chapter 5 - lipids

Question 1

what are fats

Answer 1

lipids

greasy substances that arents soluble in water

solbue in some solvents like ether, benzene, chloroform

provide concentrated source of energy (9 cal per gram)

fat-rich foods are more expensive

composed of C, H, O w substantially less O

Question 2

function of fats

Answer 2

functioning and structure of body tissues

cnecessaryt part of cell membranes (cell walls)

contain essential fatty acids and carriers for fat-solbuel vitmains A,D, E, and K

provides energy when one cant eat

adipose tissue protects organs and bones from injury by serving as protective padding and support

body fat also = insulations

fats = satiety after meal bc flavor and slow rate of digest ion

Question 3

what are food sources for fats

Answer 3

animal foods: red meats, higher fat poultry cuts w skin like thigh and wing, whole, low-fat and reduced fat milk, cream, butter, cheeses made with cream, egg yolks, fatty fish like tuna and salmon (sat fat can raise cholesterol)

plant foods: cooking oil from olives, sunflowers, safflower, seasme seeds, corn, peanuts, canola oil, soubygeans, margarine, salad dressing, or mayo, nuts, seeds, avocadoes, coconuts, and cocoa butter

Question 4

deficiency of fat signs

Answer 4

eczema
weight loss
retarded growth

Question 5

visible fats

Answer 5

fats that are purhcased and used as fats, such as butter, margarine, lard, and coking oils

Question 6

invisible fats

Answer 6

found in other foods like meats, cream, whole milk, cheese, egg yoke, fried foods, pastries, avocadoes, and nuts

Question 7

what percent of lipids in body are triglycerides

Answer 7

95

Question 8

what are the lipids found in food and human body

Answer 8

triglycerides
phospholipids
sterols

Question 9

what are triglycerides

Answer 9

three fatty acids attached to glycerol

glycerol s iwater-soluble carb - alcohol that has three carbon atoms

Question 10

what are fatty acids

Answer 10

organic componds of carbon atoms to which hydrogen atoms are attached

Question 11

essentail fatty acids

Answer 11

necessary fats humans cant synthesized
must be obtained through diets
long chained poly unsaturated fatty acids derived from linoleic acid and linolenic acid

Question 12

typo families of EFAs

Answer 12

omega 3
omega 6hat

Question 13

what about omega 9 fatty acids?

Answer 13

necessary but nonessential bc body can product modest amount of EFAs r present

Question 14

what are another method of classification of fatty acids is by degree of situation w hydrogen atoms

Answer 14

saturated
monounsaturated
polyunsaturated

Question 15

what are saturated fats

Answer 15

each fatty acid carbon atom carries all hydrogen atoms possible

animal foods have more saturated fatty acids than unsaturated

plant food chocolate, coconut, palm oil , and palm kernel oils have more saturated fatty acids

solid at room temp

no more than 10% of total daily cal should be unsaturated

AHA said less than 7% w 5-6% if lipids are high nd risk for heart disease

Question 16

what are monounsaturated fats

Answer 16

one place among carbon where fewer hydrogen atoms

ex: olive oil, peanut oil, canola oil, avocadoes, cashew nuts

lower amount of LDL if replacing saturated fats

20% of tail cal should be monounsaturated fats

Question 17

what are polyunsaturated fats

Answer 17

two or more places among carbon atoms w fewer hydrogen atoms then in saturated fats

point at which carbon-carbon double bonds occur in polyunsaturated fatty acid determine how body metabolizes it

two major fatty acids denote placement of double bonds are omega 3 and omega 6 fatty acids

usually soft or oil

less than 10% of total daily cal

Question 18

what is omega 3

Answer 18

reported to lower risk of heart disease
found in fish oils so inc of fatty fish intake

Question 19

what is omega 6

Answer 19

linoleic acid

cholesterol-lowering effect

use of supplements isn’t recommended

Question 20

foods containing polyunsaturated fats

Answer 20

cooking oils made from sunflower safflower or seasem seeds or from corn or soybeans, for margarines whose major ingredient is liquid veg oil and fisdh

