Micronutrients

Question 1

List the two broad micronutrient types

Answer 1

Vitamins and Minerals

Question 2

Briefly describe Vitamins

Answer 2

Organic micronutrients

Cannot be syntheiszed, obtained from diet

Question 3

Briefly describe Minerals

Answer 3

Inorganic micronutrients

Trace elements & Macrominerals

Question 4

List two Vitamins that can be synthesized

Answer 4

D: in skin from cholesterol w exposure to UV
K: by gut bacteria

Question 5

How are Vitamins classified, list some in each category

Answer 5

Water soluble: B, C

Fat soluble: D, A, K, E

Question 6

What are three main functions of Vitamins?

Answer 6

Energy Metabolism
Antioxidants
Synthesis of Body Components

Question 7

List Vitamin responsible for: Energy Metabolism

Answer 7

B complex

Question 8

List Vitamin responsible for: Antioxidants

Answer 8

A, C, E

Question 9

List VitaminS responsible for: Body component synthesis

Answer 9

C: Collagen, hormones (norepinephrine)
D, A: Bone
K: Bone clotting factors
A: Visual pigment

Question 10

What are the two subcategories of minerals? How are they categorized?

Answer 10

Based on body requirements
Minerals: >100mg / day
Trace elements: <20mg / day

Question 11

List the elements that are Minerals

Answer 11

Ca, P,
Mg, K,
Fe, Na,
Zn, Cl

Question 12

List elements that are Trace elements

Answer 12

Cr, Cu,
Fl, I
Mn, Mb
Se

Question 13

Describe broadly main functions of Minerals

Answer 13

1. Structure (constituents bone & teeth)
2. Function (body fluid osmolality, ICF EFC volume; heart rhythm, muscle contratibility, neural conductivity)
3. Regulation (components of hormones and enzymes)

Question 14

Minerals responsible for Structure?

Answer 14

Ca, P, Mg: bone and teeth

Question 15

Minerals responsible for function?

Answer 15

Electrolytes (Na, K, Cl, Mg, Ca): soluble salts responsible for body fluid osmolality ICF & EFC volume

Question 16

Minerals responsible for Regulation?

Answer 16

I: component of thyroxine (hormone)

Fe, Cu, Zn, Se: components of enzymes/cofactors

Question 17

Describe what are Antioxidants & Free Radicals

Answer 17

Antioxidants: prevent/limit damaging effects of free radicals in body
Free Radicals: atoms/molecules w 1 or more unpaired electron (e.g. Reactive Oxygen Species ROS)

Question 18

What are 4 ways Free Radicals are produced endogenously?

Answer 18

1. Intermediates in normal biochemical reactions
2. White blood cells produce ROS > kill pathogens
3. Cells exposed to abnormal environments
4. Ionizing radiation

Question 19

Describe the Antioxidant system and how it works

Answer 19

Enzyme & Non-Enzyme antioxidant systems
Removes unpaired electron from free radical
Antioxidant then regenerated

Question 20

Give 4 examples of Enzyme antioxidant systems

Answer 20

Superoxide dismutase
Catalase
Glutathione peroxidase
Gluthathione reductase

Question 21

Give 3 examples of Non-Enzyme antioxidant systems

Answer 21

Vitamin E (protects membranes from oxidative dmg)
Vitamin C (aqueous components of body)
Flavonoids, Carotenoids

Question 22

Describe what happens in the control of radicals for Non-Enzyme systems

Answer 22

Neutralising free radical > Vitamin E becomes a radical (loss of antioxidant capacity)
Vitamin C can regenerate Vitamin E at lipid-water abrrier

Question 23

What is relation between Antioxidants and Muscle Fatigue

Answer 23

Contracting skeletal muscle > ROS production increase
Excessive ROS > oxidative dmg to muscle proteins & reduce force production
Antioxidants > protect skeletal muscle from dmg & delay fatigue (submaximal) NO EFFECT DURING HIT

Question 24

Describe relationship between Antioxidants & Performance

Answer 24

McKenna 2006

Time to fatigue at 92% VO2 Max prolonged with N-acetylcysteine infusion

Question 25

Arguments for supplementation (Antioxidants)?

Answer 25

Rigorous training > increased ROS
Radicals show to promote fatigue in muscle
Inadequate dietary intake

Question 26

Arguments against supplementation (Antioxidants)?

Answer 26

Dietary intake sufficient, supplementation likely not required
Possible skeletal muscle adaptation impairments (ROS signals to promote expression of skeletal muscle proteins)
Exercise increases enzymatic/non-enz antioxidants in skeletal muscle

Question 27

Evidence for impaired skeletal muscle adaptation?

Answer 27

VO2 max increased less in Vitamin C supplemented group

Reduced transcription factors assoc with mitochondrial biogenesis

Question 28

General recommendations for antioxidant supplementation?

Answer 28

Should not use AO supplements

Well-balanced, energetically adequate diet rich in AO-containing foods