Lecture 5 - Micronutrients Flashcards
What is the role of micronutrients in physical activity?
Many are involved in energy metabolism
-Mg Fe Ca Na K niacin NADH, riboflavin FADH
Who might be more affected by micronutrient deficiency?
While marginal deficiencies may not affect a sedentary person, they may have a more profound effect when metabolic rate is high
-Might not be able to tell if you don’t stress the system and the marginal deficiencies wont present symptoms
○ Stressing thee system will reveal the deficienciees more
What might prolonged strenuous activity performed on a regular basis may result in?
○ Increased losses
○ Increased rates of turnover
Increased intake may compensate for the increased need bit it may not
which athletes are at greater risk of deficiency?
Teenagers, need to support normal health growth and development and the training on top of that.
-Peak bone mass being developed.
which mineral does not have a blood marker?
Ca
-no marker but always stable in blood casue they are pulled from bones to maintain levels
What is the major cause of Fe loss during activity?
Microischaemia is the major cause Microbleeding from the gut
-Excessive sweating and urine contribute little
What is foot srtrikes hemolysis and who does it happen to?
the mechnaical destruciton fo red blood cells in the foot does exist in runners but Fe is salvaged(there is no loss of Fe)
○ Jumping breaks blood cells
What might intensive sports trigger?
• Intensive sport may trigger hepcidin bursts, which leads to blockage of Fe release from gut
What is hepcidin?
Controls Fe entry into body
Where can Fe be stored?
In intestinal cells
What happens when Fe enters the cell?
we take away an e- to hold it theree
What is ferroportin?
Mechanisms to prevent Fe overload cause high Fe is toxic
-controlled by hepcidin because it blocks the entry of Fe into the body. Could be absorbing it so inkate could be good but whether or not it gets into the body is of concer.
What can hepcidin burst look like?
Low Fe intake but in reality they arent
What is the evolution of Fe deficiency?
Ferritin decreased
If declines too low to provide tissues with sufficient Fe, there is an increase in the transferrin receptor
- Hm MCV MCH are still normal
- Nonaneamic Fe deficiency
If continues, RBC become microcytic
MCV and MCH become low
Fe deficiency with microcytosis and or hypocy with microcytosis and othchromia
Hb falls then you have Fe deficiency anaemia
What is the role of Fe in exercise?
Carries O2
Energy metabolism
What is the prevalence of Fe deficiency in adolescents?
20%
What is Fe depletion without anemia?
reduced oxidative capacity (decreased mito)
- Can still inmpact performance eveen if oyua rent anaemic
- Work performance will be stunted
What is the key factor of Fe deficiency anemia?
reduced O2 carrying capacity
What is oxidative stress?
When exercise we produce free radicals by using O2 which isnt completely reduced and forms O2 intermediates or ROS
• During normal metabolism oxygen is utilized in the mito for eneergy profuciton
What is the most dominant source of ROS?
Mitochondria
-Only accounts for 0.15% of total O2 consumption (VO2) turns into ROS
What is the Most vulnerable targets for ROS?
○ Protein lipid DNA
What is exercise induced oxidative stress?
Exercise increases VO2 which translates to a greater O2 uses
○ ROS also depends on intensity
This results in an increase in ROS production
-Increase in ROS depends on workload
What does ROS do?
can elicit damage,
fatigue
can impair recovery
they can also play important roles in skeletal muscle function and metabolism
What is hormesis?
if exposed to something in low dose continually, or high dose occasionally you can have beneficial adaptations that happens.
- Ex: exercise is a continuous low stress
- We don’t want really high continual stress frequently
What is the role of ROS in the body?
Impotant molecular messangers that react with redox ssensitive proteins
-These regulate many physiologucla processes
Which physiological processes does ROS regulate?
○ Insulin sensitivity ○ Vasodilation ○ Mitochondrial biogenesis ○ Immune response ○ Growth factor signalling ○ Force production
Can cells adapt to ROS the more you exercise?
Cells adapt to ROS becoming more resistant to the adverse effects of oxidative stress
Which mechanisms are positively affected by ROS?
○ Increased antioxidant enzymes. DNA repair systems, mitochondria, heat proteins
○ Positively affect muscle remodelling (hypertrophy)
Is antioxidant supplementation detrimental to exercise adaptation?
May reduce the actue exercise antioxidant repsons and impair endurance training iinduced increases in antoiioxidant enzyme levels
What are the results of acute and chronic antioxidant supplementation?
• Acute supplementation before exercise may enhance performance requiring single bout
• Chronic supplementation has no effect on performance and may attenyste improvements due to training
○ Especially tryd for high intensity exercise performance
