9 Antioxidants and Micronutrients

Question 1

Fruits and Vege consumption known for decrease rates of?

Answer 1

Cancer and Disease

Question 2

What attributes to fruit and vegetables nutritional benefit?

Answer 2

antioxidants

Question 3

Micronutrients (essential) antioxidants

Answer 3

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

(work together as co-enzymes)

Question 4

Why do we need Antioxidants

Answer 4

• Balance between Pro/Anti

- Oppose oxygen toxic effects

Question 5

Purposes of oxygen

Answer 5

> 95% energy production

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

Question 6

Oxidative stress

Answer 6

Imbalance

• increase ROS production
• decrease antioxidant intake

Severe
- Cell Damage

Question 7

Whats considered cell damage?

Caused by?

Answer 7

Cellular mutations
Tissue Breakdown
Immune Compromise

• caused by oxidative stress

Question 8

Formation of free radicals

Answer 8

oxidative metabolism

Question 9

What are free radicals

Answer 9

molecules with one or more UNPAIRED electrons

- very unstable, highly reactive

Question 10

How to make free radicals stable?

Answer 10

Antioxidants steal electron from another to be stable

Question 11

How do atoms bind?

- why does this make free radicals so bad?

Answer 11

Sharing of electrons

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

Question 12

3 types of free radicals

Answer 12

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

Question 13

Are free radicals normal?

Answer 13

Yes - normal product of cellular reactions

- have useful biological function

Question 14

Types of ROS

Answer 14

Free Radicals

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

Unstable Molecules

• Hydrogen Peroxide (H2O2)
• Ozone (O3)

Question 15

Useful functions of ROS

Answer 15

(produced by phagocytes)

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

Question 16

Accidental production of ROS generation

Answer 16

Electron Transport Chain

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

Question 17

Chain reaction formation?

example?

Answer 17

free radicals react with non-radicals causing chain reaction

best example - lipid preoxidation

Question 18

Two steps in Lipid Peroxidation

RH = fatty acid

Answer 18

1. Initation
   RH –> R* + H

2. Propagation/Chain Reaction
(in presence of oxygen)
R* + O2 --> ROO*
ROO* + RH --> ROOH + R*
... cycle continues

Question 19

What builds up from lipid preoxidation?

Problem?

Answer 19

ROOH
(fatty acid hydroperoxide)

• causes oxidative stress
• disrupts cell membrane, cell damage

Question 20

Micronutrient both anti and oxidative properties

Answer 20

iron - react with:

• ROOH (fatty acid hydroperoxide)
• H2O2

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

Question 21

Hydroxy Radical (OH*)

Answer 21

BAD!!

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

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

Question 22

Harber-Weiss reaction

Problem?

Answer 22

OH* (hydroxyradical) formation

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

OH* much stronger

Question 23

Vitamin E key structural features

Answer 23

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

Question 24

Vit E reaction

Answer 24

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

Question 25

Vit E fatty acid ratio

Answer 25

1 Vit E for 400 fatty acids | - not nearly enough to prevent ROOH production

Question 26

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

Answer 26

Enzymes - Glutathione Peroxidase (needs selenium) - Glutathione Reductase (riboflavin, niacin) *ROOH to harmful compounds

Question 27

Enzymes for superoxide (O2*-)

Answer 27

Superoxide Dismutase - Zinc and Copper (cytoplasm) - Manganese (mitochondrial) Forms: H2O2 - metabloized by catalase (iron)

Question 28

how is iron bad?

Answer 28

ROOH to form OH* - harter-weiss reaction possible initiation of lipid peroxidation

Question 29

how is iron good?

Answer 29

needed for catalase enzyme to detoxify H2O2

Question 30

Unique about Beta-Carotene?

Answer 30

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

Question 31

Why are anti-oxidants relevant to CVD?

Answer 31

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

Question 32

Anti-oxidants that prevents CVD

Answer 32

``` Vit E (35%) -inhibits oxidation of LDL ``` Beta-Carotene (22%) - decreased cell uptake of oxidized LDL

Question 33

Two studies to know about anti-oxidants

Answer 33

ATBC and CARET | - both studies showed an INCREASE lung cancer with B-carotene supplementation