Lecture 11a- 28 March 2019

2. Lecture 11a- 28 March 2019 This lecture is based largely onCHAPTER 23 IN KRAUSE'S FOOD NUTRITION AND DIET THERAPY (ON RESERVE IN LIBRARY) AND CHAPTERS 7,8,9 IN ROLFES ET AL.

3. 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

4. Lectures 11ab Outline Metabolic aspects of Nutrition and fitness/Sports Nutrition Energy production ATP             Anaerobic pathway             Aerobic pathway             Energy continuum             Sources of fuel

5. Outline of lectures 11ab Energy production Substrate choice Intensity Duration Effect of training Diet

6. Outline of lectures 11ab Nutritional Requirements             Fluid                  Fluid Balance                  Fluid Absorption Factors affecting fluid absorption                  Requirements                          Short duration                          Endurance

7. Outline of lectures 11ab Nutritional Requirements            Carbohydrate Types of carbohydrate                         Pre-event                         During event                         Post-event

8. Outline of lectures 11ab Nutritional Requirements            Protein Endurance                 Resistance Exercise Amino acid supplementation

9. Outline of lectures 11ab Nutritional Requirements             Lipid             Minerals   Iron                         Calcium             Vitamins Anti-oxidant vitamins and B-carotene C                         E                         B vitamins

10. Outline of lectures 11ab Regulation of metabolism

11. More Detailed Comments Energy production Aerobic and anaerobic both provide ATP but which system predominates depends on oxygen supply to the tissues

12. 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

13. 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 onfor 5-8 seconds- eg power lifting

14. 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

15. 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

16. Energy production Anaerobic pathway Oxygen debt-recovery oxygen consumption- the 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

17. 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

18. 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

19. 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

20. 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

21. Break