PROTEINSAmino acids linked by peptide chains for proteinsThe body requires 20 different amino acids• alanine, arginine, asparagine aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, prol ine, serine, threonine, tryptophan, tyrosine, valine
Complete vs Incomplete ProteinsComplete - Contain the essential amino acids in the right ratio to maintain nitrogen balance and allow tissue growth & repair.Incomplete - Lacks one or more essential amino acid
Roles of Protein1. Protein in nervous and connective tissues do not participate in energy metabolism2. Amino acid alanine Plays a key role in providing CHO fuel via gluconeogenesis during prolonged exercise3. During strenuous exercise of long duration, alanine - glucose cycle accounts for 40 - 50% of livers glucose release.
PROTEIN UTILIZATION • Protein utilization depends on how well the total energy expenditure is met by the intake of food • Inadequate total energy intake forces the athlete to burn protein • This depletes muscle protein which is not desirable • Protein requirement is about 20% of total calorie intake OR 1.2 to 1.7g/kg body weight
a) PROTEIN REQUIREMENT FORENDURANCE AND RESISTANCE EXERCISE
Protein Requirement for EnduranceExerciseEndurance training might need about 1.2 to 1.6 g x kg(-1) x day(- 1) (approximately 1.5 times the current RDA)Serious endurance athletes need protein above the normal adult RDA for:• maintenance Of LEAN MUSCLE• growth• repair• optimum immune system function
Not providing sufficientprotein will lead to lethargy,anaemia and will cancelbeneficial effects ofexercise. In fed individuals protein is meant to contribute 1-8% to the energy expended depending on the sex and the duration of the athletic competition.
• Protein is used in prolonged, continuous, moderate to intense activity (endurance)• 5-10% of the energy needs for endurance exercise (>90 minutes) may come from protein.• Protein synthesis is suppressed during exercise and stimulated when physical activity ends.• Endurance exercise appears to improve the efficiency of the body to utilize nitrogen.• Amino acids are used to repair muscle trauma that results from repeated muscle contractions and eccentric contractions in particular.
Protein Requirement for Strength ExerciseThose involved in strength training might need to consume as much as 1.6 to 1.7 g protein x kg(-1) x day(-1) (approximately twice the current RDA)Extra protein is needed by strength-trained athletes to repair injuries to muscle fibers and to remodel muscle tissue in response to strength training.
• High intensity, intermittent activity that incorporates strength training in the exercise program.• Resistance exercise provides the stimulus for gains in muscle size and strength.• Strength training relies on anaerobic metabolism for energy production. The primary fuel for resistance exercise is muscle glycogen.• Building muscle is energy intensive.
PROTEIN TURNOVER• Protein turnover (synthesis and degradation) is elevated in strength athletes.• Protein requirements are increased to supply amino acids to maintain nitrogen balance and to support enhanced rates of protein synthesis.• Protein turnover depends on the following factors1. Exercise intensity2. Exercise duration3. Training state4. Energy consumed5. Gender
Exercise IntensityExercise intensity affects the protein turnover directly, based on theexample shown above.
Exercise DurationDuring long duration of exercise there is more break down of proteinresulting in the increase of by products of amino acid oxidation.
... to put this in perspective For example, a person who cycles for 60 minutes in a glycogen depleted state might use as much as 2.4 times the amount of protein as those with high initial glycogen levels.
Training State: • Protein turnover with endurance exercise. • Protein turnover when there is sufficient energy from glycogen. Protein-sparing action of carbohydrateWhen there is an adequate intake of carbohydrate, the body does not need to metabolize muscle protein for energy.Ensuring the energy requirement is met by carbohydrate is vital to preserve the protein in the body
BCAA AND FATIGUEBranched chain amino acids - Leucine, isoleucine, valineSerotonin plays a role in the central mechanisms of fatigueSerotonin is produced from tryptophanTryptophan is usually found in the blood bound to albumin or as free tryptophanThe amount of free tryptophan that crosses the blood brain barrier depends on the concentration of BCAA.
Mechanism - BCAA and FatigueDuring long duration exercise fat is broken down to produce energy as a result of which fatty acids are formed.These fatty acids bind to albumin thus reducing the number of albumin binding sites for tryptophan.At the same time exercise leads to the breakdown of BCAA which causes an imbalance in the tryptophan:BCAA ratio.An increase in this ratio causes the free tryptophan to cross the blood brain barrier and INCREASES the amount of SEROTONIN leading to FATIGUE
What does 100 grams of protein look like in food? Food Amount Protein (grams) Raisin bran cereal 2 cups 10 1% milk 2 cups 16 Bread 2 slices 5 Chicken breast 1 large 19 piece Swiss cheese 1 ounce 8 Lean steak 1 34 Baked potatoes 1 med 5 Broccoli 1 cup 6 Egg white 1 3.6
PROTEIN SUPPLEMENTATIONMany use protein supplements believing that they enhance performance by way of increasing the production of anabolic hormones.Some research shows that there is no significant effect of amino acid supplements on the1. Hormone secretion2. Training response3. Exercise performanceHowever, this is a debatable topic and pros and cons will be discussed.
Whey ProteinWhey protein is the protein contained in whey, the watery portion of milk that separates from the curds when making cheese.Whey protein is used for improving athletic performance, as a food supplement, as an alternative to milk for people with lactose intolerance, for replacing or supplementing milk-based infant formulas, and for reversing weight loss and increasing glutathione (GSH) in people with HIV disease. Contraindication: Uses: Whey taken in regulated In conjunction with strenght quantities does not have any training whey improves: known side effects. 1. Lean muscle mass If taken in excess can lead to: 2. Strength 3. Muscle size 1. Nausea 2. cramps 3. Fatigue 4. Reduced appetite
CaseinCasein is the main protein in milk. It is the ingredient in milk that solidifies when milk curdles. When people drink milk, digestive juices break down the casein into protein pieces called casein peptides Side-effects: Benefits: 1. Rashes 1. Improved muscle Mass 2. Bloating, 2. Great Muscle retention 3. Hives 3. Greater fat loss 4. Stomach aches 4. Helps increase energy and cramps 5. Improves stamina 5. Gastro-intestinal discomfort
L- carnitine CONS:PROS: Some research shows :1. Acts as a vasodilator inperipheral tissues 1. No ergogenic effect2. May enhance regional blood 2. Does nto increaseflow & oxygen delivery anabolic processes3. Improves oxygen supply to 3. No improvement indamaged tissue - May improve performanceDOMS - delayed onset musclesoreness 4. No enhanced recovery
Creatine Benefits: Creatine Risks: Not many risks have been documented after creatine supplementation. Short term use in healthy men has had no detrimental effect on blood pressure and renal function. Individuals with poor kidney function should refrain from taking this supplement.
Activity:Interpret the following graph with regards to Total Creatine.
DiscussionYour thoughts on the use of protein supplements