Micronutrients Flashcards
Name and describe the two types of miconutrients
vitamins: organic nutrients which are essential for an organism
cannot be synthesised by that organism
minerals: inorganic nutrients which include trace elements and macrominerals
which twp vitamins can the body synthesise and where are they synthesised from
Vit D: skin
Vit K: gut bacteria
Name the main functions of vitamins and which vitamin helps with each function
1) energy metabolism: B complex helps with coenzymes of the krebs cycle
2) antioxidant: A,C,E
3) synthesis of body componants:
C = collogen
A = bone and visual pigment
K = blood clotting factors
D = bone
what are the daily requirements for minerals and trace elements
macrominerals = > 100 mg/day
trace elements = <20 mg/day
Name the main functions of minerals and give examples of which minerals are involved in this function
structure: e.g constituants of bone and teeth (Ca, P)
fucntion: e.g elecrolytes for maintaining osmolaltity
regulation: e.g iodine in thyroxine
other elements also make up parts of proteins or act as cofactors
Name three common ROS found in the body
Superoxide
Peroxide
Hydroxyl radical
Name some endogenous sources of ROS
aerobic respiration
other biochemical reactions
WBC produce them for phagocytosis
produced by cells when exposed to hypoxia or ionising radiations
Name some external sources of ROS
Air pollution
smoking
UV light
radiation
Name three important antioxidant enzymes
Superoxide dismutase
Catalase
Glutathione Peroxidase
what two vitamins act as antioxidants and what structures do they protect
C (present in aqueous structures)
E (membranes)
How are free radicals involved in muscle fatigue
increased ROS production during muscle contraction
causes oxidative damage to muscle proteins
reduces force production
What effect was shown when infusing subjects with N-acetylcystine before exercise
vs saline infusion = longer time to fatigue with antioxidant
what are the arguments against using antioxidant supplementation in athletes
is little evidence of benefit for antioxidants other than N-acetylcystine
should have adequate amounts if consuming a sufficient diet
evidence that large amounts can be detrimental to performance
no evidence that oxidative stress is harmful to health
exercise training naturally increases enzymatic and non-enzymatic antioxidant production
may impair adaptation bc ROS is possibly a signal to promote expression of skeletal muscle proteins
what are the arguments for using antioxidant supplementation in altheletes
rigorous training = ROS production, supplementation can protect muscle proteins
mostly non-toxic unless taken in v high doses
radicals promote muscle fatigue and N-acetylcystine attenuates fatigue
can be used in case on inadequate dietry intake
give evidence suggesting that vitamin C supplementation may impair adaptation
placebo vs 1 g/day supplement over 8 weeks of endurance training
placebo = 22% increase in VO2 max vs 11% in supplement group
thought to be due to downregulation of expression of transcription factors associated with mitochondrial biogenesis due to supplementation
what conclusions have been drawn from the available data about using supplements in athletes
limited data to support recommending use
need for caution when using high levels of antioxidants
should instead focus on having a well balanced diet
give arguments supporting the use of vitamin D supplements in athletes
Many athletes may be deficient
especially those with pigmented skin, indoor training or training at high latitude
some evidence that it can improve athletic performance in those who are deficient
give arguments against the use of vitamin D in athletes
limited evidence that it is ergogenic
risk of toxicity
large individual variation in response to vitamin D supplementation
from readings, what is the proposed mechanism for why N-acetylcystine supplementation delays fatigue
prevents ROS supression of Na/K ATPase and therefore attenuates plasma increase in K concentration
