Transcript Sports Nutrition

Nutrition and Nutritional
Supplements in Sports
Sean T. Bryan, MD, FAAFP
Assistant Clinical Professor of Family Medicine,
Medical College of Georgia and
Mercer University School of Medicine
Program Director,
Southwest Georgia Family Medicine Residency
Fellowship Director,
Southwest Georgia Sports Medicine Program
Phoebe Putney Memorial Hospital
Albany, GA
‫نخستین وبسایت تخصصی دانشجویان‬
‫رشته تربیت بدنی و علوم ورزشی‬
‫‪The first specialized website‬‬
‫‪for PE students‬‬
Objectives
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Increase awareness that nutrition can affect an athlete’s
performance
Discuss current nutritional recommendations for athletes
Review the 1994 Dietary Supplement Health and
Education Act
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Discuss specific nutritional supplements commonly used
by athletes
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Definition of a supplement
Impact of this legislation
Do they work?
Are they safe?
Review the Anabolic Steroid Control Act of 2004
Help providers answer questions and address concerns
of athletes, parents and coaches
Performance Influencing Factors
Genetics
Training
Nutrition
and Conditioning
Determinants of the Athlete’s
Energy Requirements
 During
intense exercise
 Carbohydrate
stored in muscles and liver
(glycogen) is predominant fuel source
 During
 Fat
prolonged exercise
stores are predominant fuel source
 Fitness
 Well
level of the athlete
trained endurance athletes burn fat more
efficiently, sparing limited glycogen stores
Formula for Estimating the
Body’s Calorie Requirements
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Sedentary person
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Moderately active person
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Weight (kg) x 40
Underweight person
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Weight (kg) x 30
Active person (endurance athlete)
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Weight (kg) x 25
Weight (kg) x 45
kg = lbs / 2.2
Recommendations for Athletes
 Carbohydrate
intake
 Pre-exercise meal
 Carbohydrate loading
 Protein intake
 Fat intake
Carbohydrates
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Non-essential nutrient (human body can make sugar)
Simple (sugars) and Complex (starches)
Major fuel source for exercising muscle
Athletes should ingest 6 to10 gm/kg/day
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60 to 70% of total calories should come from carbohydrates
Complex carbohydrates (starches) are preferable
During exercise
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Athletes should consume 25 to 30 gm of carbohydrate for
every 30 minutes of exercise
Athletes should drink 6 to 8 ounces of water or sports drink for
every 10 to 15 minutes of exercise
Carbohydrates
 After
exercise
 Athletes
should consume 1.0 to 1.5 gm/kg
immediately post exercise and again one
hour later
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 breakdown
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Why Complex Carbohydrates?
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Compared to ingesting simple carbohydrates,
ingesting complex carbohydrates:
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Increases muscle glycogen stores better
Improves performance and delays fatigue
Promotes faster stomach emptying
Causes less stomach upset and indigestion
Leads to lower blood sugar and insulin levels
Provides other beneficial nutrients
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Fiber, vitamins and minerals
Pre-exercise Meal
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Importance
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Less hunger before and during exercise
Maintains optimum glycogen stores
Recommendations
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Emphasize complex carbohydrates (starches)
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Avoid high fat and high protein foods
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1 to 4 gm/kg about 1 to 4 hours prior to event
Consume less closer to event
Slower gastric emptying can cause stomach upset
Avoid high fiber or gas forming foods
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Can lead to crampy abdominal pain
Carbohydrate Loading
 Increases
the body’s pre-exercise
glycogen stores by 50 to 100%
 Benefits endurance athletes who
compete for longer than 90 minutes
 Can
increase endurance up to 20%
 Can increase performance by 2 to 3%
Carbohydrate Loading:
One Example of How
Days prior to event Exercise duration
6
90 minutes
5
40 minutes
4
40 minutes
3
20 minutes
2
20 minutes
1
rest
Carbohydrate intake
5 gm/kg/day
5 gm/kg/day
5 gm/kg/day
10 gm/kg/day
10 gm/kg/day
10 gm/kg/day
Protein
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Athletes require more protein than non-athletes
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12 to 18% of total calories should come from protein
Protein intake should be tailored to type of training
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1.2 to 1.4 gm/kg/day recommended for endurance athletes
1.7 to 1.8 gm/kg/day recommended for strength athletes
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Average American diet provides 1.4 gm/kg/day
 Adequate calorie intake is just as important as
adequate protein intake for building muscles
 Too much protein intake can be bad
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Excess protein calories are stored as fat
Excess protein intake can lead to dehydration and may
contribute to kidney problems
Fat
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Major source of energy
 25 to 30% of total calories should come from fat
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Less than 10% of total calories should come from
saturated fats
Cholesterol intake should be less than 300 mg/day
 Average American diet provides 37% of total
calories from fat
Nutritional Supplements
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1994 Dietary Supplement Health and
Education Act
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Definition 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 Supplements
 1994
Dietary Supplement Health and
Education Act
 Manufacturers
do not have to provide
scientific proof of claims
 Manufacturers 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 Minerals
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Essential nutrients
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No evidence in U.S. studies that taking vitamin and
mineral supplements improves athletic performance
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Being deficient in vitamins or minerals is rare in the U.S.
