Nutrition Chap 5- Lec 5 Midterm 1

Front 1

What are lipids? what are fats?

Back 1

diverse class of molecules that are insoluble in water.
•Fats are one type of lipid.
••Lipids (fats) do not dissolve in water.

Front 2

Which three types of lipids are present in food?

Back 2

Triglycerides
–Phospholipids
–Sterols

Front 3

Triglycerides:

Back 3

Composed of:
- Three fatty acid molecules
fatty acid: long chains of carbon atoms surrounded by hydrogen atoms

- one glycerol molecule:
3 carbon alcohol, backbone of triglyceride

Front 4

How do triglycerides differ from each other?

Back 4

Length: of carbon chain
- short, medium, or long

Level of Saturation:
- how many hydrogen atoms surround each carbon

Shape:

Front 5

saturated:

Back 5

hydrogen atoms on every carbon
- animal fats

Front 6

monounsaturated

Back 6

lack hydrogen atoms at one carbon have one double bond
- olive and canola oil

Front 7

polyunsaturarated

Back 7

lack hydrogen bonds at multpile carbons, more than one double bond
- flaxseed oils, soybean, walnuts

Front 8

Shape:

Back 8

detrmined by saturation of carbon chains and by the type of double bond

- satirated fatty acids can pack tightly together and are solid
-

Front 9

Cis and trans:

Back 9

- unsaturated regions can be arranged in different positions
cis- same side - natural (plant oils)
trans- opposite (much more linear. more artificial

Front 10

Hydrogenation:

Back 10

addition of hydrogen atoms to unsaturated fatty acids
- converts liquid fats into a more solid form
- used to create margarine from plant oil
- often creates trans fatty acids

Front 11

Phospholipids: composed of?
-

Back 11

Glycerol backbone
•2 fatty acids
•Phosphate
–Are soluble in water
–Are manufactured in our bodies so they are not required in our diet

Front 12

Sterols:

Back 12

Lipids containing multiple rings of carbon atoms.
–Are essential components of cell membranes and many hormones
–Are manufactured in our bodies and therefore are not essential components of our diet

- block cholestorol absorption (good thing)
- fruits, vegeies, nuts, legumes, soybeans

Front 13

Digestion of lipids: before SI

Back 13

Lipids are not digested and absorbed easily because they are insoluble in water.
•No digestion of lipids occurs in the watery environments of the mouth or stomach.
•Digestion of lipids begins in the small intestine.

Front 14

Digestion of lipids: in SI

Back 14

Bile is secreted from the gall bladder into the small intestine because of CCK and secretin
–Bile is produced by the liver and stored in the gall bladder
–Bile disperses fat into smaller fat droplets
–Pancreatic enzymes break fat into 2 separate fatty acids and a monoglyceride
- micelles transport lipid digestion products to the enterocytes of the small intestine for absorption

Front 15

What are fatty acids arranged as for absorption and trasnport

Back 15

Lipoprotients: sphericle compour in which fat cluster in the centre and phospholipids and proteinds form the outside of the sphere

Front 16

Chylomicron:

Back 16

A lipoprotein produced by cells lining the small intestine.
–Composed of fatty acids surrounded by phospholipids and proteins
–Soluble in water

absorbed by cells of the small intestine, then they
–travel through the lymphatic system
–are transferred to the bloodstream

Front 17

Short and medium chain fatty acids are absorbed.....?

Back 17

more quickly since they are not arranged into chylomicrons.

Front 18

What must triglycerides in the chylomicrons do before can enter body cells

Back 18

disassembled by lipoprotein lipase

Front 19

What 3 things can happen to triglycerides after entering body cells?

Back 19

–Used immediately for energy
–Used to make lipid-containing compounds
–Stored in liver and muscle cells

Front 20

What about the energy that lipids provide?

Back 20

Fat is very energy dense, containing 9 kcal per gram.
–Much of the energy used during rest comes from fat.
–Fat is used for energy during exercise, especially after glycogen is depleted.
–Fat is also used for energy storage.

