Antioxidants & Phytochemicals Flashcards
1
Q
Antioxidants:
A
chemicals that protect cells from damage from oxidation
2
Q
Types of antioxidants
A
- vit e
- vit c
- beta-carotene
- vit a
- selenium
3
Q
stable atoms contain an even number of ____
A
paired electrons
4
Q
Free radical:
A
an atom that has lost an electron and is left with an unpaired electron
5
Q
Free radicals are ____ _____ and can cause damage to ____ in the cell
A
highly reactive, molecules
6
Q
many metabolic process involve ___ reactions and can produce free radicals
A
oxidation
7
Q
free radicals are also produced by:
A
- immune responses to allergens, infections
- pollution
- ultraviolet light
- toxic substances
8
Q
free radicals cause damage to…
A
- cell membranes
- low-density lipoproteins (LDL)
- proteins in the cell
- genetic material (DNA)
9
Q
diseases linked to free radical production
A
- cancer
- diabetes
- arthritis
- catarats
- heart disease, kidney
- parkinsons
- alzheimers
10
Q
antioxidants can function in different ways:
A
- some vitamins donate their electrons to free radicals to stabilize them
- some minerals act (as co-factors!) with complex antioxidant enzyme systems to destroy free radicals, e.g. - superoxide dismutase; catalase; glutathione peroxidase
11
Q
other compounds help stabilize free radicals…such as:
A
beta-carotene, other phytochemicals
12
Q
vitamin E is a fat-soluble vitamin made of:
A
- tocotrienol (inactive portion)
- tocopherol (active portion)
13
Q
function of vitamin E
A
- primary role is antioxidant
- protects poly-unsaturated fatty acids (PUFAs)
- protects low-density lipoproteins (LDLs)
14
Q
Good sources of Vitamin E
A
- raisin bran cereal
- sunflower seeds
- marina sauce
- avocodo
- canola oil
- peanuts and peanut butter
- spinach
15
Q
RDA for vit E
A
15mg alpha-tocopherol for M&W
16
Q
what if you consume too much vit E?
A
- toxicity is uncommon
- can interefre with anticoagulant meds
- increased risk of hemorrhagic stroke
17
Q
Not enough consumption of Vit E?
A
- deficiencies are uncommon
- can result in erythrocyte hemolysis, anemia
18
Q
Vitamin C is?
A
water-soluble vitamin that must be consumed in human diet
19
Q
Functions of Vitamin C?
A
- antioxidant in extracellular fluid and is important in lungs and stomach
- regenerates vit E
- synthesis of collagen
- prevents the disease scurvy
- enhances immune system
20
Q
Vit C reccommended intake?
A
- 90mg/day for M; 75 for W
- smokers need extra 35g
21
Q
Good sources of vitamin c:
A
strawberries, grapefruit juice, kiwi, orange, broccoli, sweet potato, bell peppers, pineapple, tomatoes
22
Q
Beta-carotene is:
A
- in the class of chemicals called carotenoids
- a provitamin
23
Q
Provitamins are:
A
inactive precursors that must be converted to active forms in the body
24
Q
beta-carotene is the precursor of ____
A
retinol
25
Functions of beta-carotene:
- weak antioxidant
| - effective against oxidation in cell membranes and LDLs
26
Carotenoids in general are known to..
- enhance immune system
- protect skin from damage by UV light
- protect eyes from damage
27
beta-carotene is not considered an ____ ____
essential nutrient
28
only absorb ___% of the carotenoids in foods. Cooking increased ability to ___&_____
20-40, digest & absorb
29
sources of beta-carotene:
pumpkin, sweet potato, spinach, kale, carrots. cantalouple, broccoli
*NO RDA!*
30
ATBC study:
M smokers - beta-carotene intake increased # of deaths
| - lung cancer, heart disease, and stroke...esp. strong in those w/ high alcohol intake
31
Vitamin A is:
fat-soluble vitamin
32
excess vitamin A is stored in the:
liver, adipose tissue, kidneys, and lungs
33
Three active forms of Vitamin A:
- retinol
- retinal
- retinoic acid
34
Retinol functions:
vision, sexual reproduction, bone health, immune function
35
Retinal functions:
same as retinol
36
Retinoic acid functions:
cell differentiation, bone health, immune function
37
Consequences of consuming too much vitamin A:
- highly toxic, esp. from supps
| - birth defects & permanent damage to liver and eyes
38
Not enough Vit A consumption?
- night blindness most common effect
39
Sources of Vitamin A:
pumpkin, carrots, sweet potato, asparagus, oatmeal, raisin bran, cheese, ricotta, whole milk, broccoli
40
RDA for vitamin A:
900 ug/day M; 700 W
41
what is selenium?
trace mineral found in a few amino acids in the body
42
functions of selenium
- antioxidant; part of glutathione peroxidase enzyme system
| - production of thyroxine - thyroid hormone
43
What if you consume too much selenium?