compared to the rest of the world
A few studies outside U.S. showed an effect
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Human body needs these to produce energy
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 calcium
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Athletes who are strict vegetarians should take a
multivitamin to prevent deficiencies and a calcium
supplement (1000 mg/day) to help prevent bone loss
Vitamins and Minerals
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Specific vitamins and minerals studied
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Vitamin A and Vitamin D
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Vitamin E
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No evidence of increased performance
May have toxic effects at high doses
No evidence of increased performance
Toxic effects are rare
Vitamin C
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Anti-oxidant effect may help decrease exercise related
muscle soreness
No effect on strength
Possible toxic effects at high doses
Vitamins and Minerals
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Specific vitamins and minerals studied
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Vitamin B6
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Other anti-oxidants (Betacarotene, Bioflavinoids,
Copper, Cysteine and Glutathione)
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No evidence of increased performance
Toxic over 200 mg/day (nervous system side effects)
May help to protect against exercise induced muscle
damage
Study results are conflicting
Should not exceed 100% U.S. RDA of anti-oxidants
Buyer beware!
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Some supplements have been found to contain up
to 3000% of U.S. RDA for vitamins and minerals
Creatine
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Chemical name: Creatine-Monohydrate
 Naturally available in meat and fish
 NCAA study found creatine supplements used by
12% of college athletes
 A subsequent survey of high school athletes
showed similar usage rates
 Does it work to
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Increase muscle mass?
Increase strength?
Increase performance?
Is it safe?
Creatine
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I found 9 studies showing (+) effects in healthy subjects
published between July 1997 and November 2001
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Increased high intensity, intermittent exercise performance in
squash players
Increased cell hydration status and performance variables in
Division I college football players more than training alone
Augments repeated sprint cycle performance in hot
environment without altering thermoregulatory responses
Increases indices of high intensity exercise performance for
both males and females
Increased capacity of human muscle to perform work during
alternating intensity contraction
Creatine
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Recent studies with (+) effects (continued)
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Ergogenic effect in elite ice hockey players
Loading improves intermittent sprint capacity at end of
endurance exercise to fatigue
Adding creatine to glucose, taurine and electrolyte
supplement promoted greater gains in fat and bone free
mass, isotonic lifting volume and sprint performance during
intense resistance and agility training
Helped to prolong time maximal rate of power output could
be maintained
Creatine
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I found 3 studies with no effect in healthy subjects
published in November and December of 2001
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Did not positively influence isometric strength in untrained
(sedentary) males
Did not increase performance or training volume over
placebo in rowers that performed a high intensity rowing and
strength program
No statistically significant difference in strength or fat free
mass gains after a resistance exercise training program
compared with post exercise protein supplementation
Creatine
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I found 4 studies looking at safety of supplementation
in healthy subjects published from 1997 to 2001
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Retrospective study of 26 athletes who reported taking
creatine between 0.8 and 4 years - blood chemistries
including liver and kidney function were all within normal
Neither 12 weeks of supplementation with training nor
training alone had any effect on serum cholesterol, HDL,
LDL, TG or creatinine levels
Supplementation for 5 days had no effect on BP, serum
