Transcript Introduction to Sports Nutrition

Introduction to Sports Nutrition
Chapter 1
Nutrition for Sport and Exercise
Dunford & Doyle
Learning Objectives
 Explain the need for an integrated training and
nutrition plan.
 Explain basic nutrition principles and how they
might be modified to meet the needs of athletes.
 List sports nutrition goals.
 Outline the basic issues related to dietary
supplements and ergogenic aids, such as
legality, ethics, purity, safety, and effectiveness.
Learning Objectives (cont’d)
 Distinguish between types of research studies,
weak and strong research designs, and
correlation and causation.
 Compare and contrast the academic training
and experience necessary to obtain various
exercise and nutrition certifications.
Proper nutrition supports training,
performance, and recovery.
p1
Sports Nutrition
• Definition: A blend of nutrition and exercise
physiology
• Nutrition supports the body’s ability to
respond and adapt to physical challenge
• Sports nutrition is a young field; knowledge
base is continually expanding as
understanding evolves and research is done
• Athlete must use genetics, training, and
nutrition to their advantage in order to
achieve success
Definitions
• Exercise Physiology – Science of the response
and adaptation of bodily systems to the
challenge imposed by movement
• Nutrition – Science of ingestion, digestion,
absorption, metabolism and biochemical
functions of nutrients
• Sports Nutrition – Integration and application of
scientifically based nutrition and exercise
physiology principles that support and enhance
training, performance, and recovery
What is an Athlete?
• A person who participates in a sport
o Elite
o Well-trained
o Recreational
Differences in Types of Athletes
• Elite
– Exceptionally skilled
– Dedicated to training
• Well-trained
– Collegiate athletes
– Dedication to training is important to maintain and
improve performance
• Recreational
– Some are former competitive athletes
– Train very little, if at all
– Primary focus is healthy lifestyle and enjoyment
Defining Physical Activity, Exercise, & Sport
• Physical Activity — bodily movement
resulting in an increase in energy
expenditure above resting levels
– Exercise — physical activity that is planned,
structured, and purposive
– Sport — competitive physical activities
Defining Physical Activity, Exercise, & Sport
• Exercise
– Aerobic — with oxygen
• Uses oxygen-dependent energy system for energy (oxidative
phosphorylation)
• Endurance activities
• “Endurance” or “ultraendurance” athletes
• Examples: Triathlon, Marathon
– Anaerobic — without oxygen
• Uses energy system that is not dependent on oxygen (creatine
phosphate replenishes ATP rapidly, or anaerobic glycolysis)
• Short in duration and high in intensity
• “Strength” or “power” athletes
• Examples: Sprints, Shot Put, Heavy Weight-lifting
Defining Intensity, Training, & CV Fitness
• Intensity – the absolute or relative
difficulty of physical activity or exercise
• Training – a planned program of exercise
with the goal of improving or maintaining
athletic performance
• Cardiovascular fitness – ability to
perform endurance-type activities,
determined by heart’s ability to provide O2rich blood to exercising muscles and ability
of those muscles to take up and use O2
Importance of Training and Nutrition
“Everyone is an athlete; only
some of us are not in training”
-George Sheehan, running philosopher (1980)
Importance of Training and Nutrition
• Sports performance is improved by skill
development and training
– Skill development – practice, instruction,
coaching
– Training – sport-specific
• Physical conditioning – consistent physical training
to improve specific components of fitness
– Ex/ distance runners must have high level of
cardiovascular fitness, which is developed through
rigorous running training program
– More widely used even for athletes such as golfers and
race car drivers
Importance of Training and Nutrition
• Nutrition supports training and good health
• Nutrition for recovery
– Inadequate replenishment of fluid, energy,
carbohydrate, protein and vitamins/minerals
will lead to fatigue during next training
session
• Consistent inadequate replenishment will lead to
chronic fatigue
• Consistent daily proper nutrition plan
important – or can lead to “crash dieting”
or other quick fixes
Training Goals for Athletes
•
•
•
•
Improving performance (main goal!)