- selenium toxicity (brittle hair, nails, skin rashes) can result from supps
- skin rashes, vomiting, damage of liver
44
Not enough selenium consumption causes?
- Keshan disease - a heart disorder
| - kashin-Beck disease - arthritis
45
Sources of Selenium:
halibut, tuna, couscous, cheese, ricotta, skim milk, mixed nuts, pork loin, spaghetti, turkey
46
RDA for selenium:
55ug/day
47
Cofactor:
compound needed for proper functioning of an enzyme
48
3 cofactors for the superoxide dismutase enzyme antioxidant system:
copper, zinc, manganese
49
cofactor for the catalase antioxidant system
Iron
50
Cancer:
group of related diseases characterized by cells growing out of contol
51
Cancer is composed of three steps:
- initiation
- promotion
- progression
52
Initiation:
a carcinogen causes a mutation in the DNA of a normal cell
53
Promotion:
cell with mutation in DNA divides repeatedly
54
Progression:
cancer cells invade surrounding tissues and spead to other sites in body
55
Cancer in Canada:
- 39% of W; 45%M will develop cancer
| - 2nd leading cause of death
56
Major factors of cancer:
- tobacco use
- sun exposur
- environmental and occupational exposure
- nutrition
- physical activity
57
Antioxidants may reduce risk of cancer by:
- enhancing immune system
- inhibiting growth of cancer cells
- preventing oxidation damage to cells
58
Phytochemicals:
- naturally occurring chemicals in plants
- biologically active in the body
- generally only available in whole foods
- in the lab, exhibit clear cancer prevention properties
59
Functions of phytochemicals:
- reduce inflammation
- enhance activity of some enzymes
- slow cancer tumour growth
- enhance immune function (antibacterial and antiviral agents)
- lowering blood lips & pressure
60
eating lots of phytochemical rich foods reduces risk of:Card
- CV disease
- Cancer
- Diabetes
- Alzheimer's
- cataracts
61
Cardiovascular Disease (CVD)
- leading cause of death in Canada
| - heart disease, hypertension, atherosclerosis
62
Risk factors of CVD
smoking, obesity, hypertension, high&low LDL levels, inactivity, diabetes
63
Antioxidants may reduce CVD risk by:
- preventing oxidative damage to LDL
- Acting as an anticoagulant to prevent blood clots (Vit E)
- Reducing low-grade-inflammation - newly identified risk
64
____&____ important to help reduce damage to vessels
Vitamin E and lycopene
65
Those who eat lots of ___&___ show decreased risk of CVD
fruits and vegetables
66
process of aging is associated with what?
increased oxidative damage and reduced activity of antioxidant enzyme systems
67
Two age-related diseases that may be prevented by antioxidants?
- Macular degeneration
| - Cataracts
68
Macular degeneration:
deterioration of the macula, the center of the retina
69
cataracts:
damaged regions of the lens of the eye causing cloudy vision
70
nucleus:
- positively charged , central core of an atom. two types of particles - protons and neutrons bound tightly together. atomic mass
71
electron
negatively charged particle orbiting nucleus of atom
72
oxidation
chemical reaction in which molecules of a substance are broken down into their component atoms. during oxidation, atoms involved lose electrons
73
exchange reaction
loss and gain of electrons
74
____ ____ have an even number of electrons orbiting in pairs at successive distances (called shells or rings) from the nucleus
stable atoms
75
when a stable atom loses electron during oxidation, it is left with an __ number of electrons in its outermost shell
Also known as:
odd
- unpaired electron
76
free radical
a highly unstable atom with an unpaired electron in its outermost shell
77
our body uses ___&___ to generate the energy (ATP) it needs
hydrogen and oxide
78
free radicals are also formed from other physiologic processes, such as when the _____ produces ____ to fight allergens or infections
immune system, inflammation
79
Other factors that cause free radical formation include exposure to:
- air pollution
- UV rays from the sun
- radiation
- tobacco smoke
- industrial chemicals
- abestos
80
one of the most significant sites of free radical damage is the
cell membrane
81
free radicals that form within the _____ ____ of cell membranes steal electrons from the stable ____ ___
phospholipid bilayer, lipid heads
82
stable-line up of lipid heads allows cell membranes to keep
water out
83
when lipid heads are destroyed, the cell membrane can no longer
repel water
84
the loss of ___ ___ causes damage to the cell and to all systems affected by the cell
cell integrity
85
Damage to LDLs and cell proteins disrupts the transport of substances into and out of cells and alters ____ ____
cell function
86
defective DNA results in faulty
protein synthesis
87
free radicals also promote _____ and the formation of clots, both of which are risk factors for _____
blood vessel inflammation, CVD
88
antioxidant vitamins work independently by
donating their electrons or hydrogen atoms to free radicals and to stabilize them and reduce the damage caused by oxidation
89
