Proteins, amino acids Proteins, amino acids and and

exercise exercise

Proteins and amino acidsProteins and amino acids Proteins Proteins

the most important biological compounds the most important biological compounds needed for life   needed for life  

act as the structural materials in humans act as the structural materials in humans Enzymes are proteins that catalyze the body's Enzymes are proteins that catalyze the body's

chemical reactions.  chemical reactions.  make up muscles that aid in movement.  make up muscles that aid in movement.  

Amino acidsAmino acids Proteins are made up of chains of amino Proteins are made up of chains of amino

acids. acids.  an amine group (-NHan amine group (-NH22) bonded to a carbon ) bonded to a carbon

atom that is bonded to a carboxylic acid atom that is bonded to a carboxylic acid group (-COOH)group (-COOH)

Amino acids can bond together by Amino acids can bond together by peptide bondpeptide bond

Amino acids (AA)Amino acids (AA) 20 amino acids in the nature20 amino acids in the nature Classification of amino acidsClassification of amino acids

Essential AAEssential AA - methionine, leucine, isoleucine, lysine, - methionine, leucine, isoleucine, lysine, phenylalanine, threonine, tryptophan, and valinephenylalanine, threonine, tryptophan, and valine

Conditionally essential AA Conditionally essential AA - histidine, arginine (required - histidine, arginine (required for infants)for infants)

Nonesential AA Nonesential AA – glycine, aspartic acid, asparagine, – glycine, aspartic acid, asparagine, proline, glutamine, glutamic acid, cysteine, tyrosine, proline, glutamine, glutamic acid, cysteine, tyrosine, serine, alanine, hydroxyprolineserine, alanine, hydroxyproline

Digestion and absorption of proteinDigestion and absorption of protein

Digestion Digestion The stomachThe stomach

Hydrochloric acid, pepsineHydrochloric acid, pepsine Proteins Proteins =>=> polypetides, amino acids polypetides, amino acids

The small intestineThe small intestine pancreatic and intestinal proteasespancreatic and intestinal proteases

Polypeptide Polypeptide =>=> oligopeptides, tripeptides, dipeptides, amino oligopeptides, tripeptides, dipeptides, amino acidsacids

Peptidase Peptidase Tripeptides and dipeptides Tripeptides and dipeptides =>=> amino acids amino acids

Absorption Absorption Specific carriers transport AASpecific carriers transport AA

Roles of proteins in the body Roles of proteins in the body

As a building materialAs a building material As enzymesAs enzymes As hormonesAs hormones As regulator of fluid As regulator of fluid

balancebalance As acid-base regulatorsAs acid-base regulators As transportersAs transporters As antibodiesAs antibodies As a source of energy As a source of energy

and glucoseand glucose

Protein metabolismProtein metabolism Protein turnover and the amino acid poolProtein turnover and the amino acid pool

proteins are being made and broken downproteins are being made and broken down Nitrogen balanceNitrogen balance

Positive – growing infants, childrens, pregnant womenPositive – growing infants, childrens, pregnant women Negative – people who are starving or suffering severe Negative – people who are starving or suffering severe

stress stress Using AA to make proteins, nonessential AAUsing AA to make proteins, nonessential AA Using AA to make other compoundsUsing AA to make other compounds

Tyrosine Tyrosine → n→ neurotransmitters - norepinephrine, pigment melanin, eurotransmitters - norepinephrine, pigment melanin, hormon thyroxin, precursor for the vitamin niacinhormon thyroxin, precursor for the vitamin niacin

Using AA for energyUsing AA for energy Glucose, fatty acid is limited Glucose, fatty acid is limited =>=> amino acids are amino acids are

source of energy source of energy Deamination AADeamination AA

Broken down AA (source of energy)Broken down AA (source of energy) =>=> stripped of their nitrogen-containing amino stripped of their nitrogen-containing amino

groups (NHgroups (NH22)) ammonia ammonia =>=> urea urea

Using AA to make fatUsing AA to make fat If a person eat a lot of protein If a person eat a lot of protein =>=> convert to fat and convert to fat and

storestore

Proteins in food and their qualityProteins in food and their quality Source of proteinSource of protein

