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BJSM reviews: A–Z of supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance Part 1 Louise M Burke, 1 Lindy M Castell, 2 Samantha J Stear 3 ‘‘Nutraceuticals, functional foods, diet- ary supplements, ergogenic aids, food supplements, performance boosting sup- plements…’’ All the above terms (and more) have been used to entice the unwary (and wary!) athlete to spend money on dietary pro- ducts that claim to enhance their health and sports performance. The Oxford English Dictionary defini- tion of supplement is: ‘‘Something added to supply a deficiency’’. Yet many supple- ments, or their individual ingredients, are nutrients or food chemicals for which the body does not have an estimated or theoretical requirement. Thus there are clearly other factors that underpin their use by athletes. Athletes choose to consume a supple- ment for a number of reasons, including: c To prevent or treat a perceived nutri- ent deficiency, especially when requirements for a nutrient are increased by their exercise programme c To provide a more convenient form of nutrients in situations where every- day foods aren’t practical—particu- larly to address nutritional needs/ goals around an exercise session c To provide a direct ergogenic (perfor- mance-enhancing) effect c Because they believe every top athlete is consuming it and they can’t afford to miss out. Before deciding to use a supplement, athletes should always consider the issues of efficacy, safety and legality/ethics asso- ciated with the product. Unfortunately, in many cases, specific information is limited. Studies examining the performance-enhan- cing effects of the enormous array of supplements are relatively few, especially investigations on real-life sports events and elite performers in the field. Studies invol- ving specialised subpopulations such as paralympic athletes are even rarer (personal communication, Jeanette Crosland, BPA consultant dietitian). Therefore decisions about efficacy must often be extrapolated from the best available research rather than clear-cut evidence. Decisions on safety should examine the possibility of taking a toxic dose of a compound either through indiscriminate supplement use or the belief that ‘‘if a little is good, more is better’’. However, safety issues should also consider any medical concerns that may conflict with sports nutrition goals or advice. For example: recommended protein require- ments are reduced in diabetes; hyperten- sion may have implications for sodium intake; and some medical conditions may contraindicate the use of caffeine. Supplement dosages for special groups such as wheelchair athletes may need to be altered because of decreased active muscle mass (personal communication, Jeanette Crosland, BPA consultant dieti- tian). A final consideration in the safety of supplements is the issue of purity of products and the risk of consuming contaminants that are either directly harmful or banned by the anti-doping codes under which elite sport is organised. The ethical/legality issues of sport can be contravened either by deliberate use of over-the-counter compounds that are prohibited by such codes (eg, prohor- mones and stimulants) or by inadvertent intake of these products when they are hidden in products. The contamination of supplements with prohibited substances is a topical issue in sport and is examined in greater detail below. CONTAMINATION ISSUES One of the key factors that elite athletes need to consider in negotiating the com- plex world of supplements and sports foods is whether the consumption of these products could lead to an inadver- tent case of doping. Following the wave of nandrolone findings in the late 90s, several studies have sought to explore the extent of contamination. In 2000–01, the International Olympic Committee (IOC) funded an extensive research project using the then IOC-accredited laboratory in Cologne to analyse independently 634 non- hormonal nutrition supplements purchased across 13 countries. This pivotal research confirmed the contamination issue, with 15% (94 products) being found to contain undeclared steroids banned by the World Anti-Doping Agency (WADA, www.wada- ama.org). Altogether, 289 samples (21% positives) were from companies that were known to sell steroids/prohormones but, perhaps more worrying, 345 samples (9.6% positives) came from companies that did not sell steroids/prohormones. Results of the IOC Cologne Study continue to be confirmed, illustrating that the issue of contamination is still around. In 2007, HFL Sport Science (a WADA- experienced laboratory, part of the Quotient Bioscience group) in the UK analysed 58 supplements purchased through standard retail outlets in the USA. They found that 25% were con- taminated with prohibited steroids and 11% were contaminated with prohibited stimulants (personal communication, Catherine Judkins, HFL Sport Science). In 2008, HFL Sport Science followed this up with the analysis of 152 products purchased from standard retail outlets in the UK and found that over 10% were contaminated with steroids and/or stimu- lants (personal communication, Catherine Judkins, HFL Sport Science). The assumption has generally been that the presence of WADA-prohibited sub- stances is the result of inadvertent con- tamination of raw materials and/or cross- contamination during the manufacturing or packaging process rather than deliber- ate adulteration of the products in an attempt to increase the supplement’s effectiveness. Consequently, the amounts of steroids detected have been extremely variable, even within a single batch, but have generally been extremely small. However, very low levels of contamina- tion (measured in parts per billion) can cause positive drug tests in an elite athlete at a level much lower than acceptable impurity levels (typically around 0.01%) 1 Australian Institute of Sport, Canberra, Australia; 2 University of Oxford, Oxford, UK; 3 English Institute of Sport, London, UK Correspondence to: Dr L M Castell, Green Templeton College, University of Oxford, Oxford OX2 6HG, UK; lindy. [email protected] Editorial 728 Br J Sports Med September 2009 Vol 43 No 10 group.bmj.com on December 8, 2014 - Published by http://bjsm.bmj.com/ Downloaded from

