Nutrition for Sports, Physical Activity and obesity prevention: Nutrition for Sports, Physical Activity and obesity prevention Bonnie A. Spear, Ph.D., RD
Associate Professor of Pediatrics
University of Alabama at Birmingham
Fluids and Hydration: Fluids and Hydration Younger Teens are at higher risk for heat illness because…. : Younger Teens are at higher risk for heat illness because…. lower sweating rate
higher body surface area
produce more heat with exercise
Dehydration Affects Performance: Dehydration Affects Performance 1% Increased body temperature
3% Impaired performance
5% GI problems, heat exhaustion
10% Circulatory collapse Responses to Dehydration: Responses to Dehydration INCREASE IN:
Muscle glycogen use
Temperature at which sweating begins and blood flow increases
Renal blood flow
Central blood volume
Endurance capacity Fluid losses increased with: Fluid losses increased with Caffeine ingestions
Rehydration Guidelines: Rehydration Guidelines Water vs. Sports Drinks: Water vs. Sports Drinks Research on active kids showed they'll drink 90% more of Flavored Fluids than water.
Wilk B. and O. Bar-Or. Journal of Applied Physiology 80:1112-1117, 1996 Target Sports Diet for Adolescents: Target Sports Diet for Adolescents 55-60 % Carbohydrate
25-30 % fat
15 % protein
Determinants of Exercise Fuel Usage: Determinants of Exercise Fuel Usage Carbohydrates are the preferred fuel for high-intensity work
High-intensity/short duration- glycolytic (lactic acid) pathway for the production of ATP
Only glucose, derived primarily from the breakdown of muscle glycogen can be used.
Very rapid breakdown of muscle glycogen
More rapid during the early stages of exercise CHO Utilization: CHO Utilization Mixed anaerobic-aerobic exercise such as in soccer, football, basketball, swimming and football drills results in a greater breakdown of muscle glycogen
During endurance exercise, glycogen provides 50% of the energy for moderate workout (60% VO2max), but almost 100% for intense workout (> 80% VO2 max)
Carbohydrates in the Diet: Carbohydrates in the Diet Building up and maintaining glycogen stores during training require a CHO rich diet.
Glycogen depletion can occur gradually over repeated days of heavy training when muscle breakdown exceeds its replacement
Carbohydrate Recommendations: Carbohydrate Recommendations Classification of Carbohydrates by Glycemic Index: Classification of Carbohydrates by Glycemic Index When to use GI: When to use GI To increase muscle glycogen especially after intense exercise
Provide 50-100 g of high GI CHO immediately after intense activity
Encourage athletes to continue to eat high CHO to improve glycogen replacement When to use GI: When to use GI Low GI foods may play a role
Athletes who want to minimize changes in blood glucose should select moderate to low GI foods
Athletes who are doing endurance may want to consume moderate to low GI meal before exercise to sustain CHO availability Post-event Carbohydrate: Post-event Carbohydrate 2 hour opportunity that muscles are receptive to carbohydrate
Carbohydrates can be in the form of fluids or food
1.7 gm/kg (during first 2-3 hours post exercise) Pre-exercising Food Guidelines: Pre-exercising Food Guidelines High carbohydrate
Appropriate Portions Meal/Snack Pattern: Meal/Snack Pattern EAR and RDA for Protein: EAR and RDA for Protein *RDA or g/d based on average weight/age (reference individual) How Much Protein is needed?: How Much Protein is needed? Average Teen consumes 1.3g/kg/d
Athletes beginning training
May need 1.2-1.4 g/kg/d
May need 1.4-1.8 g/kg
Athletes who chronically restrict Kcal
May need 1.5-1.7 g/kg/d
Sports Supplements: Sports Supplements How Many Teens Are Actually Taking Supplements?: How Many Teens Are Actually Taking Supplements? A 2003 nationally representative survey conducted by Blue Cross and Blue Shield revealed that as many as 1.1 million people ages 12-17 have taken potentially dangerous performance enhancing supplements and drugs.
76% could not identify any negative side-effects that might result from using steroids, ephedra and other similar substances. BCBS Survey: BCBS Survey Among all youth surveyed, who knew someone using performance-enhancing substances, 38% used creatine and 34% used steroids
27% of the teens were taking the substance to “look better”, a 19% increase from 2001.
Football players were thought to use substances the most but baseball players usage was thought to have increased from 22% to 27% since 2001. BCBS Survey: BCBS Survey Parents viewed the use of performance-enhancing supplements and drugs as their number one concern in youth sports at 39%.
More than aggressive behavior, competitiveness and injury.
Yet, 81% of teens said they had never had a conversation about it with their parents. Supplement Regulation: Supplement Regulation If marketed prior to 1994, no FDA review required on their safety.
For a new dietary ingredient, FDA must be notified of how the product had reasonable evidence determined for safe human use.
However, manufacturers do not have to provide the FDA with evidence of safety or effectiveness. Supplement Standardization: Supplement Standardization Quality control depends on the producer; no strict quality control regulation by the FDA.
No standardization required in the United States. Nutrient Supplements(from Bright Futures in Practice: Physical Activity): Nutrient Supplements (from Bright Futures in Practice: Physical Activity) Nutrient Supplements(from Bright Futures in Practice: Physical Activity): Nutrient Supplements (from Bright Futures in Practice: Physical Activity) Do Extra Amino Acids Help? : Do Extra Amino Acids Help? Consumption of large amounts of single AA
Metabolic imbalances and absorption problems
Most high protein foods associated with high fat which has the possibility of be atherogenic Dangers of excessive Protein: Dangers of excessive Protein The breakdown of protein requires more fluids- this is critical in hot humid weather
The breakdown of protein requires almost 2x as much fluid as the breakdown of CHO or fat.
Excessive protein has also been shown to increase calcium loss- this is especially important in female athletes Creatine: Creatine Introduced in 1992
Most widely used ergogenic supplement
41-48% of male college athletes reported use
Annual sale of greater than $200 million
Creatine- What is it?: Creatine- What is it? Naturally occurring compound
Found in fresh fish and meat
Excreted by kidney, where it is broken down to creatinine
Increases work capacity over brief, repetitive exertion by increasing resting phosphocreatine levels in muscle.
Creatine: Results: Creatine: Results May delay fatigue of workouts for athletes in power sports (football, weight lifters)
May be effective for simple, short-duration, maximal effort anaerobic events
Does not improve endurance
Creatine Adverse Effects: Creatine Adverse Effects Generally regarded as safe, but risks more likely to occur at doses of 20 g/d or higher
Early weight gain from water retention
Muscle cramping, stomach cramping, hydration issues
Case reports of reversible renal problems
No long term data- do not know if endogenous creatine production is reduced
Not tested in those younger than 18 years Creatine: Legal Issues: Creatine: Legal Issues Not banned by IOC.
33 professional athletic teams have banned use
The NCAA prohibits distribution within training facilities.
BUT NOT BANNED BY HIGH SCHOOLS Caffeine: What is it?: Caffeine: What is it? Xanthine derivative
Coffee (100 to 150 mg/cup)
Tea (30-70 mg/cup)
Cola (30-45 mg/can)
Chocolate bar (30 mg/serving)
NoDoz (200 mg/pill)
Found in some analgesic pills. Caffeine: Caffeine Results
Appears to reduce the perception of fatigue, thus allowing for further performance.
Restlessness, nervousness, insomnia, and diuresis
Excessive doses can interfere with performance.
Caffeine: Legal issues: Caffeine: Legal issues Excessive levels banned by certain sports governing agencies (IOC, NCAA).
Recommend < 250mg/day which =
4 – 12oz. Mountain Dews (2.5-20oz. Svg.)
2 Red Bull Energy Drinks
< ½ - Tall Starbucks coffee (12oz.=375mg)
2 NoDoz Energy Pills
1 ½ Tall Coffee Frappuccino
BUT NOT BANNED IN HIGH SCHOOLS Ephedrine: What is it?: Ephedrine: What is it? Alkaloid found naturally in ephedra herb plants, such as “ma huang”
Often found combined with “guarana”, an herbal form of caffeine Ephedrine: Adverse Effects: Ephedrine: Adverse Effects Serious cardiovascular and central nervous system events, including:
Effects are potentiated by caffeine- combination can be deadly www.mayoclinic.com
Ephedrine: Legal Issues: Ephedrine: Legal Issues FDA banned sales of Ephedra (Feb. 2004)
Herbal forms of ephedrine available over-the-counter.
Reformulated in lower doses
Further Information: Further Information International Olympic Committee
National Collegiate Athletic Association
National Center for Drug-Free Sport
World Anti-Doping Agency
AAP Sports Shorts Online
Many Youth Are Physically Inactive: Many Youth Are Physically Inactive - CDC, 2004. Association of State and Territorial Health Officers-ASTO Slide46: An average increase of $395/yr in inpatient and ambulatory care
36% higher health costs overall
A 77% increase in medication costs
An estimated $117 billion in Medicaid (2000) - Strum, 2002. Obesity = Increased Medical Expenses Association of State and Territorial Health Officers-ASTO State health agencies can: State health agencies can shape the community of tomorrow by supporting healthy behaviors in youth today. Association of State and Territorial Health Officers-ASTO Why focus on physical activity?: Why focus on physical activity? Regular physical activity controls weight
Contributes to healthy bones and muscles
Reduces anxiety and depression
Reduces risk for leading causes of morbidity and mortality - Surgeon General Report, 1996. Association of State and Territorial Health Officers-ASTO State health agencies can —: State health agencies can — Provide information to individuals and communities
Design policies and environments that promote healthy living
Ensure effective program implementation and strategic use of scarce resources.
Association of State and Territorial Health Officers-ASTO Promote statewide interagency collaboration to improve health outcomes Lead planning efforts focused on health promotion and disease prevention Coordinate efforts among key stakeholders: Promote statewide interagency collaboration to improve health outcomes Lead planning efforts focused on health promotion and disease prevention Coordinate efforts among key stakeholders Develop a plan that coordinates existing resources Association of State and Territorial Health Officers-ASTO Consider the following actions: Consider the following actions Conduct an environmental scan
Coordinate internal agency efforts
Convene strategic partners
Develop targeted health messages
Provide technical assistance - Fierro, 2002. Association of State and Territorial Health Officers-ASTO State health agencies can’t do it alone!: State health agencies can’t do it alone! Association of State and Territorial Health Officers-ASTO Involving the education community is essential.: Involving the education community is essential.
State and local health agencies can work together with partners to develop and expand physical activity programs in communities and schools. Association of State and Territorial Health Officers-ASTO Promote innovative policy-based approaches: Promote innovative policy-based approaches
Engage new partners
Change the environment
Legitimize use of staff time and resources to promote activity among youth Association of State and Territorial Health Officers-ASTO Partnering with Schools: Partnering with Schools Vending Machines: Vending Machines Accounts for 3% of all teen-eating occasions
Typical Purchase $0.75
$736 million in vending machine sales
78% of this occurs at school Frequency of Competitive Foods: Frequency of Competitive Foods Vending machine or a school store, canteen, or snack bar where students could purchase food or beverages (School Health Policies and Programs Study)
43% of elementary,
73.9% of middle/junior high, and
98.2% of senior high schools
Influence of Income: Influence of Income Income from competitive food sales, including vending machines, primarily from carbonated beverages but also bottled water, to support discretionary spending not related to school foodservice. Examples: Examples Best
Fruit and oatmeal bars
Rice Krispie treats
Breakfast bars Student Health Task Force: SBOE-Alabama: Student Health Task Force: SBOE-Alabama Fundraising Activities
All fundraising activities that involve the selling of food should reinforce food choices that promote good health. Fund Raising Ideas: Fund Raising Ideas
Things to Do
• Gift wrapping • Fun runs
• Magic shows • Family glamour portraits
• Walk-a-thons • Treasure hunt/scavenger hunt
• Bike-a-thons • Tennis/horseshoe competition
• Jump-rope-a-thons • Raffle (movie passes, theme bags)
• Rent-a-teen helper (rake leaves, • Workshops/classes
mow lawns, walk dogs) • Festivals
• Carnivals (Halloween, Easter) • Recycling cans/bottles/paper
• Dances (kids, father, daughter, family) • Golf Tournament
• Skate night/skate-a-thon • Bowling/ bowl-a- thon
Pouring Rights Contracts: Pouring Rights Contracts Exclusive distribution
Increase the percentage of profits when sales volume increases, and this is a substantial incentive for schools to
promote soft drink consumption by adding vending machines,
increasing the times they are available,
marketing the products to students Slide63: Does food advertising and marketing influence children’s food preferences, eating behavior, and weight status? Growth in New Food Products Targeted to U.S. Children and Youth 1994 to 2004: Growth in New Food Products Targeted to U.S. Children and Youth 1994 to 2004 New products targeted to total market New products targeted to children & youth Source: Williams J. 2005b. Product Proliferation Analysis for New Food and Beverage Products
Targeted to Children, 1994–2004. University of Texas at Austin Working Paper. Effects of Food Promotion on Children’s Food Preferences and Behavior: Effects of Food Promotion on Children’s Food Preferences and Behavior Strength of Evidence
Purchase-related behavior Strong
Consumption Modest G. Hastings et al., 2003 Review The Extent and Nature of Food Promotion to Children Slide66: State Health Agencies have a vital role in helping schools and communities
increase the levels of
physical activity in youth
reducing the number of youth who are overweight and at risk
for other health problems Association of State and Territorial Health Officers-ASTO