Post on 18-Jan-2016
Nutrition and Nutritional
Supplements in Sports
ObjectivesIncrease awareness that nutrition can affect an
athlete’s performanceDiscuss current nutritional recommendations for
athletesReview the 1994 Dietary Supplement Health and
Education ActDefinition of a supplement Impact of this legislation
Discuss specific nutritional supplements commonly used by athletesDo they work?Are they safe?
Performance Influencing Factors
Genetics
Training and Conditioning
Nutrition
Basics of Nutrition6 Classes of NutrientsMacronutrients
Carbohydrates (CHO)FatsProteins (PRO)
MicronutrientsVitaminsMineralsWater
Determinants of the Athlete’s Energy Requirements
During intense exerciseCarbohydrate stored in muscles and liver
(glycogen) is predominant fuel sourceDuring prolonged exercise
Fat stores are predominant fuel sourceFitness level of the athlete
Well trained endurance athletes burn fat more efficiently, sparing limited glycogen stores
Formula for Rough Estimation of the Body’s Calorie Requirements
Sedentary personWeight (kg) x 25
Moderately active personWeight (kg) x 30
Active person (endurance athlete)Weight (kg) x 40
Underweight personWeight (kg) x 45
kg = lbs / 2.2
CarbohydratesSimple (sugars) and Complex (starches)Major & most efficient fuel source for exercising
muscle
4 kcal/gmAthletes should ingest 6 to10 gm/kg/day
55 to 60 % of total calories should come from carbohydratesComplex carbohydrates (starches) are preferable
During exerciseAthletes should consume 25 to 30 gm of carbohydrate for
every 30 minutes of exerciseAthletes should drink 6 to 8 ounces of water or sports drink
for every 10 to 15 minutes of exercise
CarbohydratesAfter exercise
Athletes should consume 1.0 to 1.5 gm/kg immediately post exercise and again one hour later Decrease in storage efficiency the greater duration
of time To replace muscle glycogen stores To prevent gradual depletion of muscle glycogen
stores over time caused by repetitive daily bouts of heavy exercise
To decrease muscle breakdownChocolate Milk?
Why Complex Carbohydrates?Compared to ingesting simple
carbohydrates (sugar), ingesting complex carbohydrates (starch and fiber):Increases muscle glycogen stores betterImproves performance and delays fatiguePromotes faster stomach emptyingCauses less stomach upset and indigestionLeads to lower blood sugar and insulin levels Provides other beneficial nutrients
Fiber, vitamins and minerals
ProteinAthletes require more protein than non-athletes
15 to 20% of total calories should come from protein4 kcal/gmProtein intake should be tailored to type of training
1.2 to 1.4 gm/kg/day recommended for endurance athletes 1.7 to 1.8 gm/kg/day recommended for strength athletes
Average American diet provides 1.4 gm/kg/dayAdequate calorie intake is just as important as
adequate protein intake for building musclesToo much protein intake can be bad
Excess protein calories are stored as fatExcess protein intake can lead to dehydration and may
contribute to kidney problems
FatMajor source of energy
9 kcal/gm25 to 30% of total calories should come from
fatLess than 10% of total calories should come from
saturated fatsCholesterol intake should be less than 300
mg/dayAverage American diet provides 37% of total
calories from fat
Pre-exercise MealImportance
Less hunger before and during exerciseMaintains optimum glycogen stores
RecommendationsEmphasize complex carbohydrates
(starches) 1 to 4 gm/kg about 1 to 4 hours prior to event Consume less closer to event
Avoid high fat and high protein foods Slower gastric emptying can cause stomach
upsetAvoid high fiber or gas forming foods
Can lead to crampy abdominal pain
Carbohydrate LoadingAthlete should have overall high
carbohydrate dietBody is more efficient at storing CHOIncreases the body’s pre-exercise
glycogen stores by 50 to 100%Benefits endurance athletes who compete
for longer than 90 minutesCan increase endurance up to 20%Can increase performance by 2 to 3%
Carbohydrate Loading:One Example of How
Days prior to eventExercise duration Carbohydrate intake
