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nutrition > Antioxidants & Phytochemicals > Flashcards

Antioxidants & Phytochemicals Flashcards

1
Q

Antioxidants:

A

chemicals that protect cells from damage from oxidation

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2
Q

Types of antioxidants

A
  • vit e
  • vit c
  • beta-carotene
  • vit a
  • selenium
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3
Q

stable atoms contain an even number of ____

A

paired electrons

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4
Q

Free radical:

A

an atom that has lost an electron and is left with an unpaired electron

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5
Q

Free radicals are ____ _____ and can cause damage to ____ in the cell

A

highly reactive, molecules

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6
Q

many metabolic process involve ___ reactions and can produce free radicals

A

oxidation

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7
Q

free radicals are also produced by:

A
  • immune responses to allergens, infections
  • pollution
  • ultraviolet light
  • toxic substances
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8
Q

free radicals cause damage to…

A
  • cell membranes
  • low-density lipoproteins (LDL)
  • proteins in the cell
  • genetic material (DNA)
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9
Q

diseases linked to free radical production

A
  • cancer
  • diabetes
  • arthritis
  • catarats
  • heart disease, kidney
  • parkinsons
  • alzheimers
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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
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11
Q

other compounds help stabilize free radicals…such as:

A

beta-carotene, other phytochemicals

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12
Q

vitamin E is a fat-soluble vitamin made of:

A
  • tocotrienol (inactive portion)

- tocopherol (active portion)

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13
Q

function of vitamin E

A
  • primary role is antioxidant
  • protects poly-unsaturated fatty acids (PUFAs)
  • protects low-density lipoproteins (LDLs)
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14
Q

Good sources of Vitamin E

A
  • raisin bran cereal
  • sunflower seeds
  • marina sauce
  • avocodo
  • canola oil
  • peanuts and peanut butter
  • spinach
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15
Q

RDA for vit E

A

15mg alpha-tocopherol for M&W

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16
Q

what if you consume too much vit E?

A
  • toxicity is uncommon
  • can interefre with anticoagulant meds
  • increased risk of hemorrhagic stroke
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17
Q

Not enough consumption of Vit E?

A
  • deficiencies are uncommon

- can result in erythrocyte hemolysis, anemia

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18
Q

Vitamin C is?

A

water-soluble vitamin that must be consumed in human diet

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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
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20
Q

Vit C reccommended intake?

A
  • 90mg/day for M; 75 for W

- smokers need extra 35g

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21
Q

Good sources of vitamin c:

A

strawberries, grapefruit juice, kiwi, orange, broccoli, sweet potato, bell peppers, pineapple, tomatoes

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22
Q

Beta-carotene is:

A
  • in the class of chemicals called carotenoids

- a provitamin

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23
Q

Provitamins are:

A

inactive precursors that must be converted to active forms in the body

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24
Q

beta-carotene is the precursor of ____

A

retinol

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25
Q

Functions of beta-carotene:

A
  • weak antioxidant

- effective against oxidation in cell membranes and LDLs

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26
Q

Carotenoids in general are known to..

A
  • enhance immune system
  • protect skin from damage by UV light
  • protect eyes from damage
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27
Q

beta-carotene is not considered an ____ ____

A

essential nutrient

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28
Q

only absorb ___% of the carotenoids in foods. Cooking increased ability to ___&_____

A

20-40, digest & absorb

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29
Q

sources of beta-carotene:

A

pumpkin, sweet potato, spinach, kale, carrots. cantalouple, broccoli
NO RDA!

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30
Q

ATBC study:

A

M smokers - beta-carotene intake increased # of deaths

- lung cancer, heart disease, and stroke…esp. strong in those w/ high alcohol intake

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31
Q

Vitamin A is:

A

fat-soluble vitamin

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32
Q

excess vitamin A is stored in the:

A

liver, adipose tissue, kidneys, and lungs

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33
Q

Three active forms of Vitamin A:

A
  • retinol
  • retinal
  • retinoic acid
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34
Q

Retinol functions:

A

vision, sexual reproduction, bone health, immune function

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35
Q

Retinal functions:

A

same as retinol

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36
Q

Retinoic acid functions:

A

cell differentiation, bone health, immune function

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37
Q

Consequences of consuming too much vitamin A:

A
  • highly toxic, esp. from supps

- birth defects & permanent damage to liver and eyes

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38
Q

Not enough Vit A consumption?

A
  • night blindness most common effect
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39
Q

Sources of Vitamin A:

A

pumpkin, carrots, sweet potato, asparagus, oatmeal, raisin bran, cheese, ricotta, whole milk, broccoli

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40
Q

RDA for vitamin A:

A

900 ug/day M; 700 W

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41
Q

what is selenium?

A

trace mineral found in a few amino acids in the body

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42
Q

functions of selenium

A
  • antioxidant; part of glutathione peroxidase enzyme system

- production of thyroxine - thyroid hormone

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43
Q

What if you consume too much selenium?