Animal source – meat, fish, milk and dairy products, eggAnimal source – meat, fish, milk and dairy products, egg Plant source – lentils, legumes, nuts, whole grains, vegetablesPlant source – lentils, legumes, nuts, whole grains, vegetables

Limiting AA Limiting AA e.g. lysine in grains, methionine in legumese.g. lysine in grains, methionine in legumes

Complete proteinComplete protein= animal protein – contains all esential AA= animal protein – contains all esential AA

Biological value (BV)Biological value (BV) A measure of protein qualityA measure of protein quality The amount of protein nitrogen that is retained from a given The amount of protein nitrogen that is retained from a given

amount of protein nitrogen absorbedamount of protein nitrogen absorbed BV egg 100, meat 92 – 92, fish 94-96, legumes 75-80, grains 70BV egg 100, meat 92 – 92, fish 94-96, legumes 75-80, grains 70

RDA of protein RDA of protein 12 – 15 % energy12 – 15 % energy Diet 2000 kcal = 300 kcal from protein = 75 gDiet 2000 kcal = 300 kcal from protein = 75 g

Age Age Protein RDA (g/kg)Protein RDA (g/kg)

11- 14 11- 14 1,01,0

15 - 1815 - 18 0,8 – 0,90,8 – 0,9

AdultAdult 0,80,8

Endurance athlete Endurance athlete 1,2 -1,41,2 -1,4

Strength athlete Strength athlete 1,4 – 1,81,4 – 1,8

Children athlete Children athlete 1,51,5

Approximate protein content of various foodsApproximate protein content of various foods FoodFood Protein (g)Protein (g)

Beef 3 ozBeef 3 oz 2828

Pork 3 ozPork 3 oz 2828

Cod 3 ozCod 3 oz 2121

Oysters 3 ozOysters 3 oz 1717

Milk 1 cMilk 1 c 88

Cheddar cheese1 ozCheddar cheese1 oz 77

Egg 1 largeEgg 1 large 66

Peanut butter (1 tbs)Peanut butter (1 tbs) 88

Po1 medtato 1Po1 medtato 1 33

Bread 1 sliceBread 1 slice 22

Banana Banana 11

Carrots 2 cCarrots 2 c 11

Apple 1Apple 1 22

Sugar, oil Sugar, oil 00

Metabolism of amino acids and Metabolism of amino acids and protein during exercise protein during exercise

Amino acid x not source of energyAmino acid x not source of energy

Hormones influence muscle protein turnoverHormones influence muscle protein turnover Influence synthesis, breakdown or bothInfluence synthesis, breakdown or both

Anabolic - synthesisAnabolic - synthesis Catabolic – breakdownCatabolic – breakdown

Single exercise bout modify the amount of Single exercise bout modify the amount of circulating levels of hormonescirculating levels of hormones

Growth hormone, tyrosin Growth hormone, tyrosin ↑↑

Hormones influence muscle protein Hormones influence muscle protein turnover turnover

InsulinInsulin Release is stimulated by elevated blod glucose and Release is stimulated by elevated blod glucose and

less potently by elevation of AAless potently by elevation of AA Promote uptake of AA to cells (skeletal muscle)Promote uptake of AA to cells (skeletal muscle) Promote a synthesis of protein, limiting break Promote a synthesis of protein, limiting break

downdown During exercise is release of insulin blunted During exercise is release of insulin blunted

(greater glycogen and fat breakdown)(greater glycogen and fat breakdown) Endurance exercise - more AA available for Endurance exercise - more AA available for

gluconeogenesis gluconeogenesis

Hormones influence muscle protein Hormones influence muscle protein turnoverturnover

Cortisol Cortisol Released by the adrenal gland during physiological or Released by the adrenal gland during physiological or

nutritional stressnutritional stress Stress hormoneStress hormone Increase energy nutrient availaility – breakdown proteinIncrease energy nutrient availaility – breakdown protein Vary in level during exercise (intensity, duration)Vary in level during exercise (intensity, duration)

Growth hormone (GH)Growth hormone (GH) Increase during exercise, remain elevated for some time Increase during exercise, remain elevated for some time

afterwardafterward Increase level of AA after protein rich meal Increase level of AA after protein rich meal =>=> ↑ GH ↑ GH ↑ ↑ GH GH =>=> ↑ AA uptake to muscle cells, protein synthesis ↑ AA uptake to muscle cells, protein synthesis

