Integration

1
Chapter 7

• Integration Regulation of Metabolism the
  Impact of Exercise Sport

2
Interrelationship of Carbohydrate, Lipid,
Protein Metabolism

• Any energy nutrient can fuel the body in the
  short term
• TCA cycle amphibolic pathway
• Lipogenesis
• CHO spares lipolysis - promotes gain
• Glucose is precursor for glycerol fatty acids

3
Interrelationship of Carbohydrate, Lipid,
Protein Metabolism

• Gluconeogenesis
• Glycerol portion only from fat
• Fatty acids with odd of C atoms
• Glucogenic amino acids
• Conversion among energy nutrients favors
  lipogenesis

4
Interrelationship of Carbohydrate, Lipid,
Protein Metabolism

• TCA cycle electron transport chain - common to
  all 3
• This catabolic pathway also
• Produces CO2 for carboxylation C for other
  needs
• Provides common intermediates
• Provides citrate malate for lipogenesis

5
The Central Role of the Liver in Metabolism

• Key processor distributor
• Glycogenesis glycogenolysis
• Protein synthesis, catabolism, conversion to
  other compounds
• Lipoprotein synthesis

6
Tissue-Specific Metabolism during the Fed-Fast
Cycle

• Stages of fed-fast cycle
• Fed state - lasts 3 hours after meal ingestion
• Postabsorptive/early fasting state - 3 to 12-18
  hours after meal
• Fasting state - 18 hours to 2 days after meal
  when nothing else eaten
• Starvation/long-term fast - fully adapted to
  deprivation (weeks)

7
Carbohydrate Lipid Metabolism

• The fed state
• Glucose ? glycogen fatty acids
• Glucose used by nervous tissues, RBCs, adipose
  muscle tissues
• The postabsorptive or early fasting state
• Glycogenolysis
• Gluconeogenesis

8
Carbohydrate Lipid Metabolism

• The fasting state
• Amino acids (primarily), glycerol, lactate used
  for gluconeogenesis
• Ketone formation
• The starvation state
• Fatty acids used to greater extent
• Glycerol major glucose source
• Ketosis after oxaloacetate depletion

9
Amino Acid Metabolism

• Fed state - used for proteins or degraded
• Fasting
• Catabolism for energy produces quantities of N
• Excreted in urea
• Gluconeogensis in liver kidneys

10
System Integration Homeostasis

• Major regulatory systems
• Nervous system
• Endocrine system
• Vascular system
• Endocrine function in fed state
• GIP, CCK, gastrin, secretin
• Insulin

11
System Integration Homeostasis

• Endocrine function in postabsorptive or fasting
  state
• Glucagon
• Epinephrine norepinephrine
• Low levels of insulin

12
Metabolic Syndrome

• Cluster of risk factors for CVD, CKD T2DM
• Insulin resistance
• Weight loss insulin insensitivity

13
Sports Nutrition

• Energy for physical activity comes from nutrients
• Energy demands during physical exertion in
  athletes similar to fed-fast cycle

14
Biochemical Assessment of Physical Exertion

• Types of muscle
• Type I (red) - oxidative
• Type IIa (white) - hybrid of I IIb
• Type IIb (white) - fewer mitochondria active
  glycolytic pathway
• Common measurements
• Respiratory quotient (RQ)
• Maximal oxygen consumption (VO2 max)

15
Energy Sources during Exercise

• The ATP-CP (phosphagen) system
• Muscles use high-energy creatine phosphate with
  ATP
• The lactic acid system
• Anaerobic glycolysis
• The aerobic system
• TCA cycle

16
Energy Sources during Exercise

• Fuel sources during exercise
• Muscle glycogen
• Plasma glucose
• Plasma fatty acids
• Intramuscular triacylglycerols

17
Energy Sources during Exercise

• Exercise intensity duration
• Low intensity - plasma fatty acids
• Moderate intensity - increased fatty acid
  oxidation (due to muscle TG)
• High intensity - CHO oxidation lactate
  production increase

18
Energy Sources during Exercise

• Level of exercise training
• Training increases muscle glycogen TG stores
• Initial muscle glycogen levels

19
Carbohydrate Supplementation (Supercompensation)

• Classical regimen
• 2 sessions of intense exercise, 2 days of low-CHO
  diet, 3 days of high-CHO diet rest
• Modified regimen
• Exercise tapered over 5 days, 1 day of rest
• 3 days of 50-CHO diet, then 3 days of 70-CHO
  diet

20
Diets for Exercise

• Macronutrients
• Meal frequency
• Pre-event meal
• Glycemic index

21
Nutritional Ergogenic Aids

• Amino acids
• Arginine
• Ornithine
• Aspartate salts
• Branched-chain amino acids
• Antioxidants

22
Nutritional Ergogenic Aids

• Herbs
• The ginsengs
• Caffeine
• Intermediary metabolites
• Bicarbonate
• Carnitine
• Coenzyme Q10
• Creatine
• Other

23
Perspective 7

• Diabetes Metabolism Out of Control

24
Diabetes

• Type 2 diabetes
• Insulin resistance in peripheral tissues due to
  lack of functional glucose transporters
• Type 1 diabetes
• Lack of insulin due to autoimmune response
  against pancreatic ?-cells