Front 21

•Essential fatty acids

Back 21

- must be consumed in diet because they cannot be made by our bodes

Front 22

What are the two? describe.

Back 22

Alpha-linoleic acid(omega-3 fatty acid)
•Found in vegetables, fish and nutoils

Linoleic acid(omega-6 fatty acid)
•Found in vegetable and nut oils,
- converted to arachidonic acid = precurder to body regulation functions like blood clotting and BP

Front 23

What else do lipidds do? Which vitamins are fat soluble?

Back 23

–Vitamins A, D, E, and K are soluble in fat; fat is required for their transport

Front 24

What body functions is fat essential to?

Back 24

–Cell membrane structure
–Nerve cell transmissions
–Protection of internal organs
–Insulation to retain body heat

Front 25

Fats also contribute _____ and ______ to foods.

Back 25

•Fat providesflavour andtexture to foods.

Front 26

Fats also helps us fell satiated because: 2 reasons

Back 26

Fats are more energy dense than carbohydrates or protein
–Fats take longer to digest

Front 27

Tips on the type of fat that should be consumed;

Back 27

Saturated fat intake should be as low as possible.
–Trans fatty acids should be reduced to the absolute minimum.
–Most fat in our diets should be from monounsaturated fats (e.g., olive oil).

Front 28

Why should we keep our intake of saturated fat as low as possible? and no trans?

Back 28

- they increase risk of HD

Front 29

Visible vs. Invisible fats:

Back 29

- fats we see in our food or see added, butter, salad dressing, chicken skins

vs.

- hidden, such as backing good, marbeling in meat, fried

Front 30

What are the 2 Omega- 3 fatty acids? why so important?
- what are they? where are they found&

Back 30

Eicosapentaenoic acid (EPA):
•May reduce risk of death from a heart attack.
–Docosahexaenoic acid (DHA):
•Critical for development of central nervous system and retina of eyes
EPA and DHA are long chain polyunsaturated fatty acids found in fish and fish oils

Canada food guide recommends eating at least two serving of fish per week

Front 31

Fat replacers:

Back 31

substances used to replace the typical fats in food to reduce the amount of fat in the food

Front 32

Cardiovascular disease (describe) and fats (their effect):

Back 32

Dysfunction of the heart or blood vessels
–Can result in heart attack or stroke

- fat can promote CD or prevent

Front 33

•Risk factors for cardiovascular disease include:

Back 33

Being overweight
–Physical inactivity
–Smoking
–High blood pressure
–Diabetes

unmodifiable:
- age, history and gender

Front 34

Blood lipids include:
pg. 183

Back 34

Chylomicrons
–VLDLs –very low-density lipoproteins
–LDLs –low-density lipoproteins
•“bad cholesterol”
–HDLs –high-density lipoproteins
•“good cholesterol”

Front 35

Diet high in saturated fats:

Back 35

Decrease the removal of LDLs from the blood
–Contribute to the formation of plaques that can block arteries
–Increase triglyceride levels (chylomicrons and VLDLs)

Front 36

•Trans fatty acids:

Back 36

Increase blood LDL cholesterol levels and reduce blood HDL cholesterol levels
–Are abundant in hydrogenated vegetable oils (margarine, vegetable oil spreads)
–Should be reduced to the absolute minimum

Front 37

•How can fat intake protect against heart disease?

Back 37

Diets high in omega-3 fatty acids (along with moderate exercise) can increase HDL “good” cholesterol levels.

Front 38

Lifestyle changes that can help reduce or prevent cardiovascular disease:

Back 38

- maintain total fat intake
- decrease dietary saturated fat to less then 7% of total energy intake
- increase dietary intakes of whole grains, fruits and vegetables so that the total fibre it 20-30 grams a day
- maintain blood glucose
- eat throughout the day
- active
- healthy body weight