Hormones influence muscle protein Hormones influence muscle protein turnoverturnover

Insuline-like growth factor 1 (IGF-1)Insuline-like growth factor 1 (IGF-1) Anabolic efect of GH is mediated with IGF-1Anabolic efect of GH is mediated with IGF-1

If IGF-1 is If IGF-1 is ↓ and GH is ↑ = inhibited protein synthesis↓ and GH is ↑ = inhibited protein synthesis

TestosteroneTestosterone Promoter of protein synthesis in musclePromoter of protein synthesis in muscle Enhance utilization of AA for protein synthesisEnhance utilization of AA for protein synthesis Level of testosterone Level of testosterone ↑ = resistance and endurance ↑ = resistance and endurance

trainingtraining

Resistance exercise (RE)Resistance exercise (RE) Protein synthesisProtein synthesis

unchanged or reduced during REunchanged or reduced during RE Increase for several hours after REIncrease for several hours after RE

Protein breakdownProtein breakdown Not occur during RENot occur during RE May increase after REMay increase after RE

AA oxidationAA oxidation Not enhanced during RENot enhanced during RE

Consumption of a carbohydrate and protein meal after RE Consumption of a carbohydrate and protein meal after RE =>=> minimize protein breakdown minimize protein breakdown

=>=> maximize protein synthesis maximize protein synthesis

Endurance exercise (EE)Endurance exercise (EE) Protein synthesisProtein synthesis

unchanged or reduced during EEunchanged or reduced during EE Protein breakdownProtein breakdown

can occur during higher intensity, longer duration EEcan occur during higher intensity, longer duration EE AA oxidationAA oxidation

Can occur during prolonged moderate to higher intensity Can occur during prolonged moderate to higher intensity submaximal EEsubmaximal EE

Consumption of carbohydrate and protein meal after Consumption of carbohydrate and protein meal after EEEE

=>=> minimize protein breakdown minimize protein breakdown =>=> maximize protein synthesis maximize protein synthesis

Protein intake of athletesProtein intake of athletes Endurance athlete Endurance athlete 1,2 - 1,4 g/kg1,2 - 1,4 g/kg Strength athlete Strength athlete 1,4 – 1,8 g/kg1,4 – 1,8 g/kg

Timing and composition of meal - Timing and composition of meal - postexercisepostexercise Carbohydrates – fuel and increase the uptake of AACarbohydrates – fuel and increase the uptake of AA AA – allows for an influx into muscle cells, protein synthesisAA – allows for an influx into muscle cells, protein synthesis

After trainingAfter training 0,5 g protein per kg + 1,5 g carbohydrates per kg 0,5 g protein per kg + 1,5 g carbohydrates per kg Weight training - at lest 135 g of carb. and 45 g of protein for a 90 kg weight Weight training - at lest 135 g of carb. and 45 g of protein for a 90 kg weight

trainer trainer Endurance training – at least 105 g of carb. and 35 g of protein for a 73 kg Endurance training – at least 105 g of carb. and 35 g of protein for a 73 kg

endurance athlete endurance athlete = 560 – 720 kcal (1/5 – 1/6 daily energy = 560 – 720 kcal (1/5 – 1/6 daily energy

needs)needs) After 3-4hour eat againAfter 3-4hour eat again

=>=> Maximise positive efect of exercise on muscle protein turnoverMaximise positive efect of exercise on muscle protein turnover

Protein intake of athletesProtein intake of athletes

Timing and composition of meal – Timing and composition of meal – during exerciseduring exercise Carbohydrate consumption (e.g. Sport drinks) – support better recovery Carbohydrate consumption (e.g. Sport drinks) – support better recovery

and adaptation and adaptation

Number of mealsNumber of meals Numerous smaller meals over the waking hoursNumerous smaller meals over the waking hours

= more consistent influence on insulin level = more consistent influence on insulin level

= minimize catabolic periods between meals= minimize catabolic periods between meals

= more consistent availability essential AA = more desirable = more consistent availability essential AA = more desirable influence on protein synthesisinfluence on protein synthesis

5 – 6 meal during a day 5 – 6 meal during a day After exercise approximately 40 g proteinAfter exercise approximately 40 g protein Each other meal 15 – 20 g of proteinEach other meal 15 – 20 g of protein