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Transcript of PEMAKANAN & KECERGASAN › uploads › 6 › 0 › 3 › 6 › 60367799 › ... · 2018-09-01 ·...
12/8/2011
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PEMAKANAN & KECERGASAN
Denise Koh
What is Nutrition?
• The science of food, the nutrients and the
substances therein, their action, interaction,
and balance in relation to health and disease,
and the process by which the organism
ingests, absorbs, transport, utilizes, and
excretes food substance.
Nutrition & Fitness
• A field of study that is concern with the study
of foods and their effect on the human body.
• The central focus of nutrition is the study of
food requirements for the production of
energy and the regulation of bodily processes.
Nutrition & Disease
• 6 out of 10 leading causes of death are chronic
diseases.
• Prevention is the best approach to lessening
one’s chances of getting these diseases
• Physical activity and diet are 2 of the leading
lifestyle factors in the prevention.
YOU ARE WHAT YOU EAT
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Status of Nutritional Health
• Desirable
• Undernutrition
– Depleted nutrient storage
– Reduced biochemical function
– Clinical signs and symptoms
• Overnutrition
– Excess intake of calories and fat
– Obesity
– Use of vitamins and mineral supplements
What is Nutrient?
• A nutrient is a basic substance that is used by the body to sustain vital processes such as repair and regulation of cellular functions and the production of energy.
• 6 classes of nutrients:– Carbohydrates (glucose)
– Fats (2 fatty acids)
– Proteins (9 Amino Acids)
– Vitamins (13 vitamins)
– Minerals (21 minerals)
– water
General Function of Nutrients in Food
• Provide water
• Provide fuel for entire body
• Provide building blocks
• Provide metabolic regulators
General Function of Nutrients in Food
• Carbo, proteins & Fat – give energy and maintenance of body tissue.
• Vitamins and minerals has no calorie count.
– Vitamins have critical role in releasing energy from food.
– Mineral essential to regulation and performance of body function such as maintenance of water balance.
• Water most essential of all nutrients!
Water
• Water is most basic of all nutrients- necessary
to sustain life.
• 60% of body weight
• Essential for both functions as energy
production, digestion, temperature regulation,
and elimination of the by-product of
metabolisme.
Water and Exercise
• Maintaining water balance is very important.
Severe dehydration can cause death.
• Particularly important among people who
exercise, and especially important to those
who exercise in hot and humid weather.
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A Calorie
• A measurement of energy measured in a
bomb calorimeter.
• “the amount of heat it takes to raise the
temperature of 1 gram of water by 1 degree
celsius”
• Food is measure in kilocalories (kcal)
• Calories with a large “C” on nutrition label are
in kcal.
The Energy Nutrient
• Carbohydrates (1g carbohydrates = 4 calories)
– 65-75% of caloies
– Complex vs simple
• Protein (1h protein = 4 calories)
– 20% of kcal
– Unsaturated vs saturated
• Fat (1 g fat = 9 calories)
– 10-15% of kcal
Diet and Health
• A well-balanced diet is important to obtain all
required nutrients for the body.
Ergogenic Aid - Defined
• Substance or device that enhances energy
production, use, or recovery and provides an
athlete with a competitive advantage.
Ergogenic Aid - Examples
• MechanicalMechanicalMechanicalMechanical (shoes)
• PsychologicalPsychologicalPsychologicalPsychological (hypnosis)
• PhysiologicPhysiologicPhysiologicPhysiologic (blood doping)
• NutritionalNutritionalNutritionalNutritional (creatine)
• PharmacologicPharmacologicPharmacologicPharmacologic (anabolic steroids)
Why do athletes use supplements?
• Provide more convenient form of nutrient
• Prevent a perceived deficiency
• Provide direct ergogenic effect
• Belief that every top athlete is taking it; they
can’t afford to lag behind
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Many athletes will do whatever it takes to win…
• In 1995, 198 Olympic-level
power athletes were given
this scenario:
– You are offered a banned
substance with 2
guarantees:
• You will not be caught
• By taking the substance you
will win
Only 3 declined!Only 3 declined!Only 3 declined!Only 3 declined!