Improving specific components of fitness
Avoiding injury and overtraining
Achieving top performance for selected
events (i.e., peaking)
Long-term Nutrition Goals for Athletes
• Adequate energy intake to meet the energy
demands of training
• Adequate replenishment of muscle and liver
glycogen with dietary carbohydrates
• Adequate protein intake for growth and
repair of tissue, particularly muscle
• Adequate overall diet (ex/ proteins,
antioxidant vitamins) to maintain a healthy
immune system
• Adequate hydration
• Appropriate weight and body composition
Short-term Nutrition Goals for Athletes
• Consumption of food and beverages to
delay fatigue during training and competition
• Minimization of dehydration and
hypohydration during exercise
• Use of dietary strategies known to be
beneficial for performance (such as
precompetition meal, caffeine intake, or
carbohydrate loading)
• Intake of nutrients that support recovery
• Appropriate timing of nutrients
Basic Training and Nutrition Principles
•
•
•
•
•
Progressive overload
Individuality
Specificity
Hard/Easy
Periodization
o Macrocycle
o Mesocycle
o Microcycle
• Disuse
1. The principle of progressive overload
• Overload
– An exercise stimulus that is of sufficient
magnitude to cause enough strength to
warrant long-term changes by the body
• The body will adapt to the overload
stimulus
• For further adaptation to occur, the
overload stimulus must be progressively
increased
2. The principle of individuality
• Individuals may respond and adapt
differently when exposed to the same
training stimulus
• Ex/ 2 similar athletes that follow the same
strength training program will both improve
their strength, but amount and rate of
change in strength will be different
• Must take this into account when
designing an athlete’s training program
3. The principle of specificity
• The type of physiological responses and
eventual adaptations will be specific to
the type of stimulus and stress imposed
on the body
• “Specificity” refers to a training program
that stresses muscles in a manner similar
to which they are to perform
• Ex/ Aerobic exercise will result in
cardiovascular adaptations
4. The principle of hard/easy
• Hard physical efforts are followed by
training sessions with less physical stress
to allow for the rest necessary for optimal
adaptation
• Rest and recovery are required for
adaptation to occur
5. The principle of periodization
• Periodization refers to dividing a block of
time into distinct periods
– Macrocycle
• Overall time period beginning at onset of training
and goes up to specific athletic goal
– Mesocycle
• Macrocycles divided into mesocycles of varying
lengths of time, each with specific training purpose
– Microcycle
• Repeated time intervals that make up mesocycle
6. The principle of disuse
• Occurs if stress is insufficient or absent
• Body can adapt negatively
• Atrophy
– Wasting or decrease in organ or tissue size
• Intentional or unintentional
• May occur when an athlete has forced
inactivity due to an injury
• “Use it, or lose it!”
Training and Nutrition Periodization
• Training periodization involves changing
the intensity, volume, and specificity of
training to achieve specific goals
• Nutrition periodization refers to a
nutrition plan developed to support the
various training cycles
– It should match the training plan
– Each mesocycle and microcycle will have
specific nutrition goals
A Training and Nutrition Periodization Plan
Plyometric Exercise
• Definition: Specialized type of athletic
training that involves powerful, explosive
movements
– These movements are preceded by rapid
stretching of these muscles
• Muscles exert maximum force in as short a
time as possible, with the goal of increasing
both speed and power
• “jump training”
• Commonly used in martial arts, high jumping
“10 Best Plyometric Exercises for MMA, Martial
Arts and Combat Fighters”
– Barbell jump squats
– Plyo Push-ups
– Skipping/jumping rope
– Tuck jumps
– Box jumps
– Explosive step-ups
– Lateral hops – one-legged hops
– Med ball wall throws
– Bounding – long jumps
– Depth jumps
Video
• https://www.youtube.com/watch?v=DEjGc
g_I_Cw
Basic Nutrition Standards and Guidelines
• Sports nutrition principles are based on
sound general nutrition principles
o Dietary Reference Intakes (DRI)
o Dietary Guidelines for Americans
o MyPlate (previously MyPyramid)
o Other meal planning systems
• Can be modified to reflect demands of
training and competition
The Dietary Reference Intakes (DRIs) Reference Values Defined
The DRIs
• DRIs were developed for the general
population, but also apply to athletes
– Energy, fluid, Na may be higher for athletes
than general population
• DRI is the current standard
– RDA is one of the reference values of DRIs
