Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Nutrition > Antioxidants > Flashcards

Antioxidants Flashcards

1
Q

Antioxidants definition

A

substances in foods that function in the body to protect against damage caused by free radicals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how are free radicals generated

A

through:
- normal physiological processes: when oxygen gains extra electron from the ETC

  • exposure to toxic substances: air pollution and cigarette smoke
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

antioxidant rich diet

A

decreases risk of many chronic diseases (CVD and cancer)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are free radicals?

A
  • molecules with one or more unpaired electron, makes the molecule unstable and highly reactive
  • attack vulnerable compounds in the body, stealing an electron in order to regain stability
  • second molecule now has an unpaired electron (becomes a free radical)….sets up chain reaction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

damage by free radicals

A

free radicals cause extensive damage within the body

  • widespread damage to PUFAs in lipoproteins
  • cell membranes, cell proteins and DNA/RNA
  • damage linked to: cell damage, diseases (CVD and cancer, and aging
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

oxidative stress definition

A

condition in which the production of oxidants and free radicals exceeds the body’s ability to defend itself

damage by free radicals = oxidative stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

oxidative stress can lead to…

A

aging and development of several chronic diseases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

free radicals: first line of defense

A

system of enzymes that:

  • limit free radical formation
  • disarm the most harmful oxidants
  • these systems depend on the minerals selenium, copper, manganese, iron, zinc
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Free radicals: second line of defense

A

dietary antioxidants:

  • most notably: vitamins C, E, and beta-carotene
  • some phytochemicals have antioxidant properties
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

4 steps of how antioxidants work

A
  1. limiting free radical formation
  2. scavenging or quenching free radicals
  3. repairing the damage caused by free radicals
  4. supporting healthy immune function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

roles of vit. C (Ascorbic Acid)

A
  • helps to form collagen
  • potent antioxidant
  • assists in synthesis and conversion of serval hormones (thyroxin) and nuerotransmitters (serotonin)
  • aids in absorption of iron
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

the 5 antioxidant properties of Vit. C

A
  • electron donor (capable of scavenging free radicals)
  • restores vitamin E to its active state
  • reduces nitrosamines to harmless form
  • protects against effects of environmental contaminants and cigarette smoke
  • supports immune function
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

vit. C deficiency: Early symptoms

A
  • gums bleed easily (scorbutic gums)

- pinpoint hemorrhages in capillaries just under the skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Vit. C deficiency: prolonged

A

scurvy

  • further hemorrhaging & anemia
  • muscle degeneration
  • dry scaly skin, poor wound healing
  • frequent infections

completely curable if caught early - poses little threat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

link between nutrition and scurvy

A

mid 1700’s - British sailors - limited diet, no provisions to prevent spoilage, many became very ill
lead to discovery of “anti-scorbutic factor” in citrus fruits which was later isolated as vitamin C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Vit. C RDA

A

75mg F

90mg M

increase 35mg in smokers

17
Q

Vit. C sources

A

citrus fruits, peppers, dark green veggies, cantaloupe strawberries, tomatoes

18
Q

Vit. C toxicity

A

supplements
- nausea, abdominal cramps, diarrhea
can cause Fe overload
pro-oxidation?

19
Q

Vit. C absorption

A

limited absorption above 200 mg, most will be lost in urine

intake above UL(2000 mg) = toxic symptoms

20
Q

Vit. C and the common cold

A

no consistent effect on duration or severity

minimal to no impact on the duration of common cold
“no meaningful benefit”

21
Q

Vit. E (tocopherol) roles

A
  • potent antioxidant

- protection of cell membranes, polysaturated fats

22
Q

Vit. E deficiency

A

deficiency is rare - usually associated with diseases of fat malabsorption

  • damage to cell walls cause RBCs to break open leading to hemolytic anemia
23
Q

Vit. E RDA

A

15mg/day

24
Q

Vit. E sources

A

polyunsaturated oils, leafy greens, whole grains, eggs, nuts & seeds

25
Q

Vit E. antioxidant properties

A
  • alpha-tocopherol ( boosts the immune system and helps keep blood clots from forming)
  • capable of scavenging free radicals
  • protects against damage to arterial walls
  • prevents LDL oxidation and oxidation of PUFAs in cell membranes
26
Q

Vit E prolonged deficiency

A

results in nerve damage

27
Q

Vit E. and Performance

A

no long-term studies and no evidence of improved performance

some research say PA increases oxidative stress (increase O2 consumption - source of free radicals)

Vit E supplements MAY prevent oxidative damage to muscles (especially in extreme environments)

BUT regular exercise increases antioxidant enzymes

28
Q

Beta-Carotene abd Vit. A roles

A
  • both have antioxidant properties
  • fat soluble - prevents LDL oxidation and damage to PUFAs
  • scavenges free radicals
  • beta-carotene: relatively weak antioxidant
    compared to vitamins C & E, other phytochemicals
29
Q

3 forms of Vit. A active in the body

A

retinol (main transport/storage form)
retinal
retinoic acid

30
Q

Vit. A roles in the body

A

key role in vision

sexual reproduction

maintenance of epithelial cells

growth (bones and teeth)

immunity

Vit. A = “jack of all others” involved in a wide range of physiological processes

31
Q

Vit. A and Vision: 2 indispensable roles in eye

A
  • aids in maintenance of cornea

- participates in conversion of light energy to nerve impulses at the retina

32
Q

Vit. A deficiency symptoms

A
  • night blindness
  • impaired immunity
  • stunted growth
  • hyperkeratosis - damage to epithelial cells
  • deficiency effects 250 M children worldwide
33
Q

Vit. A and Beta carotene RDA

A

RDA expressed in retinol activity equivalents
reflecting that vitamin A can be synthesized from beta-carotene (provitamin A)

700 ug - Female

800 UG - Male

34
Q

Vit. A sources

A

liver, fish, milk, butter, eggs

35
Q

b-carotene sources

A

carrots, pumpkin, sweet potato, cantaloupe, spinach

36
Q

Vit. A and Beta carotene UL

A

3000ug

excessive vit. A is teratogenic (

Nutrition (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions