Transcript FN3373, Lecture 1 (OWL) – Ch 1 (Introduction)

chapter
chapter
11
Introduction to
Nutrition for
Introduction
Exercise andto
Nutrition
Health for
Exercise and
Prof Jennifer Broxterman, RD, MSc
Health
FN3373: Nutrition for Physical Activity
Lecture 1
Author name here for Edited books
Sports Nutrition Introduction
• Proper nutrition can help:
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Improve exercise performance
Decrease recovery time from strenuous exercise
Prevent exercise-associated injuries due to fatigue
Provide the fuel required during times of highintensity training
– Control weight
– Help reduce the risk of numerous chronic diseases
• T2DM, CVD, hypertension, obesity, osteoporosis, some
cancers
Role of Nutrition in
Exercise and Sport
Role of Nutrition in Exercise & Sport
• Nutrition plays a vital role in exercise
performance and training
– Benefits both competitive and recreational athletes
• Good nutrition is especially important for
athletes who:
– Compete in sports tournaments
– Engage in strenuous PA on a daily or more than
daily basis
• Examples?
Injury Reduction
• Risk of injury during exercise
– Fuel & hydration status impacts level of fatigue and
ability to concentrate
• Risk of injury post-exercise
– Proper nutrition can help speed the healing process
for injured athletes
– Surgery / Bone Injuries: requires extra kcal &
nutrients, including protein, vitamins, and minerals
Weight Control / Body Composition
• Nutrition plays an important role in weight
control and body composition
– Few individuals are happy with their weight, body fat
levels, or body shape
– Realistic expectations can improve health and
quality of life and reduce stress levels
– Disordered eating tendencies tend to be
higher in athletes than the general population,
esp. women
Essential Nutrients &
Dietary Recommendations
Essential vs. Nonessential Nutrients
• Discovery
– Evolved from observations that certain diseases
occurred in populations that consumed poor diets
– Able to show that including specific foods in the diet
could correct or prevent the diseases
• Essential nutrients: food constituents that prevent
disease or health problems (“indispensible”)
• Nonessential nutrients: nutrients that could be
deleted from the diet with no adverse health effects
(“dispensable”)
– E.g. physiologically essential nutrient for the body but classified
as a nonessential nutrient?
Conditionally Essential Nutrients
• Conditionally essential: some “essential”
nutrients are synthesized by the body from precursors,
and interactions between nutrients could alter
requirements
• Potentially affected by:
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Some disease states
Genetic defects
Stress
Illness
Aging
Conditionally Essential Nutrients
• Criteria to establish the conditional essentiality
of a nutrient:
1. The plasma concentration of the nutrient declines into
the subnormal range, although the body should be
able to synthesize the nutrient.
2. Chemical, structural, or functional abnormalities
appear that are associated with low blood
concentrations of the nutrient.
3. Dietary supplementation of the nutrient returns plasma
concentrations to normal and corrects the
abnormalities seen when blood concentrations are low.
Desirable & Beneficial Nutrients
• Nonessential nutrients that are important
for good health and disease prevention
– New nutrient category: “desirable or beneficial for
health” (Carpenter and Harper, 2006)
– Examples: fibre, phytochemicals,
carotenoids, amino acid derivatives
– Are NOT classified as essential or
conditionally essential nutrients
Recommended Dietary
Allowances &
Dietary Reference Intakes
Dietary Reference Intake (DRIs)
DRIs
EAR
RDA
AI
UL
Nutrition Recommendations
• Yardsticks used as standards for measuring
healthy people’s energy and nutrient intakes
• Used to:
– Assess nutrient intakes
– Make recommendations on amounts to consume
• Standards in the Canada and U.S. are the Dietary
Reference Intakes (DRI)
– Estimated Average Requirements (EAR)
– Recommended Dietary Allowances (RDA)
– Adequate Intakes (AI)
– Tolerable Upper Intake Levels (UL)
Figure 1.2
Goals of the DRI Committee
1. Setting Recommended Intake Values (RDA, AI)
1. Facilitating Nutrition Research and Policy (EAR)
2. Establishing Safety Guidelines (UL)
3. Preventing Chronic Disease
Goal 1:
Setting Recommended Intake Values
• RDA: based on solid experimental evidence and
reliable observation
– nutrient intake goals for individuals
– derived from EAR
– meets requirement of 97-98% of individuals in a life
stage and gender group
• AI: also as scientifically based as possible, but setting
them requires some educated guesses
– established whenever scientific evidence is
insufficient to generate an RDA
Goal 2:
Facilitating Nutrition Research & Policy
• EAR: nutrient requirements for given life stages and
gender groups that researchers and nutrition
policymakers use in their work
– Public health officials may also use them to assess
nutrient intakes of populations and make
recommendations
– EAR values form the scientific basis upon which the
RDA values are set
Establishment of DRIs
Goal 3:
Establishing Safety Guidelines
• UL
– Identify potentially hazardous levels of nutrient
intake
– Useful to consumers who take supplements or
consume foods or beverages to which vitamins or
minerals have been added
– Public health officials rely on UL values to set safe
upper limits for nutrients added to our food and
water supply
The Naive View vs. Accurate View
of Optimal Nutrient Intakes
Goal 3:
Establishing Safety Guidelines
• People’s tolerances for high doses vary
– Caution is in order when nutrient intakes approach
UL values
• Some nutrients do not have UL values
– Does not imply that it is safe to consume it in any
amount
– Only means that insufficient data exists to establish
a value
Goal 4:
Preventing Chronic Disease
• The DRI committee takes into account
chronic disease prevention, wherever
appropriate
– healthy ranges of intake for carbohydrate, fat, and
protein
• Acceptable Macronutrient Distribution
Ranges (AMDR)
–45%-65% from carbohydrate
–20%-35% from fat
–10%-35% from protein
Understanding the DRIs
• Government funded
• Based on recent scientific research whenever
possible
• Optimal intakes NOT minimal requirements
– Generous margin of safety
– Meet needs of virtually all healthy people within a specific
gender and age group
• Based on specific indicators of nutrient adequacy
– Normal growth and development
– Optimal blood nutrient concentrations
– Reduction of certain chronic diseases and disorders
Understanding the DRIs
• Daily intakes to be achieved on average, over time
– Assume intakes will vary from day-to-day
– Set high enough to ensure that nutrient body stores will meet
nutrient needs (from 1 day to 3 months based on the nutrient)
• Apply to healthy persons only
– Health maintenance and disease prevention
– Not restoration of health
• Separate recommendations gender, age, lifecycle
– Differences between men, women, pregnant and breastfeeding
women, children and other life stage groups
RDA vs. Energy Requirements
Setting Energy Requirements
• Estimated Energy Requirements (EER)
– The average dietary energy intake predicted to
maintain energy balance in a healthy adult of a certain
age, gender, weight, and level of physical activity with
consistent good health
– Value is not generous
– Is set at the average of the population’s estimated
energy requirements
– Enough food energy is critical to support health and life
– Too much energy causes unhealthy weight gain
• The DRI committee did not set a UL for energy
Dietary Guidelines
for Canadians
Eating Well with CFG (2007)
• To help people achieve
goals set forth by Canada’s
Guidelines to Healthy
Eating, Health Canada
provides a food group plan
– Diet planning tool
– Sorts foods into groups
based on their nutrient
content
– Specifies that people should
eat a minimum # of servings
of foods from each group
Vegetables & Fruit
Grain Products
Milk & Alternatives
Meat & Alternatives
Variations of Food Guides
• Many countries have their own nutrition
organizations that develop dietary
guidelines, reference intakes, and food
guide pyramids, rainbows, circles, etc.