creatinine, estimated creatinine clearance or plasma CK
Oral supplementation for 5 days had no effect on GFR, total
protein or albumin excretion rates and all remained normal
Creatine
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My Opinion
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Supplementation in combination with high intensity
strength training increases strength during high intensity
intermittent exercise 7 to 8% more than training alone
Supplementation probably increases performance in
sports involving or requiring high intensity intermittent
bursts of strength
Long term effects (chronic use > 4 years) are not known
and I share concern of some experts about potential for
liver and kidney problems
Dosing
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Loading: 20 to 30 gm/day for one week
Maintenance: 10 to 15 gm/day while training
HMB
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Chemical name: Hydroxy-Methylbutyrate
Metabolite of leucine (amino acid)
Available naturally in catfish, citrus fruits and
breastmilk
Some preliminary studies suggest that
supplementation with HMB can suppress muscle
protein breakdown
One placebo-controlled study in weightlifters reported
slightly better strength increases and greater lean
mass increases in the group taking HMB
No known adverse effects
Dosing: 1 gm three times a day
Ephedra or MaHuang
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Herbal forms of the stimulant ephedrine
80 confirmed deaths related to ephedra use
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Experts suspect many more unconfirmed deaths
Adverse effects
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High blood pressure (most common)
Palpitations and increased heart rate
Seizure
Thermoregulatory dysfunction
Stroke
Heart attack
Sudden death
Vasculitis
Allergic myocarditis (one case reported)
Acute hepatitis (one case report)
Ephedra or MaHuang
 Following
the death of two professional
athletes, FDA banned sale of Ephedra
as a nutritional supplement
 Since this time, manufacturers have
started substituting other stimulants
 Citrus
Aurantium
Orange extract
 Chemical structure very similar to ephedrine
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Other Nutritional Supplements
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Chromium Picolinate
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L-Carnitine
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No benefit demonstrated in studies
Adverse effects: stomach upset, anemia, cognitive
impairment, chromosome damage, interstitial
nephritis
No benefit demonstrated in studies
Adverse effect: significant muscle weakness
L-Tryptophan
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No benefit demonstrated in studies
Adverse effect: eosinophilia myalgia syndrome
Anabolic Steroid Precursors
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Dehydroepiandrosterone (DHEA) and
Androstenedione (“Andro”)
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Chemicals that can be converted into testosterone
in human biochemical pathways
Naturally available in wild yams
An early study done by a manufacturer of these
products showed no significant increase in blood
levels of testosterone
 Study looked at lower doses of these
supplements than are usually taken and did not
measure ratio of testosterone to
epitestosterone (T:E ratio)
Anabolic Steroid Precursors
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Subsequent independent scientific studies
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DHEA
 Does not seem to have much if any effect on fat-free
body mass and strength
Androstenedione
 Causes a temporary increase in testosterone levels
 Has no effect on body’s ability to make protein
 Does not seem to have any effect on strength
 No long term effect on blood testosterone levels
 Chronic use causes increase in estrogen levels
Anabolic Steroid Precursors
 Potential
adverse effects
 May
cause liver damage
 In females
Can cause male features in women
 May increase risk of uterus cancer
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 In
males
Can cause female features in men
 May increase risk of prostate cancer
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Anabolic Steroids and
Anabolic Steroid Precursors
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Are banned and tested for by the USOC, IOC,
NCAA, NFL, NBA and MLB (finally!)
 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 NCAA
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Whether or not you knew it was banned
Whether or not the product was mislabeled
Buyer Beware!
