the glycerol backbone of triglycerides
in order for lipid digestion and absorption to take place, what must be involved
lipases
and
bile acids
VLDLs; carry triglycerides from liver to muscle, cardiac tissue (to be used for [..]) and adipose tissue (for [..])
energy
storage
LDLs are smaller and denser, carry [more or less] cholesterol to body tissues
more
which lipoproteins carries cholesterol back to the liver for usage or proper disposal ?
HDL
high density lipoprotein
Lipases are secreted in the mouth and stomach, but little digestion occurs there. When fat moves from the stomach to the small intestine, bile (made in the liver and stored in the gallbladder) is released into the small intestine. The bile emulsifies the fat globules, breaking them into smaller droplets. Pancreatic lipase is secreted into the small intestine and readily digests triglycerides into monoglycerides and free fatty acids. The monoglycerides, free fatty acids, and other fat-soluble substances form micelles. The micelles move to the mucosal cells lining the small intestine where their contents are absorbed. The monoglycerides and fatty acids are reassembled into triglycerides. These triglycerides and other lipids are packaged into chylomicrons. The chylomicrons first enter the lymph system which then delivers them into the bloodstream.
emulsifiers and emulsification;
- lecithin is an example of an emulsifier
- emulsifiers have fat facing and water facing sides
- emulsifiers break fat globules into smaller droplets