A
  • selenium toxicity (brittle hair, nails, skin rashes) can result from supps
  • skin rashes, vomiting, damage of liver
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44
Q

Not enough selenium consumption causes?

A
  • Keshan disease - a heart disorder

- kashin-Beck disease - arthritis

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45
Q

Sources of Selenium:

A

halibut, tuna, couscous, cheese, ricotta, skim milk, mixed nuts, pork loin, spaghetti, turkey

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46
Q

RDA for selenium:

A

55ug/day

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47
Q

Cofactor:

A

compound needed for proper functioning of an enzyme

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48
Q

3 cofactors for the superoxide dismutase enzyme antioxidant system:

A

copper, zinc, manganese

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49
Q

cofactor for the catalase antioxidant system

A

Iron

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50
Q

Cancer:

A

group of related diseases characterized by cells growing out of contol

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51
Q

Cancer is composed of three steps:

A
  • initiation
  • promotion
  • progression
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52
Q

Initiation:

A

a carcinogen causes a mutation in the DNA of a normal cell

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53
Q

Promotion:

A

cell with mutation in DNA divides repeatedly

54
Q

Progression:

A

cancer cells invade surrounding tissues and spead to other sites in body

55
Q

Cancer in Canada:

A
  • 39% of W; 45%M will develop cancer

- 2nd leading cause of death

56
Q

Major factors of cancer:

A
  • tobacco use
  • sun exposur
  • environmental and occupational exposure
  • nutrition
  • physical activity
57
Q

Antioxidants may reduce risk of cancer by:

A
  • enhancing immune system
  • inhibiting growth of cancer cells
  • preventing oxidation damage to cells
58
Q

Phytochemicals:

A
  • 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
Q

Functions of phytochemicals:

A
  • reduce inflammation
  • enhance activity of some enzymes
  • slow cancer tumour growth
  • enhance immune function (antibacterial and antiviral agents)
  • lowering blood lips & pressure
60
Q

eating lots of phytochemical rich foods reduces risk of:Card

A
  • CV disease
  • Cancer
  • Diabetes
  • Alzheimer’s
  • cataracts
61
Q

Cardiovascular Disease (CVD)

A
  • leading cause of death in Canada

- heart disease, hypertension, atherosclerosis

62
Q

Risk factors of CVD

A

smoking, obesity, hypertension, high&low LDL levels, inactivity, diabetes

63
Q

Antioxidants may reduce CVD risk by:

A
  • preventing oxidative damage to LDL
  • Acting as an anticoagulant to prevent blood clots (Vit E)
  • Reducing low-grade-inflammation - newly identified risk
64
Q

____&____ important to help reduce damage to vessels

A

Vitamin E and lycopene

65
Q

Those who eat lots of ___&___ show decreased risk of CVD

A

fruits and vegetables

66
Q

process of aging is associated with what?

A

increased oxidative damage and reduced activity of antioxidant enzyme systems

67
Q

Two age-related diseases that may be prevented by antioxidants?

A
  • Macular degeneration

- Cataracts

68
Q

Macular degeneration:

A

deterioration of the macula, the center of the retina

69
Q

cataracts:

A

damaged regions of the lens of the eye causing cloudy vision

70
Q

nucleus:

A
  • positively charged , central core of an atom. two types of particles - protons and neutrons bound tightly together. atomic mass
71
Q

electron

A

negatively charged particle orbiting nucleus of atom

72
Q

oxidation

A

chemical reaction in which molecules of a substance are broken down into their component atoms. during oxidation, atoms involved lose electrons

73
Q

exchange reaction

A

loss and gain of electrons

74
Q

____ ____ have an even number of electrons orbiting in pairs at successive distances (called shells or rings) from the nucleus

A

stable atoms

75
Q

when a stable atom loses electron during oxidation, it is left with an __ number of electrons in its outermost shell

Also known as:

A

odd

  • unpaired electron
76
Q

free radical

A

a highly unstable atom with an unpaired electron in its outermost shell

77
Q

our body uses ___&___ to generate the energy (ATP) it needs

A

hydrogen and oxide

78
Q

free radicals are also formed from other physiologic processes, such as when the _____ produces ____ to fight allergens or infections

A

immune system, inflammation

79
Q

Other factors that cause free radical formation include exposure to:

A
  • air pollution
  • UV rays from the sun
  • radiation
  • tobacco smoke
  • industrial chemicals
  • abestos
80
Q

one of the most significant sites of free radical damage is the

A

cell membrane

81
Q

free radicals that form within the _____ ____ of cell membranes steal electrons from the stable ____ ___

A

phospholipid bilayer, lipid heads

82
Q

stable-line up of lipid heads allows cell membranes to keep

A

water out

83
Q

when lipid heads are destroyed, the cell membrane can no longer

A

repel water

84
Q

the loss of ___ ___ causes damage to the cell and to all systems affected by the cell

A

cell integrity

85
Q

Damage to LDLs and cell proteins disrupts the transport of substances into and out of cells and alters ____ ____