6 90 minutes 5 gm/kg/day 5 40 minutes 5 gm/kg/day 4 40 minutes 5 gm/kg/day 3 20 minutes 8 gm/kg/day 2 20 minutes 8 gm/kg/day 1 rest 8 gm/kg/day
Body CompositionMeasures
HydrostaticElectrical impedanceSkinfold thickness
Endurance AthletesMen: 8-12%Women: 10-18%
NOT BELOWMen: 3%Women: 12%
Weight ControlBody Composition
Refers to fat and non fat componentsPercentage of body fatLean body weight
Two FactorsNumber of adipose (fat) cellsSize of adipose cells
1 lb. of fat = ~3500 kcal
Weight Loss & GainWeight Loss
Safe weight loss is 1-2 lbs. per weekExercise utilizes fat stores 80-90% with almost
no loss of lean massDieting alone may decrease lean mass 35-40%
Weight GainApproproiately gain 1-2 lbs. per weekAim to increase lean body massAdd 500-1000 kcal a weekMUST include weight training
Nutritional Supplements1994 Dietary Supplement Health and
Education ActDefinition of a supplement
Any product that contains vitamins, minerals, amino acids, herbs, botanicals or a concentrate, metabolite, constituent, extract or combination of any of these ingredients
Removed dietary supplements from FDA regulation on the front end
FDA must prove a supplement is dangerous before its sale can be prohibited
Nutritional Supplements1994 Dietary Supplement Health and
Education ActManufacturers do not have to provide scientific
proof of claimsManufacturers cannot state product is meant
to diagnose, treat, prevent or cure a disease but can make indirect suggestions
Created a multi-billion dollar industry that continues to grow rapidly
Vitamins and MineralsEssential nutrients
Human body needs these to produce energyNo evidence in U.S. studies that taking vitamin
and mineral supplements improves athletic performanceBeing deficient in vitamins or minerals is rare in the
U.S. compared to the rest of the worldA few studies outside U.S. showed an effect
Did population studied have some baseline deficiency treated with these supplements?
Vegetarian athletes are at risk for being deficient in vitamins B12, D, riboflavin, iron, zinc and calciumAthletes who are strict vegetarians should take a
multivitamin to prevent deficiencies and a calcium supplement (1000 mg/day) to help prevent bone loss
Anabolic Steroids and Anabolic Steroid Precursors
Are banned and tested for by the USOC, IOC, NCAA, NFL, NBA and MLB
NHL has no official policy and does not perform testing
You can be disqualified from participating in college sports if you test positive for a substance banned by the NCAAWhether or not you knew it was bannedWhether or not the product was mislabeled
Buyer Beware! IOC funded study by Shanzer (Germany) from 10/00 to
11/01 Analyzed 634 products labeled as non-hormonal nutritional
supplements from 13 countries and 215 different suppliers 94 products (14.8%) were found to be “positive supplements”
(contained anabolic steroid precursors not declared on the label) Anabolic androgenic steroid concentrations ranged from 0.01 to
190 micrograms per gram of supplement 23 products contained steroid precursors of nandrolone and
testosterone 64 products contained steroid precursors of testosterone only 7 products contained steroid precursors of nandrolone only Percentage of positive supplements per country
25.8% of products bought in Netherlands 22.7% of products bought in Austria 18.8% of products bought in UK 18.8% of products bought in US (45 positive out of 240 tested)
ConclusionsNutrition plays an important role in an
endurance athlete’s ability to performProper nutrition in combination with
sound and proven training techniques can help endurance athletes to maximize their genetic abilities
Certain nutritional supplements have not demonstrated any performance benefit in studies
ConclusionsCertain nutritional supplements can have
potentially dangerous side effectsFurther legislation is needed to address the
dangers of some nutritional supplementsProfessionals in the community need to be
resources of good information for athletes, parents and coaches PhysiciansPhysician assistantsNurse practitionersAthletic trainersSchool nursesDieticians