Dr Gary Slater - Supplement use in sports - Ongoing controversies
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Transcript of Dr Gary Slater - Supplement use in sports - Ongoing controversies
Sports Supplements…
Current Controversies
Gary Slater PhD APD Adv. ASD
Senior Lecturer (Masters of Sports Nutrition) University of the Sunshine Coast
National Performance Nutrition Coordinator ARU
Session Overview
• The current environment
• Product formulation…
– Evidence based vs marketing hype
• Inadvertent doping risk
• A help or hindrance…
– Could supplement use be impairing training
Sports Supplements
• 88% using supplements
• ‘Polysupplementation’ common
Dascombe et al. Int J Sport Nutr Exerc Metab. 13:274-280, 2010.
Majority of athletes did NOT know… •Supplement active ingredients (62%)
•Mechanism of action (57%)
•Potential side effects (57%)
•Recommended dosage (54%)
Dascombe et al. Int J Sport Nutr Exerc Metab. 13:274-280, 2010.
Dascombe et al. Int J Sport Nutr Exerc Metab. 13:274-280, 2010.
Majority of athletes used supplements for… •Health benefits
•Ergogenic potential
•On peer recommendations
Within commercial gyms… •Supplement use remains very common (85%)
•Supplementation practices vary by age & training objectives
Goston et al. Nutr. 26:604-611, 2010.
Goston et al. Nutr. 26:604-611, 2010.
Within commercial gyms… •Info primarily from readily accessible sources such as magazines
& other media, friends, health food store
• Athletes seek supplement information from readily accessible sources… – Magazines, on-line
– Fellow athletes, coaches
• Leaves athlete vulnerable to… – Ineffective protocols
– Doping
– Health implications
FitzSimmons & Kidner. J Accid Emerg Med. 15:196-197, 1998. Giampreti et al. Clin Toxicol. 47:827-829, 2009.
Prosser et al. Hum & Exper Toxicol. 28:259-262, 2009. Cons Rep. 75:24-27, 2010.
Session Overview
• The current environment
• Product formulation…
– Evidence based vs marketing hype
• Inadvertent doping risk
• A help or hindrance…
– Could supplement use be impairing training
‘Boron supplementation markedly elevated the
serum concentrations of estradiol & testosterone…’
Nielsen et al. FASEB. 1:394-397, 1987.
Session Overview
• The current environment
• Product formulation…
– Evidence based vs marketing hype
• Inadvertent doping risk
• A help or hindrance…
– Could supplement use be impairing training
Geyer et al. Int J Sports Med. 25:124-9, 2004.
Geyer et al. Int J Sports Med. 25:124-9, 2004.
Supplements & Doping
• Risks associated with supplement use are very real
• Athletes now have access to a much wider array of products domestically & internationally
• Athletes & coaches require global understanding of supplement regulation – Standards controlling labeling laws differ between countries.
In the USA, legislation allows supplement manufacturers to…
• Make claims regarding the effect of a product on the structure/ function of the body, as long as they do not claim to ‘diagnose, mitigate, treat, cure or prevent’ a specific disease
• Make claims for enhanced performance – be they valid or not
Supplements & Doping
• WADA Statement on nutritional supplements… – The ingestion of nutritional supplements pose a
special risk as they may contain or be contaminated with substances that are specifically banned
– As long as the production & sale of such supplements cannot be impeded & their purity cannot be guaranteed, the risk of testing positive in a doping test must be borne by the consumer
– ‘It was reaffirmed that the principle of an athlete’s strict liability for all substances found in his or her system needs to be maintained to protect the integrity of sport & the doping control process’
Session Overview
• The current environment
• Product formulation…
– Evidence based vs marketing hype
• Inadvertent doping risk
• A help or hindrance…
– Could supplement use be impairing training
Gomez-Cabrera et al. Am J Clin Nutr. 87:142-9, 2008.
Vitamin C supplementation
decreases training efficiency because
it prevents some cellular adaptations
to exercise
Gomez-Cabrera et al. Am J Clin Nutr. 87:142-9, 2008.
These results suggest that inhibition
of ROS attenuates some skeletal
muscle cell signalling pathways and
gene expression involved in
adaptations to exercise.
Petersen et al. Acta Physiol. 204:382-92, 2012.
Based on the contradictory evidence regarding the
effects of higher intakes of vitamin C and/or E on
exercise performance and redox homeostasis, a
permanent intake of non-physiological dosages of
vitamin C and/or E cannot be recommended to
healthy, exercising individuals.
Nikolaidis et al. Oxidat Med Cell Long. 2012.
…loading the cell with high doses of
antioxidants leads to a blunting of
the positive effects of exercise
Training…. We recommend that an
adequate intake of vitamins and
minerals through a varied and
balanced diet remains the best
approach…
Athletes should be cautioned about
taking Vitamin C chronically,
however, blackcurrant juice may
improve performance in the elite
Braakhuis et al. Eor J Sports Sci. 2013.
Athletes should be cautioned about
taking Vitamin C chronically,
however, blackcurrant juice may
improve performance in the elite
Braakhuis et al. Eor J Sports Sci. 2013.
Sports Supplements
• Athletes now have access to a much wider array of products domestically & internationally – Require global understanding of supplement regulation
• Engage significant others in education process • Consider establishment of supplement policy
– Base guidance on evidence based practice – Package & promote your system
• Recommendations may vary depending on athlete & resources available, specific goals, dietary intake etc.
• Be prescriptive…What, When, How much & Monitor
• Remain well informed – Talk with athletes – Visit supplement stores – Read both scientific & lay articles