chapter 5 Flashcards
1
Q
fat in the canadian diet
A
- has declined
- fat intake comes from 2 groups: meat and alternatives and milk and alternatives
- 25% of fat comes from fast food and snack foods
2
Q
what are lipids
A
- molecules that are insoluble in water
- oils: liquid at RT
- fats: solid at RT
3
Q
types of lipids
A
- triglycerides
- phospholipids
- sterols
4
Q
triglyceride structure
A
- glycerol backbone and 3 fatty acids
- methyl group at omega end
carboxyl group at alpha end - saturated: no double bonds
- unsaturated: double bonds
5
Q
fatty acid length
A
- short: 2-4Cs
- medium: 6-10Cs
- long: 12+Cs
- a shorter chain has more liquid and is more water soluble
6
Q
saturation
A
- all single bonds
- MUFA: monounsaturated fatty acid - one double bond
- PUFA: polyunsaturated fatty acid - more than one double bond
- adding double bonds creates kinks in the fatty acid and changes shape
7
Q
cis vs. trans
A
- cis: bent chain, natural, sof t solid, healtheir
- trans: straight chain, solid, produced by hydrogenation, preserves shelf life
8
Q
hydrogenation
A
- addition of hydrogen atoms to unsaturated fatty acids
- makes liquid fats more solid
- raised blood cholesterol levels
- increased risk of heart disease
- sourced from food industry and ruminants
9
Q
essential fatty acids
A
- cant be made in body
- fatty acids with double bonds before 9th omega carbon
- typically alpha linoleic acid (omega 3) (veg and dish) and linoleic acid (omega 6) (veg and nuts)
- count from methyl end
10
Q
non essential fatty acids
A
- food supplies alpha-linolenic acid which converts to intermediate molecules which convert to DHA and EPA
- DHA and EPA convert back and forth
11
Q
EPA
A
- eicosapentaenoic acid
- may reduce death from heart attack
12
Q
DHA
A
- docosahecaenoicacid
- critical for development of nervous system and retina of the eyes
- early childhood brain development
- increases HDL cholesterol
13
Q
phospholipid structure
A
- glycerol + 2 fatty acids + phosphate group
- soluble in water and lipid
- phosphate group with N containing component in 3rd site
14
Q
phospholipid functions
A
- role in cell membranes
- receptors, enzymes, transporters
- lipid transport as part of lipoproteins
- emulsifiers
15
Q
lechithic - fat digestion
A
- emulsifiers
- found in egg yolk, wheat germ, peanuts, soy bean
- how water and oil can be mixed
16
Q
micelles
A
- small phospholipid molecules
- hydrophobic fatty acid tails grouped together
- water soluble segment on outside
17
Q
sterols
A
- liquid lipid found in plants and animals
- doesnt dissolve in water
- cholesterol: sterol only in animals
- plant sterols can help reduce cholesterol in body
18
Q
cholesterol
A
- made in liver
- part of cell membranes
- precursor to other substances: sterol hormones, vitamin d, bile acids
19
Q
cholesterol to sex hormones
A
- similar molecules, can be converted
20
Q
lipid digestion: mouth and stomach
A
- a bit
- mouth: lingual lipase
- stomach: gastric lipase
21
Q
lipid digestion: gallbladder
A
- bile
- emulsifying agents
22
Q
lipid digestion: small intestine
A
- pancreatic lipase
- emulsified by phospholipid
- digested by pancreatic lipase
- absorbed into intestinal cells and formed into chylomicrons and moved into lymphatic system
- bile is secreted from gallbladder to small intestine
- bile disperses fat into smaller fat droplets
- chylomicrons absorbed by cells in small intestine and then travel throguh lymphatic system and are then transferred to bloodstream
23
Q
chylomicrons
A
- inside intestinal cells, components join: triglycerides, cholesterol, phospholipids, protein carrier
- become lipoprotein and carry lipids around body
- called chylomicron after leaving intestinal cell
24
Q
very low density lipoproteins
A
- formed in liver
- deliver triglycerides in cells
- largest
25
Q
low density lipoproteins
A
- deliver cholesterol to cells
- associated with CVD
- results in atherosclerosis
26
Q
high density lipoproteins
A
- pick up cholesterol for moving and recycling
- smallest
27
Q
fat in the diet
A
- reduce trans and saturated fat intake
- total fat: max 35% of energy
- saturated fat: max 10% of energy
- need 2% of kcals as essential fatty acids
- athletes may need more carbs and less fat - 20-25%
28
Q
obesity
A
- high fat diets promote weight gain
- fat hidden in food
29
Q
heart disease risk factors
A
- high blood cholesterol
- high LDL and low HDL
- smoking
- high blood pressure
30
Q
c reactive protein (CRP)
A
- produced in liver, released during systematic inflammation-
- to reduce: consume fish high in omega 3s, alpha linolenic acid from plant sources, fibre
31
Q
homocysteine
A
- promotes inflammation
- inversely correlated with intake of folate, vit b6, b12
- reduce coffee intake
32
Q
mercury
A
- damages nervous system
- aquatic form: methyl mercury
- bunds to protiens in fish
- accumulates - bigger fish have more mercury
33
Q
fish consumption limitations
A
- limit consumption of swordfish, shark, tuna to 1 meal/week
- for kids and women of childbearing age: limit to 1 meal/month
- not for canned tuna
34
Q
grassy narrows FN
A
- fish was main source of food, lots of mercury
- pulp and paper mill released mercury into river
35
Q
pop
A
persistent organic pollutents
36
Q
pcb
A
polychlorinated byphenyls
- multiple health risks
- organic contaminent
- accumulate in fatty tissues of animals
37
Q
ddt
A
health risk questionable
- organic contaminent
38
Q
dixins and furans
A
chlorine atoms
- organic contaminent
39
Q
fish selection
A
- not predatory
- smaller
- wild
- ocean
- canned over fresh
40
Q
latest health canada advisory for canned tuna
A
- pregnant woment: up to 4 servings/week
- kids 1-4: up to 1 serving/weel
- kids 5-11: up t 2 serving/week
41
Q
latest health canada advisory for pred fish
A
- most: 150g/wk
- pregnant women: 150g/month
- kids 5-11: 125g/month
- kids 1-4 75g/month