Question 21

what are transfatty acids

Answer 21

produced when hydrogen atoms added to monounsaturated or polyunsaturated fats to produce semi-solid product like margarine and shortening

likely to contain high amt of TFA if partially hydrogenated vegetable oil is listed in first three ingredients on label

major source of TFAs are baked goods and foods eaten in restrauttnats

required to be on food label since 2006

inc LDLs and dec HDLs

inc risk of developing heart disease, stroke, and T2D

Question 22

what are hydrogenated fats

Answer 22

polyunsaturated veg oil to which h has been added commercially to make them solid at room temp

called hydrogenation: turn polyunsaturated veg oils into sat fats (margarine; soft margarine has less sat fat then firm margarine)

Question 23

what is cholesterol

Answer 23

sterol
not true fat byt fat-like substance in animal foods and body cells (doesn’t exist in plant foods

essential to synthesize bile, sex hormones, cortisone, vitamin D and thus necessary for every cell

body makes 800-1000 mg daily in liber

thought to be contributing factor in heart disease bc hypercholesterolemia is common in pt w atherosclerosis

blood levels shouldn’t be more than 200 mg/dL

Question 24

Where is cholesterol found

Answer 24

egg yolk, fatty meats, shellfish, butter, cream, cheese, whole milk, organ meats

Question 25

how to reduce serum cholesterol levels

Answer 25

reduce amt of total fat, sat fat, cholesterol and inc amt of monounsaturated fats, wt loss, and exercise solble dietary fiber bc cholesterol binds to fiber and is eliminated, preventing absorption in small intestines medication

Question 26

____ of ingested fats are digest

Answer 26

95%

Question 27

where does chemical digestion of fats occur

Answer 27

in small intestine where bile emulsified fats and pancreatic lipase reduce them to fatty acids and glycerol not in mouth, slightly in stomach through gastric lipase acting on emulsified fats (like in cream and egg yolk)

Question 28

what are lipoproteins

Answer 28

bile joins products of fat digestions and protein combines w final products of fat digestion to form lipoproteins which carry fat to body cells by way of the blood

Question 29

classifications of lipoproteins

Answer 29

chylomicrons very low desntiy lipoproteins (VLDLs) LDLs HDLs

Question 30

what are chylomicrons

Answer 30

first lipoprotein identified after eating largest and lightest 80-90% triglycerides lipoprotein lipase breaks down triglycerides into free fatty acids and glycerol The protein and phospholipid exterior of a chylomicron enables the fat housed in the core of the chylomicron to travel in the water-based blood

Question 31

what are very low density liporproteins

Answer 31

made primarily by liver cels and are 55-65% triglycerides carry triglycerides and other lipids to all cells as VLDLs lose triglycerides they pick up cholesterol from other lipoproteins and become LDLs - become more dense

Question 32

what are LDLs

Answer 32

approx 45% cholesterol w few triglycerides most of blood cholesterol from liver to cells >130 mg/dL of LDL contribute to atherosclerosis bad cholesterol

Question 33

what are HDLs

Answer 33

carry cholesterol from cell to liver for excretion <40 mg/dL is dangerous >60 mg/dL is protective against heart disease good cholesterol inc w exercise, wt maintenance, and giving up smoking

Question 34

liver role in fat metablism

Answer 34

hydrolyzes triglycerides and form new ones as needed metabolism of fat occurs in cells (fatty acids r broken down to CO2 and water, releasing energy) portion of fat not needed immediately stored as adipose tissue CO2 and water are byproducts that are removed from body

Question 35

how to determine if item is necessaty for health

Answer 35

not included in Recommended Dietary Allowance (RDA), Dietary reference intakes (DRIs), or Adequate Intake (AI)

