Lecture 11a- 17 November 2014 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

Lecture 11 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 lecture 11 Nutritional Requirements Lipid Minerals Iron Calcium Vitamins Anti-oxidant vitamins and B- carotene 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 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 seconds

Energy production Aerobic pathway If going for continued muscle activity of more than 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 O 2 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