Sport Food Supplements (how) do they work? Prof. Renger Witkamp

Transcription

1 Sport Food Supplements (how) do they work? Prof. Renger Witkamp 1

2 There is a lot 104,000,000 hits in Google! 2

3 76 pills per day, or almost 1600 in three weeks If you want to survive the Tour the France you really need these things Quote from (nothing yet about EPO) 3

4 supplements non-nutritional ergogenic aids and doping Dietary supplements sport-specific nutrition basic nutrition 4

5 Food supplement (dietary supplement) : foodstuffs the purpose of which is to supplement the normal diet and which are concentrated sources of nutrients or other substances with a nutritional or physiological effect, alone or in combination, marketed in dose form, namely forms such as capsules, pastilles, tablets, pills.. etc Regulated as foods in most countries (some may legally be regarded as medicinal products) 5

6 (lean-) body weight, fat mass Joints etc endurance Nutrient availability recovery Sleep power prevention of disease ability to train 6 mental factors alertness concentration etc. Rewarding & well-being

7 Ergogenic aid (in a broader sense): any nutritional, physical, mechanical, psychologic or pharmacological method or aid to improve physical work capacity or athletic performance 7

8 Why do athletes take supplements? Because they re told to do so! Personal testimonials Coaches and trainers Advertisements Because they belief it helps To improve performance To prevent illnesses To compensate for extra demands during intense training Because competitors use them As compensation for an inadequate diet 8

9 9

10 Lots of hypes and trends (just 1 example) O S O 10

11 Main classes* and examples Metabolic fuels (carbohydrate, lactate, fat) Metabolic aids (bicarbonate, beta-alanine, HMB) Proteins and amino acids Vitamins and anti-oxidants Minerals (including trace elements) Substances that enhance recovery (fluids, electrolytes) Others : caffeine, supplements for joint health, natural pain killers and anti-inflammatory compounds, probiotics, colostrum etc. 11 * different ways of classification possible

12 Caffeine : evidence-based Has shown beneficial effects in different types of sports (endurance, stop-and-go types, high intensity) Effects on acute / single event types of sport less clear Moderate doses effective (few cups of coffee..) Indirect effects should also be considered Example : Rowers' performance in 2,000-m efforts can improve by 2% with 6 mg/kg BM caffeine supplementation (Carr et al., IJSNEM, 2011) 12

13 Recent example The present study illustrates that both caffeine (5 mg/kg/bw) and coffee (5 mg/kg/bw) consumed 1 h prior to exercise can improve endurance exercise performance. 13

14 Creatine Nitrogen containing endogenous substance (liver, pancreas, kidneys) Precursor of creatine-phosphate (phosphocreatine) Topselling product (many tons per year) Works in short and intense bursts of strenght (and speed) Not recommended for long distance etc. May keep water, increase weight Aids production of phospho-creatine 14

15 Effects in sports: Improvement in short bouts of activities that require high levels of strength and power Possibly beneficial to preventing injury Not effective for enhancement of endurance activities 15

16 Effects: Buford et al * : most effective ergogenic product currently available to athletes 20 to 25 g / day creatine increases muscle content of creatine by 20% to 30%. A plateau is reached by using 5 g creatine, 4 times a day for 5 to 6 days (loading phase), followed by a maintenance (postloading) phase of 2-3 g / day. Buford et al * : 3 days 0.3 gram/kg/day as loading dose, followed by 3-5 gram/day (see also Book) But for field hockey? No consensus (but use reported in team sports, lower doses) * J int soc sports nutrition

17 Side-effects : Weight gain (1-2 kg, rapid) (disadvantage in endurance athletes and in continuous- type exercise interspersed with high- intensity exercise (e.g., football, basketball, etc). Muscle cramps (sometimes) GI disturbances 17

18 The youngest kid on the block Kelly et al (March 2013, online) dietary nitrate supplementation improved endurance during severe-intensity exercise in recreationally-active subjects without significantly increasing either the critical power or curvature constant 18

19 Dose-effect relation of a nutrient homeostasis Dose 19

20 More is not automatically better; sometimes even worse PNAS

21 Pharmacological dose-effect relation Dosis 21

22 The Future : towards personalized sports nutrition and supplementation? Resistance exercise stimulates a prolonged elevation of muscle protein synthesis (MPS) that can remain elevated for 24 h (dashed lines). Churchward-Venne et al. Nutrition & Metabolism :40 22

23 Take home messages Nutritional supplements: sometimes useful Ergogenic supplements: caffeine (the rest?) Use supplements under dietary supervision Beware of contamination Miracles don t exist (for the time being) Science in sports nutrition is moving 23