cofactors work to break down ___ that have become oxidized
fatty acids
90
cofactor
a mineral or other substance that is needed to allow enyzmes to function properly
91
tocopherol
the active form of vitamin E in our body
92
one of the fat soluble vitamins
Vitamin E
93
dietary fats carry vitamin e from our intestines through the ____ system and eventually transport it to our cells
lymphatic
94
about 90% of vitamin e in our body is stored in our ____ and the remaining is found in _____
adipose tissue, cell membranes
95
vitamin e is two seperate familes of compounds, known as the ____&____
tocotrienols and tocopherols
96
RDA for Vit E (fat soluble)
M&W = 15mg alpha-tocopheral
97
RDA for Vit C (water soluble)
W= 75mg, M=90mg
98
primary function of vit E is as an _____: it donates an electron to free radicals, stabilizing them and preventing them from destabilizing other molecules
antioxidant
99
once vitamin E is ____, it is either excreted from the body or recycled back into active vitamin e through the help of other antioxidant nutrients, such as ______
oxidized, vitamin C
100
In addition to protecting our PUFAs and LDLs, vitamin E protects the membranes of our ____ from oxidation and plays a critical role in protecting our lungs
RBC's
101
Vitamin E is critical for normal fetal and early childhood development of ___&____
nerves and muscles
102
Vitamin E improves the absorption of this vitamin if its dietary intake is low
Vitamin A
103
the most important medication that interacts negatively with vitamin E are
anticoagulants (aspirin) - stop blood from clotting excessively
- can lead to uncontrollable bleeding
104
vitamin E deficiencies are uncommon because
it is a fat soluble, so we typically store adequate amounts in our fatty tissues
105
vitamin e deficiencies are usually a result of diseases that cause
malabsorption of fat
106
two forms of vitamin C:
ascorbic acid and dehydroasorbic acid
107
Most animals can make their own vitamin C from ___. humans and guinea pigs are two groups that cannot synethsize their own vitamin c and must consume it in their diet
glucose
108
one reaso that vit c prevents scurvy is that it assits in the synethesis of
collagen
109
collagen, a protein, is a critical component of all connective tissues in the body, including:
bone, teeth, skin, tendons, blood vessels
110
collagen assists in preventing bruises, and it ensures proper would healing, as it is a part of scar tissue and a component of the tissue that mends ____
broken bones
111
vitamin c may also be involved in the synthesis of other components of connective tissues, such as ____&____
elastin and bone matrix
112
In addition to connective tissues, vit c assists in the synethesis of
dna, bile, neurotransmitters (seretonin) and carnitine, which transports long-chain fatty acids from the cytosol into the mitochondria for energy production
113
vitamin c also helps ensure that appropriate levels of thyroxine, a hormone produced by the thyroid gland, are produced to support basal metabolic rate and to maintain ______
body temperature
114
other hormones that are synethesized with assistance from vit c include
epinephrine, norepinephrine, and steroid hormones
115
what are the best sources for vitamin C?
fruits and vegetables
116
the forms of cooking that are least likely to compromise vit c content of foods a
restreaming, microwaving, stir-frying
117
megadose
a dose of a nutrient that is 10 or more times greater than the reccommended amout
118
an excess accumulation of iron in the body is called
hemochromatosis
119
taking too much vit c if you have a pre-existing kidney disease can lead to
kidney stones
120
pro-oxidant
- nutrient that promotes oxidation. it pushes balance of exchange reactions toward oxidation, which promotes free radicals
121
provitamin
inactive form of a vitamin that the body can convert to an active form. eg. beta-carotene
122
six most common carotenoids found in human blood
- alpha-carotene
- beta carotene
- beta cryptoxanthin
- lutein
- lycopene
- zeaxanthin
* *body can only convert first three to retinol*** known as provitamin A carotenoids
123
retina
delicate, light-sensitive membrane lining the inner eyeball and connected to the optic nerve. contains retinal
124
rhodospin
light sensitive pigment found in rod cells that is formed by retinal and opsin
125
cell differentiation
- important role of vit a in which immature, undifferentiated stem cells develop into highly
126
when light hits retina, a reaction occurs in which rhodospin is split into ____&____
retinal and rhodspin - rod cells to lose colour and retinal and rhopspin change shape
127
the cone cells of retina, which are effective in brightligh, use retinal to interpret different _____ of light as different colours
wavelengths
128
selenium is a
trace mineral found in soil
129
selenium in our body is found in
amino acids
130
selenomethionine is
storage form for selenium
131
selenocysteine
active form of selenium
132
selenium is critical component of the
glutathione peroxidase antioxidant enzyme