• When an RDA cannot be determined, the AI
becomes the reference value for the DRI
• See DRI Tables – inside front cover of text
Dietary Guidelines for Americans, 2010
• Encompass Two Over-Arching Goals:
o Maintain calorie balance over time to achieve
and sustain healthy weight
o Focus on consuming nutrient-dense foods
and beverages
• Key Recommendations
o Balancing Calories to Manage Weight
o Foods and Food Components to Reduce
o Foods and Nutrients to Increase
o Building Healthy Eating Patterns
MyPlate Is a Tool for Creating a
Nutritious Diet
Figure 1-9 p13
Food Pyramid
for Athletes
• Athletes 20-35 yrs old,
• Weighing 50-85 kg,
• Training 5-28 hrs/week
Basic Nutrition Standards and Guidelines
• Others
o Food Exchange System (See Appendix D)
Categorizes foods based on carbohydrate, protein,
and fat content
Based on exchange lists by ADA
Foods can be exchanged with foods that have same
macronutrient composition, but there may be
substantial differences in micronutrient composition
o Carbohydrate Counting
45-60 g CHO/ meal plus 15-20 g CHO/snack
o Dietary Analysis software
Nutrition Facts Label
Basic Sports Nutrition Guidelines
• Athletes need to understand general
nutrition principles and then can “fine tune”
nutritional intake to meet individual
demands of training
Key Sports Nutrition
Recommendations for Athletes
1. Energy
Adequate amount needed to support training
and performance and overall health
Avoid long-term energy deficits or excesses
2. Carbohydrates
3-12 g CHO / kg body weight per day
Depends on sport, type of training, gender,
CHO loading
Timing is important – before, during, and after
Key Sports Nutrition
Recommendations for Athletes
3. Proteins
1.2-1.7 g/kg body weight
Depends on sport, type of training, desire to
increase or maintain skeletal muscle mass
Timing important
4. Fats
20-35% of total calories
5. Vitamins & Minerals
Meet DRI for all vitamins and minerals
Consume “nutrient dense” foods
Key Sports Nutrition
Recommendations for Athletes
6. Fluid
Balance fluid intake with fluid loss
Consider athlete’s sweat rate, humidity,
temperature, altitude
Body water loss of 2-3% of body mass can
decrease performance and negatively affect
health
Hyponatremia can occur if too much water is
ingested and can be potentially fatal
Key Sports Nutrition
Recommendations for Athletes
7. Food and fluid before exercise
Relieve hunger, help with hydration
Volume depends on amount of time prior to
exercise and GI tolerance
In general, a meal or snack should be –
high CHO, moderate protein, low fat
Key Sports Nutrition
Recommendations for Athletes
8. Food and fluid during exercise
Replace fluid lost in sweat and provide CHO
9. Food and fluid after exercise
Replenish nutrients lost during exercise and
help to speed recovery
CHO to replenish muscle glycogen
Protein to repair muscle tissue
Fluid to restore hydration
Electrolytes if large amounts lost in sweat
Some Critical Areas Involving Diet
• Disordered Eating (DE)
– Abnormal eating pattern, but not as severe
as an eating disorder
• Eating Disorder (ED)
– A substantial deviation from normal eating,
which meets established diagnostic criteria
– Ex/ Anorexia Nervosa, Bulimia Nervosa,
Anorexia Athletica
Some Critical Areas Involving Diet
• Adhering to rigid diet can lead to social
isolation and lead to compulsive behavior
• Goal is for flexible eating and to include a
variety of foods
• Flexibility may cause short-term over and
undereating, but results in long-term
weight stability, proper nutrition, and
enjoyment of eating
Dietary Supplements
• Dietary Supplement Health and Education
Act (DSHEA) – law passed in 1994 that
governs dietary supplements in the U.S.
• Supplement is defined as a “vitamin, mineral,
herb, botanical, amino acid, metabolite,
constituent, extract, or a combination of any of
these ingredients” (FDA, 1994)
• The law does NOT ensure or require safety or
effectiveness
• Supplements cannot claim to treat, prevent,
diagnose, or cure a disease
Dietary Supplements
• The law includes standards to ensure that the
supplements:
1. contain the intended ingredients
2. are free from contamination
3. are accurately labeled
• Good Manufacturing Practices (GMP)
– Quality control procedures for the manufacture of
products ingested by humans to ensure quality and
purity
– Intended to bring dietary supplement manufacturing
standards closer in line with pharmaceutical standards
Supplement Use in Athletes
• ~85% of all elite athletes use one or more
dietary supplement (Lun et al, 2012)
• ~70% of adolescent athletes use one or
more dietary supplement
• Collegiate and high school athletes
frequently use supplements
– Energy drinks and calorie replacement drinks
– MVI, Vitamin C
– Creatine
– Protein powders and protein drinks
Why do athletes take supplements?