• The same 198 athletes were
offered a banned substance
with 2 additional guarantees:
– You will win every event for the
next 5 years
– You will die at the end of those
5 years
50% still said they would use it!50% still said they would use it!50% still said they would use it!50% still said they would use it!
…at any cost
1996-1999 10,449 boys and girls age
12-18 surveyed:
– 4.7% of boys and 1.6% of girls used
protein powder or shake, creatine, amino
acids/HMB, DHEA, growth hormone, or
anabolic steroids at least weekly to
improve appearance or strength
PrevalencePlacebo effect in athletes
• Athletes are HIGHLY
suggestible
– 97% believe placebo
effect works
– 73% said they had
experienced it
– Beedie CJ. J Sports Sci
Med 2007
• “Expectancy Effect” is
significant
– Belief in efficacy �
performance
improvement
• Pill Colors
red/orange/yellow �
stimulant
• Injection > pill
• Expensive > cheap
StimulantsCaffiene
• Is a stimulant found in a variety of foods.
• The IOC classifies it as a restricted drug,
allowing its use up to a certain level.
• Standard is up to a urine level of 12
micrograms/mililiters = 6-8 cups of coffee.
• Absorbed rapidly and shows up in blood
within 15 minites.
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Caffeine’s Proven Effects
– Increased time to fatigue (”capacity”) in wide
range of lab protocols
• Prolonged submaximal (> 90 min)
• Sustained high-intensity (20-60 min)
• Short-duration supra-max (1-5 min)
– Likely beneficial in endurance and “stop-n-go”
sports
– No clear benefit in strength/power events
Caffeine in Endurance Running
• 4.2-sec faster 1.5-km
• 1-3% faster 5-km
• 24-sec faster 8-km
• 50-sec faster 10-km military pack march
• No change in 21-km race
• Improved treadmill time-to-exhaustion in
marathoners
Caffeine in Other Sports
• Rowing: 1-3% faster 2000m
race
• Swimming: 24-sec faster
1500m race
– About 21 min
• Cycling: 3.5% higher mean
power in 40km race
Caffeine Dosing
• Doses 2-9 mg/kg in studies• 2-5 mg/kg usually effective
• 250-500 mg
– Cola: 40 mg
– Coffee: 100 mg
– Tea: 20-100 mg
– Red Bull: 115 mg
– Vivarin: 200 mg
• No difference in fx between “users” and “non-users”
Caffeinated Sports Drinks
• No proven performance benefit
– 18-km run times
– Pl vs carb drink vs carb+150mg
caffeine
– consumed 4x in race
– Int J Sports Med 2005
Effects of Caffeine
• Ergogenic effects varies.
• Effects more pronounced among athletes
whom do not regularly consume caffeine.
• Athletes who abstained from caffeine for a
period of days prior to its use also have more
pronounced effects.
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Side effects of caffeine
• Very rapid heart rate
• Diuresis
• Insomnia
• Nervousness
• Diarrhea
• anxiety
Carbohydrate Loading
• Glycogen stored in the liver and active muscle
supplies most of the energy for intense
aerobic exercise.
• As the exercise period gets longer, glycogen
stores become diminish and fat metabolisme
becomes larger contributor to energy
production.
• This leads to fatigue
Carbohydrate Loading
• Physiologists have known for a long time that
a high carbohydrate diet is beneficial to
endurance performance.
Carbo Loading
• Research has shown that a particular
combination of exercise and diet can “pack”
the muscle with glycogen above normal level.
• The procedure is known as carbohydrate
loading
Approach to carbo loading 1
• Classical approach:
– Athletes begin the process of carbo loading 7 days
prior to competition. Athletes deplete glycogen
stores by training till exhaustion. Hard trainig
x4days, rest x3days.
– Also modify diet: first day = 50% carbo; next 3
days = high fat & protein. Next 3 days, 90% carbo.
– On day of comp: have high carbo meal.
Approach to carbo Loading 2
• 5 days before competition
– Decrease workout time by 90 minutes to 40
minutes, while eating 50% carbo.
– After 2 days, reduce workout time from 4o
minutes to 20 minutes, while eating 70% carbo.
– Day of competition, rest and eat 70% carbo.
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Carbo Loading
• Eat 1-5g of carbo /kg weight prior to event
• Eat 1-4g of carbo /kg weight prior to exercise.
