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Nutrition 3330 > 9 Antioxidants and Micronutrients > Flashcards

9 Antioxidants and Micronutrients Flashcards

1
Q

Fruits and Vege consumption known for decrease rates of?

A

Cancer and Disease

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2
Q

What attributes to fruit and vegetables nutritional benefit?

A

antioxidants

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3
Q

Micronutrients (essential) antioxidants

A 
Vitamins C, E
Selenium, Riboflavin, Niacin
Zinc, Copper, Manganese
Iron
Beta Carontene

(work together as co-enzymes)

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4
Q

Why do we need Antioxidants

A
  • Balance between Pro/Anti

- Oppose oxygen toxic effects

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5
Q

Purposes of oxygen

A

> 95% energy production

1-3% reactive oxygen species (need to be dealt with)

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6
Q

Oxidative stress

A

Imbalance

  • increase ROS production
  • decrease antioxidant intake

Severe
- Cell Damage

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7
Q

Whats considered cell damage?

Caused by?

A

Cellular mutations
Tissue Breakdown
Immune Compromise

  • caused by oxidative stress
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8
Q

Formation of free radicals

A

oxidative metabolism

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9
Q

What are free radicals

A

molecules with one or more UNPAIRED electrons

- very unstable, highly reactive

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10
Q

How to make free radicals stable?

A

Antioxidants steal electron from another to be stable

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11
Q

How do atoms bind?

- why does this make free radicals so bad?

A

Sharing of electrons

  • unpaired electrons of free radicals unstable and reactive
  • can set off a chain reaction
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12
Q

3 types of free radicals

A
  1. ROS - reactive oxygen species
  2. RNS - reactive nitrogren species
  3. R - other reactive radicals
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13
Q

Are free radicals normal?

A

Yes - normal product of cellular reactions

- have useful biological function

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14
Q

Types of ROS

A

Free Radicals

  • superoxide radical (O2-)
  • Hydroxy Radical (OH*)
  • Fatty acid peroxide radical (ROO*)
  • Nitric Oxide (NO*)

Unstable Molecules

  • Hydrogen Peroxide (H2O2)
  • Ozone (O3)
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15
Q

Useful functions of ROS

A

(produced by phagocytes)

  • defence mechanism
  • kill bacteria and fungi
  • inactivate viruses
  • inflammatory (sometimes over activated)
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16
Q

Accidental production of ROS generation

A

Electron Transport Chain

- some electrons escape and spontaneously react with O2 forming free radicals

17
Q

Chain reaction formation?

example?

A

free radicals react with non-radicals causing chain reaction

best example - lipid preoxidation

18
Q

Two steps in Lipid Peroxidation

RH = fatty acid

A
  1. Initation
    RH –> R* + H
2. Propagation/Chain Reaction
(in presence of oxygen)
R* + O2 --> ROO*
ROO* + RH --> ROOH + R*
... cycle continues
19
Q

What builds up from lipid preoxidation?

Problem?

A

ROOH
(fatty acid hydroperoxide)

  • causes oxidative stress
  • disrupts cell membrane, cell damage
20
Q

Micronutrient both anti and oxidative properties

A

iron - react with:

  • ROOH (fatty acid hydroperoxide)
  • H2O2

Produces: OH* (VERY BAD)
ROOH + Fe2+ –> Fe3+ + OH* + RO-

21
Q

Hydroxy Radical (OH*)

A

BAD!!

  • no positive role
  • formed with iron
  • reacts instantly with everything

Problems
- FR chain reaction, mutates DNA, cancer initiation, protein damage

22
Q

Harber-Weiss reaction

Problem?

A

OH* (hydroxyradical) formation

Superoxide (O2*-) + Hydrogen Peroxide (H2O2)

OH* much stronger

23
Q

Vitamin E key structural features

A
  1. OH Groups
    - reactions w oxygen (ROO*)
  2. Ring Structure
    - forms non-reactive free radicalV
24
Q

Vit E reaction

A

Vit E + ROO*

Vit E becomes free radical
ROOH formed still but chain is broke

Ring structure makes it less reactive

  • Vit C donates a hydrogen
  • Vit E back to normal
25
Q

Vit E fatty acid ratio

A

1 Vit E for 400 fatty acids

- not nearly enough to prevent ROOH production

26
Q

What deals with ROOH that Vit E can’t handle?

A

Enzymes

  • Glutathione Peroxidase (needs selenium)
  • Glutathione Reductase (riboflavin, niacin)

*ROOH to harmful compounds

27
Q

Enzymes for superoxide (O2*-)

A

Superoxide Dismutase

  • Zinc and Copper (cytoplasm)
  • Manganese (mitochondrial)

Forms: H2O2
- metabloized by catalase (iron)

28
Q

how is iron bad?

A

ROOH to form OH*
- harter-weiss reaction

possible initiation of lipid peroxidation

29
Q

how is iron good?

A

needed for catalase enzyme to detoxify H2O2

30
Q

Unique about Beta-Carotene?

A

Depends on O2 of partial pressure
Low - anti-oxidant
High - pro-oxident

31
Q

Why are anti-oxidants relevant to CVD?

A

Oxidative damage to LDL greatly enhances development of atherosclerosis
- Oxidized LDL accelerates several steps in atherosclerosis

32
Q

Anti-oxidants that prevents CVD

A 
Vit E (35%)
-inhibits oxidation of LDL

Beta-Carotene (22%)
- decreased cell uptake of oxidized LDL

33
Q

Two studies to know about anti-oxidants

A

ATBC and CARET

- both studies showed an INCREASE lung cancer with B-carotene supplementation

Nutrition 3330 (22 decks)

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