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Lecture 11a- 16 March 2016
This lecture is based largely on CHAPTER 23 IN
KRAUSE'S FOOD NUTRITION AND DIET
THERAPY (ON RESERVE IN LIBRARY) AND
CHAPTERS 7,8,9 IN ROLFES ET AL.
Final exam-120 multiple choice-120 marks
from vitamins to end of course
-4 short answer questions-15 points
each for a total of 60 points
covers whole course
-3 hours- 180 marks
Lectures 11ab
Outline
Metabolic aspects of Nutrition and fitness/Sports Nutrition
Energy production
ATP
Anaerobic pathway
Aerobic pathway
Energy continuum
Sources of fuel
Outline of lectures 11ab
Energy production
Substrate choice
Intensity
Duration
Effect of training
Diet
Outline of lectures 11ab
Nutritional Requirements
Fluid
Fluid Balance
Fluid Absorption
Factors affecting fluid absorption
Requirements
Short duration
Endurance
Outline of lectures 11ab
Nutritional Requirements
Carbohydrate
Types of carbohydrate
Pre-event
During event
Post-event
Outline of lectures 11ab
Nutritional Requirements
Protein
Endurance
Resistance Exercise
Amino acid supplementation
Outline of lectures 11ab
Nutritional Requirements
Lipid
Minerals
Iron
Calcium
Vitamins
Anti-oxidant vitamins and Bcarotene
C
E
B vitamins
Outline of lectures 11ab
Regulation of metabolism
More Detailed Comments
Energy production
Aerobic and anaerobic both provide ATP but
which system predominates depends on oxygen
supply to the tissues
Energy production
ATP
Energy currency of the cell
ATP to ADP plus Pi
-done by ATPase
Creatine phosphate is split to creatine and
phosphate
-this provides the energy to
resynthesise ATP via creatine
kinase
Energy production
ATP
limited amount of creatine phosphate in the
body so this is a very limited way to replace
ATP- creatine phosphate process is anaerobic
if all-out exercise -this process can only go
on for 5-8 seconds- eg power lifting
Energy production
Anaerobic pathway
No oxygen
Glycolysis is the quickest way to make ATP
Lactic acid is endproduct (enzyme
implications)
Two hydrogens transferred to pyruvate
thus making lactate- This results in
the freeing of NAD to participate
further in making ATP-but relatively
small amount of ATP synthesis
Energy production
Anaerobic pathway
Lactic acid is rapidly removed from the muscle
and transported in the blood and is eventually
converted to energy in the muscle, liver or
brain OR it is converted to glycogen
Conversion to glycogen occurs largely in the
liver and to some extent in the muscle
Lactic acid buildup in the blood leads to drop
in pH resulting in enzymatic activity drops
which in turn results in fatigue
Energy production
Anaerobic pathway
Oxygen debt-recovery oxygen consumptionthe difference between oxygen consumption in
the post-exercise recovery phase and the
oxygen consumption at rest
Fuel source is limited to glucose and produces
a relatively small amount of ATP relative to
aerobic metabolism
All out effort for 60-120 seconds
Energy production
Aerobic pathway
If going for continued muscle activity of more
than 90-120 seconds one needs oxygen
Energy is stored in high-energy phosphate
bonds in ATP through a complex series of
enzymatically guided reactions involving
separation of hydrogen atoms from the parent
compounds
Energy production
Aerobic pathway
Vital to this process is the presence of
coenzymes which act as hydrogen acceptors
until the process of oxidative phosphorylation
results in the formation of ATP
Ultimately hydrogen combines with O2 to
form water and the coenzymes are freed to
accept more hydrogen so as to continue the
process
Energy production
Aerobic pathway
Glucose is broken down much more
efficiently than is the case with
anaerobic glycolysis
In the presence of oxygen, pyruvate is
converted to Acetyl CoA
Acetyl CoA enters the mitochondria and is
then introduced into the Kreb’s cycle
Energy production
Aerobic pathway
Proteins and lipids can also be metabolized to
produce ATP
Lipids- the beta oxidation of lipids produces a
large amount of ATP
Proteins can be catabolised to Acetyl CoA or
to Kreb’s cycle intermediates and in this way
produce ATP
Break