– Goal is to meet the dietary needs of the particular
population
– Must consider:
• cultural aspects related to food
• eating patterns
• lifestyle factors
United States: My Pyramid
Mediterranean Food Guide Pyramid
Mediterranean Diet for Athletes
• Endurance athletes
– Marathon & ultra-endurance athletes
– Higher fat diet (~40%)
– Replacement of intra-muscular fat used as a fuel source
during exercise
– Best food sources: nuts, seeds, olive oil, fish
• Athletes with lower energy requirements
– Offers a nutrient-dense diet
– Reduce total fat from olive oil, cheese, & nuts but
maintain high intake of V&F, whole grains, lean protein
Food Pyramid for Athletes
• Swiss Forum for Sport Nutrition
– Builds on the Basic Food Pyramid used in Switzerland,
designed for the normally active
– Covers the extra energy and nutrient requirements
incurred by the demands of daily exercise training
– Carefully considered the volume and intensity of
various sports
– Feasibility of consuming the extra servings for each
food group was also considered for athletes in “real-life”
settings
– Sport-specific foods, fluids, and recovery products were
also integrated
Figure 1.6
Figure 1.6 (continued)
Sweets
Oils/Fats
Protein
Grains
V&F
Fluids
Canadian Physical
Activity Guidelines
Canadian Physical Activity Guidelines
(NEW in 2011)
• Canadian Society for Exercise Physiology
www.csep.ca/guidelines
Children (5-11 y)
Youth (12-17 y)
Adults (18-64 y)
Older Adults (65 y and older)
• New guidelines should be viewed as a minimal target
• Evidence-based, realistic and achievable
• To promote healthy active living for the Canadian
population
– Levels of PA & fitness have dropped dramatically
– Overweight/obesity in Canadian has been steadily
increasing
– Steady rise in diseases associated with overweight &
obesity
Children (5-11 y) & Youth (12-17 y)
GUIDELINES
• For health benefits, children aged 5-11 and
youth aged 12-17 years should accumulate at
least 60 minutes of moderate-to-vigorousintensity PA daily. This should include:
– Vigorous-intensity activities at least 3 days per week
– Activities that strengthen muscle and bone at least 3
day per week
• More daily PA provides greater health benefits
Adults (18-64 y)
GUIDELINES
• To achieve health benefits, adults aged 18-64
years should accumulate at least 150 minutes
of moderate-to-vigorous-intensity aerobic
PA per week, in bouts of 10 minutes or more
• Beneficial to add muscle and bone
strengthening activities using major muscle
groups, at least 2 days/week
• More PA provides greater health benefits
Older Adults (65+ y)
GUIDELINES
• To achieve health benefits and improve functional
abilities, adults aged 65 years and older should
accumulate at least 150 minutes of moderate-tovigorous-intensity aerobic PA per week, in bouts of 10
minutes or more
• Muscle and bone strengthening activities using major
muscle groups at least 2 days/week
• Those with poor mobility should perform PA to enhance
balance and prevent falls
• More PA provides greater health benefits.
Rationale for New PA Guidelines
• Explosion of new research in recent years
• Old guidelines were out-of-date
• Evidence to support more specific
recommendations
• Some age ranges missing with old guidelines
• More robust guideline development processes
now
• Inactivity crisis deserves up-to-date guidelines
Canadian Sedentary Behaviour
Guidelines for Children & Youth
The scientific evidence showed that:
• Being sedentary for more than 2 hours per
day was associated with:
– Unfavourable body composition
– Decreased fitness
– Lowered scores for self esteem and pro-social
behaviour
– Decreased academic achievement
Canadian Sedentary Behaviour
Guidelines for Children & Youth
GUIDELINES
For health benefits, children (aged 5-11 y) &
youth (aged 12-17 y) should minimize the time
they spend being sedentary each day. This
may be achieved by:
– Limiting recreational screen time to no more than 2
hours per day; lower levels are associated with
additional health benefits
– Limiting sedentary (motorized) transport, extended
sitting and time spent indoors throughout the day
For Next Lecture
• Textbook Readings
– Chapter 1: Introduction to Nutrition for Health & Exercise
Get Ahead for Lectures 2, 3, & 4
– Chapter 2: Carbohydrate as a Fuel for Exercise
– Chapter 3: Fat as a Fuel for Exercise
– Chapter 4: Protein and Exercise
• Case Study Project
– Self-select your group of 2-3 people. Topic will be
assigned next class.