Question 36

what is lectin

Answer 36

fatty substance classified as phospholipid found in both plant and animal foods synthesized in liver natural emulsifier that transports fat in bl;oodstream used commercially to make food products smooth while some health food salespersons promote lecithin can prevent CV disease this hasn't been scientifically proven

Question 37

olestra

Answer 37

olestra - made form sugar and fatty acids approved by FDA for snack foods (potatoes chips, tortiall chips, and crackers) gov require food labels indicate olestra inhibits absorption of some vitamin and other nutrients fat-solbule vitamins A,D,E, and K have been added to foods containing olestra has no cal but cause cramps and diarrhea

Question 38

what is simplesse

Answer 38

fat alternative made from egg white or milk protein and contains 1.3 kcal/g used only in cool foods like icre cream bc it becomes thick or gels when heated not available for home use

Question 39

what is oatrim

Answer 39

carb based and derived from oat fiber heat stable and used in baking but not frying manufactures have used carb based compounds for years as thickeners provides cal but significantly less fat

Question 40

concern among nutritionists about fat alternatives

Answer 40

used in place of nutritious foods that provide vitmains, minerals, proteins and carb

Question 41

min amout of fat

Answer 41

no specific dietary requirements for fats is included in RDA and DRIS but deficiency symptoms if less than 10%

Question 42

fat deficiency in infants and IV feedings

Answer 42

in inftants fed formula lacking essential fatty acid linoleic acid and in people on IV feedings lacking linoleic acid can develop eczema, growth retardation, and wt loss

Question 43

what does excess fat lead to

Answer 43

obesity heart diease assocated w colon, breast, uterus, and prostate cancer

Question 44

Food and Nutrition Board's Committee on Diet and Health rec how much fat

Answer 44

30% of total cal

Question 45

what does AHA rec about fat

Answer 45

7% sat fat 10% polyunsaturated fats 20% monounsaturated fats

Question 46

according to mayo clinic what percent of cal in us dieet derived from solid fats and sugar

Answer 46

35%

Question 47

Fatty acids can be saturated or unsaturated. Saturated fatty acids have no double bonds in their chemical structure. They have a full load of hydrogen atoms. An unsaturated fatty acid has at least one double bond between two carbon atoms in each molecule. If a double bond is broken, two hydrogen atoms can be added to the molecule. The number of double bonds and hydrogen atoms in the fatty acid chain determine the degree of saturation. A monounsaturated fatty acid has only one double bond between carbon atoms. A polyunsaturated fatty acid has two or more dou-ble bonds (Figure 7.2).

Question 48

Hydrogenation

Answer 48

process of breaking the double carbon bonds in an unsaturated fatty acid and adding hydro-gen break liquid oils to solid fat creates trans fat

Question 49

rancid

Answer 49

describes a food oil in which the fatty acid molecules have combined with oxygen. This causes them to break down, and the oil spoils. Rancid oils have an unpleasant smell and taste.

Question 50

Lecithin

Answer 50

is a phospholipid that is made by the liver, so it is not essential to the diet. Lecithin is also found in many foods of animal origin, including egg yolks. Lecithin, like other phospholipids, is an emulsifier. An emulsifier is a substance that can mix with both water and fat. For example, egg yolk acts as an emulsifier in mayonnaise to prevent the oil and vinegar from separating. The lecithin in the egg yolk keeps the oil particles suspended in the watery vinegar. In the body, lecithin is part of cell membranes.

Question 51

Phytosterols

Answer 51

compounds from plants that are similar in structure to cholesterol include plant sterols and stanols can only be obtained through dietary sources. They are naturally present in small quanti-ties in many fruits, vegetables, nuts, seeds, cereals, legumes, vegetable oils, and other plant sources help lower LDL cholesterol levels and the risk for heart disease

Question 52

About____ of adipose tissue is just under your skin.

Answer 52

half

Question 53

The brain is nearly____ percent fat

Answer 53

60

Question 54

ruminants

Answer 54

Trans fats occur naturally in food from ruminants (animals that chew cud) such as cows, sheep, and goats