Micronutrients Flashcards
List the two broad micronutrient types
Vitamins and Minerals
Briefly describe Vitamins
Organic micronutrients
Cannot be syntheiszed, obtained from diet
Briefly describe Minerals
Inorganic micronutrients
Trace elements & Macrominerals
List two Vitamins that can be synthesized
D: in skin from cholesterol w exposure to UV
K: by gut bacteria
How are Vitamins classified, list some in each category
Water soluble: B, C
Fat soluble: D, A, K, E
What are three main functions of Vitamins?
Energy Metabolism
Antioxidants
Synthesis of Body Components
List Vitamin responsible for: Energy Metabolism
B complex
List Vitamin responsible for: Antioxidants
A, C, E
List VitaminS responsible for: Body component synthesis
C: Collagen, hormones (norepinephrine)
D, A: Bone
K: Bone clotting factors
A: Visual pigment
What are the two subcategories of minerals? How are they categorized?
Based on body requirements
Minerals: >100mg / day
Trace elements: <20mg / day
List the elements that are Minerals
Ca, P,
Mg, K,
Fe, Na,
Zn, Cl
List elements that are Trace elements
Cr, Cu,
Fl, I
Mn, Mb
Se
Describe broadly main functions of Minerals
- Structure (constituents bone & teeth)
- Function (body fluid osmolality, ICF EFC volume; heart rhythm, muscle contratibility, neural conductivity)
- Regulation (components of hormones and enzymes)
Minerals responsible for Structure?
Ca, P, Mg: bone and teeth
Minerals responsible for function?
Electrolytes (Na, K, Cl, Mg, Ca): soluble salts responsible for body fluid osmolality ICF & EFC volume
Minerals responsible for Regulation?
I: component of thyroxine (hormone)
Fe, Cu, Zn, Se: components of enzymes/cofactors
Describe what are Antioxidants & Free Radicals
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)
What are 4 ways Free Radicals are produced endogenously?
- Intermediates in normal biochemical reactions
- White blood cells produce ROS > kill pathogens
- Cells exposed to abnormal environments
- Ionizing radiation
Describe the Antioxidant system and how it works
Enzyme & Non-Enzyme antioxidant systems
Removes unpaired electron from free radical
Antioxidant then regenerated
Give 4 examples of Enzyme antioxidant systems
Superoxide dismutase
Catalase
Glutathione peroxidase
Gluthathione reductase
Give 3 examples of Non-Enzyme antioxidant systems
Vitamin E (protects membranes from oxidative dmg) Vitamin C (aqueous components of body) Flavonoids, Carotenoids
Describe what happens in the control of radicals for Non-Enzyme systems
Neutralising free radical > Vitamin E becomes a radical (loss of antioxidant capacity)
Vitamin C can regenerate Vitamin E at lipid-water abrrier
What is relation between Antioxidants and Muscle Fatigue
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
Describe relationship between Antioxidants & Performance
McKenna 2006
Time to fatigue at 92% VO2 Max prolonged with N-acetylcysteine infusion
Arguments for supplementation (Antioxidants)?
Rigorous training > increased ROS
Radicals show to promote fatigue in muscle
Inadequate dietary intake
Arguments against supplementation (Antioxidants)?
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
Evidence for impaired skeletal muscle adaptation?
VO2 max increased less in Vitamin C supplemented group
Reduced transcription factors assoc with mitochondrial biogenesis
General recommendations for antioxidant supplementation?
Should not use AO supplements
Well-balanced, energetically adequate diet rich in AO-containing foods