A

cell function

86
Q

defective DNA results in faulty

A

protein synthesis

87
Q

free radicals also promote _____ and the formation of clots, both of which are risk factors for _____

A

blood vessel inflammation, CVD

88
Q

antioxidant vitamins work independently by

A

donating their electrons or hydrogen atoms to free radicals and to stabilize them and reduce the damage caused by oxidation

89
Q

cofactors work to break down ___ that have become oxidized

A

fatty acids

90
Q

cofactor

A

a mineral or other substance that is needed to allow enyzmes to function properly

91
Q

tocopherol

A

the active form of vitamin E in our body

92
Q

one of the fat soluble vitamins

A

Vitamin E

93
Q

dietary fats carry vitamin e from our intestines through the ____ system and eventually transport it to our cells

A

lymphatic

94
Q

about 90% of vitamin e in our body is stored in our ____ and the remaining is found in _____

A

adipose tissue, cell membranes

95
Q

vitamin e is two seperate familes of compounds, known as the ____&____

A

tocotrienols and tocopherols

96
Q

RDA for Vit E (fat soluble)

A

M&W = 15mg alpha-tocopheral

97
Q

RDA for Vit C (water soluble)

A

W= 75mg, M=90mg

98
Q

primary function of vit E is as an _____: it donates an electron to free radicals, stabilizing them and preventing them from destabilizing other molecules

A

antioxidant

99
Q

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 ______

A

oxidized, vitamin C

100
Q

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

A

RBC’s

101
Q

Vitamin E is critical for normal fetal and early childhood development of ___&____

A

nerves and muscles

102
Q

Vitamin E improves the absorption of this vitamin if its dietary intake is low

A

Vitamin A

103
Q

the most important medication​ that interacts negatively with vitamin E are

A

anticoagulants (aspirin) - stop blood from clotting excessively
- can lead to uncontrollable bleeding

104
Q

vitamin E deficiencies are uncommon because

A

it is a fat soluble, so we typically store adequate amounts in our fatty tissues

105
Q

vitamin e deficiencies are usually a result of diseases that cause

A

malabsorption of fat

106
Q

two forms of vitamin C:

A

ascorbic acid and dehydroasorbic acid

107
Q

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

A

glucose

108
Q

one reaso that vit c prevents scurvy is that it assits in the synethesis of

A

collagen

109
Q

collagen, a protein, is a critical component of all connective tissues in the body, including:

A

bone, teeth, skin, tendons, blood vessels

110
Q

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 ____

A

broken bones

111
Q

vitamin c may also be involved in the synthesis of other components of connective tissues, such as ____&____

A

elastin and bone matrix

112
Q

In addition to connective tissues, vit c assists in the synethesis of

A

dna, bile, neurotransmitters (seretonin) and carnitine, which transports long-chain fatty acids from the cytosol into the mitochondria for energy production

113
Q

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 ______

A

body temperature

114
Q

other hormones that are synethesized with assistance from vit c include

A

epinephrine, norepinephrine, and steroid hormones

115
Q

what are the best sources for vitamin C?

A

fruits and vegetables

116
Q

the forms of cooking that are least likely to compromise vit c content of foods a

A

restreaming, microwaving, stir-frying

117
Q

megadose

A

a dose of a nutrient that is 10 or more times greater than the reccommended amout

118
Q

an excess accumulation of iron in the body is called

A

hemochromatosis

119
Q

taking too much vit c if you have a pre-existing kidney disease can lead to

A

kidney stones

120
Q

pro-oxidant

A
  • nutrient that promotes oxidation. it pushes balance of exchange reactions toward oxidation, which promotes free radicals
121
Q

provitamin

A

inactive form of a vitamin that the body can convert to an active form. eg. beta-carotene

122
Q

six most common carotenoids found in human blood

A
  • alpha-carotene
  • beta carotene
  • beta cryptoxanthin
  • lutein
  • lycopene
  • zeaxanthin
  • body can only convert first three to retinol** known as provitamin A carotenoids
123
Q

retina

A

delicate, light-sensitive membrane lining the inner eyeball and connected to the optic nerve. contains retinal

124
Q

rhodospin

A

light sensitive pigment found in rod cells that is formed by retinal and opsin

125
Q

cell differentiation

A
  • important role of vit a in which immature, undifferentiated stem cells develop into highly
126
Q

when light hits retina, a reaction occurs in which rhodospin is split into ____&____

A

retinal and rhodspin - rod cells to lose colour and retinal and rhopspin change shape

127
Q

the cone cells of retina, which are effective in brightligh, use retinal to interpret different _____ of light as different colours

A

wavelengths

128
Q

selenium is a

A

trace mineral found in soil

129
Q

selenium in our body is found in

A

amino acids

130
Q

selenomethionine is

A

storage form for selenium

131
Q

selenocysteine

A

active form of selenium

132
Q

selenium is critical component of the

A

glutathione peroxidase antioxidant enzyme

nutrition (10 decks)

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