Lesson 5 Flashcards by Nat L

why are lipids necessary (3)

enhance flavor
increase absorption of fat-soluble vitamins and phytochemicals
contribute to satiety

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how much fat do we need to properly absorb fat soluble vitamins ?

20g fat

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what is fat ? what kind of tissue

fat is a connective tissue which supports other tissues

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what does visceral fat do ?

a fatty apron, covers and protects abdominal organs

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what does subcutaneous fat do ?

helps maintain body heat and cushions the body

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too much ____ fat increases chances of CVD

visceral

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fat provides more than __ the amount of energy of carbs and protein

twice

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what is the only form of energy stored for prolonged periods of time

fat

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what energy do we use when we are at rest

fat

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why is fat a better storage for than glycogen ?

because glycogen is too bulky and branched

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what is the downside to fat storage ?

we can store an unlimited amount and fat cells can enlarge to 1000x their original size

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what are the 4 main types of lipids ?

fatty acids
TG
phospholipids
cholesterol

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what are fatty acids made of ?

chain of carbon atoms attached to hydrogen atoms , with a methyl group at one end and an acid group at another

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what are triglycerides made of?

made of 3 fatty acid chains and a glycerol

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what are phospholipids made of ?

2 fatty acids

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how many fatty acids does cholesterol have ?

none

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why is cholesterol structure special ?

does not contain fatty acids

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short chain fatty acids are how long ?

2-4 C

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medium chain fatty acids are how long ?

6-12C

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long chain fatty acids are how long ?

14-24 C

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what kind of fatty acid is acetic acid ?

short chain (2C)

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what are the two fatty acid configurations ?

saturated (with hydrogen) (no double bonds)

unsaturated (double bonds causing kink in chain)

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what are the two kinds of unsaturated fatty acids, depending on amount of double bonds ?

monounsaturated and polyunsaturated

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what determines the behavior of the lipid ?

saturation level

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what are oils ?

lipids that are liquid at room temperature

what are oils predominantly composed of ?

unsaturated fatty acids

why is duck fat more solid than oil?

half the amount of saturated fatty acids, therefore between solid and liquid

what is considered the end of the fatty acid molecule

the carbon atom of the methyl group

what is another name for the carbon on the methyl group of the FA

the omega (w) end

if an 18 C fatty acid has two double bonds, the first of which from the methyl end is on the 6th carbon, then what is the name of that FA ?

18,2, w6

FA with 18C, 1 double bond from methyl end on 9th carbon, what is its name ?

18,1,w9

what is the word for omega 3 ?

alpha linolenic acid

what is the word for omega 6 ?

linoleic acid

why are w3 and w6 so important ?

the body cannot make double bonds in this particular position, therefore they are essential nutrients

is it easy to get w6?

yes

is it easy to get w3 ?

yes

what happens to w6 in the body ?

follows arachidonic acid pathway, crucial for synthesis of cell membranes

what happens to w3 in the body ?

becomes DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid)

what does DHA (docosahexaenoic acid) do ?

important for brain function and growth in infant as well as maintenance of brain function in adults

a deficit in DHA is associated with what

impaired learning

what is the role of EPA ?

reduces risk of CVD, blood pressure

can trans fats kill you ?

yes

how do you make a cis fat into a trans fat ?

by flipping the hydrogens to the other side by a hydrogenation process

all trans fats are man made. true or false ?

false butter isn't man made but otherwise, yes

why are trans fat products advantageous for the food industry ?

longer shelf life

in Denmark, you can go to jail if your food contains more than ___% trans fat

Health Canada has limited trans fat to what percentage ?

2% in margarine | 5% in all other foods

what is the most common lipid found in our food

triglycerides

95% of the fat we eat is in what form

99% of the fat of our body is stored as ____

is oil made of FA or TG?

how many acids does each oil molecule have ?