• Consumption of poor diet
• Physical demand of training & competition
• Teammates and competitors are taking
supplements
• Recommendation by physician, coach or
parent
• To avoid sickness
• Lack of time to prepare meals
• To overcome injury
• To enhance overall health
Legality of Supplements
• Many athletes are governed by the
International Olympic Committee (IOC) or
the National Collegiate Athletic
Association (NCAA)
• Each athlete is responsible for knowing
the current rules as they pertain to dietary
supplements
• Banned substances may be intentionally
or unintentionally added to some
supplements
Safety of Dietary Supplements
• Important to consider ingredients and dose
• Be careful with:
– Caffeine
– Ephedrine (banned)
– DHEA (banned)
– Weight loss supplements and energy drinks
(may contain banned substances)
– Herbal supplements (contamination, lack of
standardization, interactions w/ meds)
Purity of Dietary Supplements
• Purity refers to lack of contamination and
accurate labeling
• Lack of standardization common in herbal
supplements
• Dietary supplement certification programs
– ConsumerLab.com
– NSF
– United States Pharmacopiea
– Informed-Choice
Figure 1-12 p20
Research – Gurley, Gardner, & Hubbard. (2000). Content vs. label claims
in ephedra-containing dietary supplements. American Journal of Health
Systems Pharmacy, 57(10), 963-969.
• Compared amount of ephedra contained
in supplement to amount listed on label
• Results:
– ½ of supplements varied by > 20%
– One contained no ephedra
– One contained 150% of the amount stated on
label
– 5 out of 20 supplements contained
norpseudoephedrine (a controlled/banned
drug)
Effectiveness of Dietary Supplements
• Most dietary supplements sold are NOT
effective for improving performance, increasing
muscle mass, or decreasing body fat
– >30,000 supplements in U.S. – little or no scientific
evidence of effectiveness for majority
• Scientific research has shown safety and
effectiveness at recommended doses for:
–
–
–
–
Caffeine
Creatine
Vitamins & Minerals
Protein
Effectiveness of Dietary Supplements
• Some supplements have shown promise
and are still under investigation:
– Beta-alanine for buffering muscle pH
– Branched-chain amino acids for immune
system support and reduction of post-exercise
fatigue
– Growth hormone releasers, such as arginine,
to stimulate growth hormone release
– Omega-3 fatty acids for asthma
– Quercitin for antiinflammatory effects
“Quackery”
• The practice of making false claims about
health-related products
– This can include dietary supplements
• Often marketed under Multi-Level Marketing (MLM)
• Nonprofit websites devoted to combatting
health misinformation, fraud, and quackery
– National Council Against Health Fraud (NCAHF)
– Quackwatch.org
• Consumers need to do their research!
Process for Evaluating Dietary
Supplements = Critical Thinking Skills
Understanding and Evaluating Scientific
Evidence
• Sports nutrition recommendations should
be evidence-based
o Based on scientific research and evidence to
determine the most effective outcome
o Quality of research is important
o Also, use clinical judgment and evaluate the
athlete’s personal preferences and values
Understanding and Evaluating Scientific
Evidence
• Types of Research Studies:
 Case studies
o Observational records
o Weakest type of study
 Epidemiological studies
o Studies health-related events
in a population
o Shows associations and
correlations
 Experimental studies
o Follow strict protocols and
control most variables
o Establishes cause and effect
relationships
o Strongest type of study
Understanding and Evaluating Scientific
Evidence
• Correlation – a relationship between
variables
• Cause-and-effect – implies that one
causes the other
• Mortality – refers to the number of deaths
in a population
• Placebo – an inactive substance
• Placebo effect – subjects taking placebo
will have a perceived improvement
Understanding and Evaluating Scientific
Evidence
• Research Design and Methods
– Control (Placebo) & Experimental (Treatment)
groups
– Randomization of the sample – and randomly
assigned to placebo or treatment groups
– Placebo – inactive substance
• Double-blind
– Neither the subjects nor the researchers know who is
receiving placebo and who is receiving treatment
– Helps to reduce bias
– Crossover design – subjects receive both
treatments
Research Design – Crossover
Understanding and Evaluating Scientific
Evidence
• The strongest research protocol is a
randomized, double-blind, placebo-controlled,
crossover study performed on humans
• Also, the larger the number of subjects (n) the
stronger
• Should be peer reviewed before publication
– Scrutinized by trained professionals
• Well-designed studies reduce bias and help
ensure accurate results
Figure 1-15 p26
Levels of Evidence and Grades of
Recommendations
• Grade I (Level A)
– Supported by good evidence; consistent
results of well-designed, large, randomized
research studies; confidence high
• Grade II (Level B)
– Supported by fair evidence; less-convincing
results due to inconsistent results or limited
number of well-designed studies, or studies
with weaker designs
Levels of Evidence and Grades of
Recommendations
• Grade III (Level C)
– Supported by limited evidence; confidence
limited by study size and/or design or by size
of body of literature
• Grave IV (Level D)
– Supported by expert opinion (panel
consensus judgment) based upon review of
body of experimental research
• Anecdotal Evidence
– Personal account or testimonial
Levels of Evidence and Grades of
Recommendations
• Scientific research is graded to help
indicate strength and quality
• Ideally – Grade A evidence would be
available to answer all questions regarding
nutrition and training needs for athletes,
however…..