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IOC funded study by Shanzer (Germany) from 10/00 to 11/01
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Analyzed 634 products labeled as non-hormonal nutritional
supplements from 13 countries and 215 different suppliers
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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
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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)
Anabolic Steroid Control Act of 2004
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Signed into federal law on October 22, 2004
Amends the Anabolic Steroid Control Act of 1990
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Modifies the definition of anabolic steroids to include
tetrahydrogestrinone (THG), androstenedione, and specified
related chemicals
Directs the U.S. Sentencing Commission (USSC) to review federal
sentencing guidelines with respect to anabolic steroid-related
offenses
Amends guidelines to provide for increased penalties
Authorizes the Attorney General to exempt from regulation any
compound, mixture, or preparation containing an anabolic steroid
that does not present a significant abuse potential
Directs the Secretary of Health and Human Services to award
grants for science-based education programs in elementary and
secondary schools to highlight the harmful effects of anabolic
steroids and to ensure that the NSDUH includes questions
concerning the use of these drugs.
Source: Library of Congress
Conclusions
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Nutrition plays an important role in an endurance
athlete’s ability to perform
Proper nutrition in combination with sound and
proven training techniques can help endurance
athletes to maximize their genetic abilities
Creatine
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Has been shown to increase strength during intermittent
high intensity exercise
Has not been shown to improve performance in
endurance athletes
Safety of long-term use is not known
Certain nutritional supplements have not
demonstrated any performance benefit in studies
Conclusions
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Certain nutritional supplements can have
potentially dangerous side effects
Further legislation is needed to address the
dangers of some nutritional supplements
Professionals in the community need to be
resources of good information for athletes,
parents and coaches
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Physicians
Physician assistants
Nurse practitioners
Athletic trainers
School nurses
Dieticians
Questions?
Thank You!
References
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Bemben MG, Bemben DA, Loftiss DD, Knehans AW. Creatine supplementation
during resistance training in college football athletes. Med Sci Sports Exerc
2001;33(10):1667-73.
Bemben MG, Tuttle TD, Bemben DA, Knehans AW. Effects of creatine
supplementation on isometric force-time curve characteristics. Med Sci Sports
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Bosco C, Tihanyi J, Pucspk J, Kovacs I, Gabossy A, Colli R, Pulvirenti G,
Tranquilli C, Foti C, Viru M, Vira A. Effect of oral creatinine supplementation on
jumping and running performance. Int J Sports Med 1997;18(5):369-72.
Fuentes RJ and Rosenberg JM. Athletic Drug Reference ’99. Durham (NC):
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Society for Sports Medicine Annual Meeting, Orlando (FL), April 2002.
Haller CA, Benowitz NL. Adverse cardiovascular and central nervous system
events associated with dietary supplements containing ephedra alkalloids. N
Engl J Med 2000;343(25):1833-8.
Jackson C. Vitamin and Mineral Use and Controversies for Strength Training.
Presented at American College of Sports Medicine Annual Meeting, St. Louis
(MO), May 2002.
References
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Jones AM, Atter T, Georg KP. Oral creatine supplementation improves multiple
sprint performance in elite ice-hockey players. J Sports Med Phys Fitness
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Kreider RB, Ferreira M, Wilson M, Grindstaff P, Plisk S, Reinardy J, Cantler E,
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Mihic S, MacDonald JR, McKenzie S, Tarnopolsky MA. Acute creatine loading
increases fat-free mass, but does not affect blood pressure, plasma creatinine,
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References
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Romer LM, Barrington JP, Jeukendrup AE. Effects of oral creatine
supplementation on high intensity, intermittent exercise performance in
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Schilling BK, Stone MH, Utter A, Kearney JT, Johnson M, Coglianese R, Smith
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Tarnopolosky MA, Parise G, Yardley NJ, Ballantyne CS, Olatinji S, Phillips SM.
Creatine-dextrose and protein-dextrose induce similar strength gains during
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References
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Tarnopolosky MA, MacLennan DP. Creatine monohydrate supplementation
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Vahedi K, Domigo V, Amarenco P, Bousser MG. Ischaemic stroke in a
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Vandebuerie F, Vanden Eynde B, Vandenberghe K, Hespel P. Effect of creatine
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References
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American College of Sports Medicine Annual Meeting, St. Louis (MO), May
2002.
 Zaacks SM, Klein L, Tan CD, Rodriguez ER, Leikin JB. Hypersensitivity
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 http://www.usdoj.gov/ndic/pubs11/12620/steroids.htm
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