Sport Nutrition second half Flashcards
Define micro-nutrients
Essential nutrients (can’t synth all that we need), required in small amounts for health
Difference between vitamins and minerals
Organic micronutrients essential for a specific organism
Cannot be synth so must be obtained from the diet
Minerals
Essential inorganic micronutrients
Which vitmains can be synthesised by the body?
D can be synth in skin from cholesterol with exposure to UV
Vitamin K synthesised by some gut bacteria
Water soluble vitamins?
B complex (12 different vitmaines C
Fat soluble vitmamins?
A (found in lliver, known as retinoids)
E,D,K
Functions of vitamins
Energy metab
B complex - lots of citric acid cycle components, part of NAD and B5 CoA? Antioxidants A,C,E Synthesis of body components
Collagen Vit C Hormones Vit C (norepinephrine) Bone Vit D, A Blood clotting factors Vit K Visual pigment Vit A
How many minerals, classification?
15 inorganic elements Minerals - required in amounts >100mg.day Ca, P, Mg, K, Fe, Na, Zn, Cl Trace Elements - required in <20mg.day (others)
Function of minerals?
Structure
Bone and teeth
Most abundant - Ca, P, Mg
Function
Soluble salts responsible for body fluid osmolality and determination of ICF and ECF volume
Na, K (more ICF), Cl, Mg, Ca
Maintain normal heart rhythm, muscle contractibility, neural conductivity
Regulation
Components of proteins (hormones and enzymes)
I and thryroxine
Fe, Cu, Zn components of enzymes/ cofactors
What do antioxidants do?
Prevent of limit damaging effects of free radicals in the body (intra and intercellularly)
Atoms or molecules with 1 or more unpaired electron
Most common are reactive oxygen species (ROS)
How are ROS formed?
Aerobic resp - intermediates in normal reactions WBCs-ROS for invading pathogens Hypoxia e.g. HIIT Radiation and pollution Smoking UV Inflammation
Describe enzyme control of radicals e.g. O2-
SOD (o2 -> H2O2)
Catalase (h2O2 = H2O and O2)
Gluathione peroxidase
Describe non-enzyme control of radicals
Non enzyme
Vit E - major lipid soluble antioxidant
Protects membranes from oxidative damage
Vit C
Aqueous components of body
Flavonoids and carotenoids
Role of antioxidants in skeletal muscle fatigue?
Antioxidants in skeletal muscle fatigue
=Inability of muscle to generate force
Radical production may play a role
ROS increases in contracting skeletal muscle
Excessive ROS induces oxidative damage to muscle proteins and reduces force production
Mostly from animal studies - antioxidants protect skeletal muscle from damage and delay fatigue during prolonged submax exercise
No effect on high intensity
Study that an antioxidant can prolong fatigue?
Exercise can be prolonged with N-acetylcysteine infusion (NAC) - antioxidant
70% VO2 max at 45 min then fatigue at 92% VO2max - time increases by miunutes
Little evidence that dietary antioxidants could make a difference e,g, E, C, betacarotene
Arguments for Vitamin C/E supplementation?
Most common are not toxic so no harm
Radicals promote fatigue in skeletal msucel
NAX attenuates
Inadequate dietary intake e.g. Restriction, poor diet, increased training
Arguments against vitamin supplementation?
Exercise oxidative stress -no evidence it harms health
Exercise increases antiocidants (both kinds) in skeletal muscle)
If dietary intake sufficient, supplementation likely not needed
Might impair adaptation of muscle to exercise
ROS signal to promote expression of skeletal muscle proteins
Antioxidant enzymes, mitochondiral proteins and heat shock proteins
Explain the Golman dilemma
198 US olympic athletes asked 2 questions
Would they take performance enhancing drugs if,
Guarenteed to win every comp for 5 years
Guaranteed notto get caught
98% yes
Would they take performance enhancing frugs if:
Same
But guarenteed death from side effects
52% said yes
1992
Findings from the Gooldman dilema revisited?
Athletes more concerned about legality than death
What is Maughan’s rule for supplements
If it works, its banned
If it doesnt work, its not banned
Few exceptions
Why do athletes supplement?
Aid recovery Health Improve performance Prevent. Treat illness. Compensate poor diet Most high level take 80-90% track and field
Why may an athlete have a poor diet and need supplements?
If eliminated food group e.g. Vegan
If put into energy deficit - may need supplements
Need extra valories/ carbs
Why is taking lots of supps potentially detrimental?
Risk of contamination increases
Potential detriment to performance
describe types of nutritional supplements
Ergogenic Ergo=work Genic=making Creatine - from meat, veges better Beta-alanine/carnosine - only is turkey (eat lots for sufficient amount) Biocarbonate Caffeine? - some from foods Nitrate? - some foods e.g. beetroot Sports food Protein Carb - tablets, drinks
which group may benefit from creatine supps the most?
Females
In 2008 how many sipplements contained WADA banned steroids or prohormones?
14.8%