…..sports nutrition is a YOUNG
field and there is not always a lot of good
evidence!
Drawing Appropriate Conclusions from
Scientific Research
• Distinguish between correlation and
causation
• Importance of replicating results
• Extrapolate with caution, if at all
• Interpret results correctly
• Focus on cumulative results and consensus
– general agreement among members of a group
• Recognize slow evolution of knowledge
Is the Research Study Similar to the
Competitive Event?
Consumer Exposure to Scientific Studies
• Widely reported in the media
– Television, magazines, newspaper
• Preliminary data typically reported
• Cause and effect inferred, when its actually
correlation or association
• Results used as marketing tool
• Professional responsibilities include:
– Providing science-based information
– Recognize and correct misinformation
– Address the effects of misinformation
Use of the Internet for Nutrition, Exercise,
and Health Related Information
• Widely used for health information
• Much of this information is inaccurate or poor
quality
– < 25% physical activity websites considered high
quality (Bonnar-Kidd et al, 2009)
• Look for HONcode
– Code of conduct for medical and health websites
– Backs up claims with research
– Clearly distinguishes advertising from editorial
content
Use of the Internet for Finding Scientific
Information about Sports Nutrition
Many Types of Practitioners in Exercise
Science
• Background in…
– Anatomy
– Physiology
– Principles of exercise and fitness
• College degrees in…
– Exercise science
– Kinesiology
– Physical education
– Other related degrees
Scope of Practice and Certifications for
Exercise
• Scope of practice helps to establish
professional boundaries by outlining skills,
responsibilities, and accepted activities
• Scope of practice takes into account
academic training and professional
knowledge and experience
• Scope of practice protects both consumers
and practitioners
• Practitioners must recognize the limitations of
their training, skills, and knowledge
Scope of Practice and Certifications for
Exercise
• American College of Sports Medicine
(ACSM)
– Registered Clinical Exercise Physiologist
(RCEP)
– Clinical Exercise Specialist (CES)
• Bachelors degree in allied field
– Health/Fitness Specialist (HFS)
• Associates or bachelors in allied field
– Certified Personal Trainer (CPT)
• High school diploma
Scope of Practice and Certifications for
Exercise
• National Strength and Conditioning
Association
– Certified Strength and Conditioning Specialist
(CSCS)
• Must have bachelors or chiropractic degree and
CPR certification
• National Athletic Trainers Association
– Certified Athletic Trainer (ATC)
• Must have degree from athletic training program
and pass certification exam
Figure 1-20 p31
Scope of Practice for Sports Nutrition
• Nutrition scope of practice
– Registered Dietitian (RD) or Registered
Dietitian Nutritionist (RDN)
•
•
•
•
•
Bachelor’s degree
Supervised practice or internship
National certification
State licensure
RD/RDN can provide “Medical Nutrition Therapy”
or MNT
– Nutritionist
• General term
• Training can range from marginal to rigorous
Scope of Practice for Sports Nutrition
• Nutrition-related certifications
– Board Certified Specialist in Sports Dietetics
(CSSD)
• RD for >2 years
• 1500 hours in sports nutrition w/in past 5 years
– Certified Sports Nutritionist from the
International Society of Sports (CISSN)
• 4 year degree in any field
– Certified Lifestyle Eating and Performance
Therapist (CLT)
• BS in Nutrition
Figure 1-21 p32
Summary
• The ultimate goal of sports nutrition is
improved performance, which involves
both skill development and training
• Proper nutrition helps to support training,
performance, and recovery
• Sports nutrition principles are based on
sound general nutrition principles that
have been modified to reflect the demands
of training and competition for the athlete’s
sport and position
Summary
• Dietary supplements are widely used by
athletes, but are not well regulated
• Sports nutrition recommendations should
be evidence-based
• Practitioners must understand and respect
the limitations of their training, skills, and
knowledge
• Many people who work with athletes are
certified or licensed