• The meal should be easily digestable
• If taken 1 hour before event, then it should be
in liquid form.
Hydration, Energy and Sport Drink
• Exercise – sweat – depleting water in body
• Recommends:
– 4-6 ounces of water for every 15-20 minutes of
exercise
• Fluid replacement:
– Reduce heart rate
– Body temperature
– Athletes perception of fatigue
Creatine
• Most popular nutritional
supplement
• In 2000, >$300 million in sales
in the US
• Replenishes ATP in
anaerobic exercise
– Made in liver, kidneys,
and pancreas
– Dietary sources: meat,
fish
– Stored in skeletal muscle
– Excreted as creatinine in
urine
Creatine
Creatine – disproven effects
• Meta-analysis 2002:
– NO overall benefit on anaerobic performance (weight lifting, sprint cycling, spring running, sprint swimming, kayaking, arm cranking, or jumping/kicking)
– 29 quality studies
• 35% were statistically significant between Cr and Placebo
• 65% NON statistically significant
Creatine – disproven effects
• Meta-analysis 2003:
– No significant difference in field-based athletic
performance (e.g. running, swimming)
Branch JD. Int J Sports Nutr Exerc Metab June 2003
X X XX X XX X
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Creatine – proven
effects
• 2003 meta-analysis of strength efx:
– 8% increase in 1RM strength vs placebo (20% vs 12%)
– 14% increase in # of reps
– Highly variable response
• Body Composition
– Increase in weight and lean body mass by 1-2 kg over
short term
Rawson, Volek. J Strength Cond Res 2003.
• Increases PCr energy availability
– ->Increased effort in resistance training
Creatine Mechanisms of Action
• Increased satellite cell and myonuclei • Increased gene expression for contractile
proteins
– Due to more available energy
• Increased contractile protein synthesis
Creatine Mechanisms of ActionCreatine Mechanisms of Action Creatine - Side Effects
• Studies of 2-10 weeks: no side efx
• Long term:
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Creatine - regulation
• Not banned anywhere
• Surveys suggest ~ 50% of male college
athletes and 1/3 of all NFL players are on
creatine
Anabolic Steroids
• Analogs of testosterone
• More than 100 types
• Forms:– Oral
– Injection
– Topical (gels, creams)
• Prevalence 2009– Jr high: 2%
– 12th grade: 5% (males 7%, >females 2%)
Anabolic Steroids – Proven Effects
• Increase in fat-free mass
• Increase in body weight
• Increase in arm girth
• Increase in leg girth
• Increase in bench press and
squat scores
• Increase in libido
Anabolic Steroids—Disproven Effects
• No effect on endurance exercise
– Males on treadmill
• Eur J Appl Physiol 2006
– VO2max in rats
• Med Sci Sports Exer 2004
Anabolic Steroids - Side Effects
• Hepatocellular
damage
• Cardiovascular
disease (stroke, MI)
• Psychological
disturbance
Effects can sometimes
be permanent!
“Side effects of anabolic androgenic
steroids abuse”Followed body builders for 2 years
• Decr sperm count and fertility index
• Decr HDL (57 � 42)
• No change liver/prostate US, hematological
indices
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More side effects…
MenMen
–– AcneAcne
–– Premature baldnessPremature baldness
–– Prostatic hypertrophyProstatic hypertrophy
–– ProstatitisProstatitis
–– *Injection complications*Injection complications
–– Testicular atrophyTesticular atrophy
–– *Impotence*Impotence
–– **GynecomastiaGynecomastia
• Adolescents
– Premature closure of physes –
stunted growth
– Decreased libido
– Depression
More side effects…
WomenWomen
–– Clitoral enlargementClitoral enlargement
–– Menstrual dysfunctionMenstrual dysfunction
–– MaleMale--pattern baldnesspattern baldness
–– **MasculinizationMasculinization
–– Deepening of voiceDeepening of voice
–– **HirsutismHirsutism
More side effects…Side effects that can be PERMANENT
• Premature growth plate closure
• Testicular atrophy
• Gynecomastia
• Male pattern baldness
• Female masculinization
• Excessive hair growth
• Deepening voice
• Clitoral enlargement
Anabolic Steroid regulation
• Illegal except by
prescription
• Banned by most
international sports body