3 FA w/a glycerol

what is the FA composition of a triglyceride ?

can be saturated, MU, PU, doesn't matter but usually one predominates

what oil will be thicker - olive oil, with more MU FA, or corn oil, with more PU FA?

olive oil with MU FA because less bent FA

what happens when you deep fry a polyunsaturated oil ?

the double bonds in the FA break, losing hydrogen atom and leaving carbon with incomplete valence shell. unstable carbon becomes a free radical it turns rancid which may damage DNA

what is a free radical ?

incomplete valence shell

why is deep frying bad ?

creates free radicals

what is a solution to safer deep frying ?

using oils with more saturated fat (although have to be careful bc can contribute to CVD) and MU FA because they have less double bonds

what are phospholipids ??

diglyceride, in structure similar to TG. glycerol with 2 FA and then the third chain is phosphate (head)

are phospholipids water soluble ?

partially

what are the two ways phosphates differ ?

length and shape of FA and also the group attached to the phosphate

what is the most common phospholipid ?

lecithin (with choline group attached to the phosphate)

why is the partial solubility of phospholipids so important ?

because our cell membranes are made up of them

what is the cell membrane made of ?

phosholipid bilayer

which acid is present in phospholipid bilayer ?

arachidonic acid

in the kitchen what is the role of diglycerides ?

emulsifiers | eg oil + egg= mayo

what is cholesterol's origin ?

animals

lean meats or reduced dairy have low or high cholesterol ?

low

is cholesterol an essential nutrient ?

no, we make it

cholesterol is involved in the synthesis of which hormones ?

estrogen and testosterone

what are the 2 key cholesterol functions ?

- vitamin D synthesis | - digestion and absorption of lipids (bile)

what digestive thing contains cholesterol ?

bile

what begins to melt fat in mouth ?

lingual lipase and warmth

what does bile contain (3)

cholesterol, lecithin (phospholipid), and salts

what is the role of bile ?

breaks down fat into micelles

what does pancreatic lipase do ?

breaks down TG into FA and MG

how do short and medium chain FA get absorbed and to the liver?

simply cross membrane and leave through hepatic portal vein

how do long chain FA get absorbed and then leave the SI?

cross into epithelium as micelles, and then get packaged as chylomicrons and leave through lacteal vessel into subclavian vein

what are chylomicrons ?

lipoprotein

what does a lipoprotein consist of ?

interior of TG, cholesterol, and fat soluble vitamins surrounded by phospholipids with the tails pointing towards center, where lipids are, and the polar heads sticking out like a golf ball, allowing it to dissolve in water

what do chylomicrons transport and contain mostly ?

dietary TG mostly

VLDL is made by what

liver

VLDL is mostly made of what

what is a lipoprotein that is TG low and cholesterol rich ?

LDL

which lipoprotein has the most protein ?

HDL

what is the role of LDL

delivers cholesterol to cells

what does HDL do ?

take cholesterol from cells and return to liver

what disease was responsible for 32% of deaths in Canada ?

CVD

what is the pathophysiology of CVD?

begins with inflammation of blood vessels, and then the immune response causes plaque deposits

why is it important to increase soluble fiber intake

will carry bile to be eliminated, getting rid of cholesterol

what are three ways of reducing risk of CVD ?

soluble fiber AMDR 20-35% omega 3s 1.6g/day for men, 1.1g for women

what do statins do ?

interfere with body's cholesterol production

what does cholecystokinin do ?

secreted by SI | stimulates release of bile

does a lot of fat digestion happen in stomach ?

there is gastric lipase but still most is in SI

what is enterohepatic circulation ?

bile goes back to liver or is excreted

what is the principal end product of fat digestion ?

monoglycerides

what are the largest and least dense lipoproteins ?

chylomicrons

what do chylomicrons mostly transport ?

diet derived lipids (so mostly TG)

what happens to chylomicrons once they have done their job ?

chylomicron remnants removed from blood and the liver cells dismantle them

where are VLDL produced ?

liver

what is the difference between VLDL and LDL when it becomes LDL ?

VLDL has more TG. however, as it loses TG and gives it to cells, it gets cholesterol as predominant lipid, and the lipoprotein density increases to LDL

Lesson 5 Flashcards

(101 cards)