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Page 1: BJSM reviews: A-Z of supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance Part 1

BJSM reviews: A–Z ofsupplements: dietarysupplements, sports nutritionfoods and ergogenic aids forhealth and performance Part 1Louise M Burke,1 Lindy M Castell,2 Samantha J Stear3

‘‘Nutraceuticals, functional foods, diet-ary supplements, ergogenic aids, foodsupplements, performance boosting sup-plements…’’

All the above terms (and more) have beenused to entice the unwary (and wary!)athlete to spend money on dietary pro-ducts that claim to enhance their healthand sports performance.

The Oxford English Dictionary defini-tion of supplement is: ‘‘Something addedto supply a deficiency’’. Yet many supple-ments, or their individual ingredients, arenutrients or food chemicals for which thebody does not have an estimated ortheoretical requirement. Thus there areclearly other factors that underpin theiruse by athletes.

Athletes choose to consume a supple-ment for a number of reasons, including:

c To prevent or treat a perceived nutri-ent deficiency, especially whenrequirements for a nutrient areincreased by their exercise programme

c To provide a more convenient form ofnutrients in situations where every-day foods aren’t practical—particu-larly to address nutritional needs/goals around an exercise session

c To provide a direct ergogenic (perfor-mance-enhancing) effect

c Because they believe every top athleteis consuming it and they can’t affordto miss out.

Before deciding to use a supplement,athletes should always consider the issuesof efficacy, safety and legality/ethics asso-ciated with the product. Unfortunately, inmany cases, specific information is limited.

Studies examining the performance-enhan-cing effects of the enormous array ofsupplements are relatively few, especiallyinvestigations on real-life sports events andelite performers in the field. Studies invol-ving specialised subpopulations such asparalympic athletes are even rarer (personalcommunication, Jeanette Crosland, BPAconsultant dietitian). Therefore decisionsabout efficacy must often be extrapolatedfrom the best available research rather thanclear-cut evidence.

Decisions on safety should examine thepossibility of taking a toxic dose of acompound either through indiscriminatesupplement use or the belief that ‘‘if alittle is good, more is better’’. However,safety issues should also consider anymedical concerns that may conflict withsports nutrition goals or advice. Forexample: recommended protein require-ments are reduced in diabetes; hyperten-sion may have implications for sodiumintake; and some medical conditions maycontraindicate the use of caffeine.Supplement dosages for special groupssuch as wheelchair athletes may need tobe altered because of decreased activemuscle mass (personal communication,Jeanette Crosland, BPA consultant dieti-tian).

A final consideration in the safety ofsupplements is the issue of purity ofproducts and the risk of consumingcontaminants that are either directlyharmful or banned by the anti-dopingcodes under which elite sport is organised.The ethical/legality issues of sport can becontravened either by deliberate use ofover-the-counter compounds that areprohibited by such codes (eg, prohor-mones and stimulants) or by inadvertentintake of these products when they arehidden in products. The contamination ofsupplements with prohibited substancesis a topical issue in sport and is examinedin greater detail below.

CONTAMINATION ISSUESOne of the key factors that elite athletesneed to consider in negotiating the com-plex world of supplements and sportsfoods is whether the consumption ofthese products could lead to an inadver-tent case of doping. Following the wave ofnandrolone findings in the late 90s,several studies have sought to explorethe extent of contamination. In 2000–01,the International Olympic Committee(IOC) funded an extensive research projectusing the then IOC-accredited laboratory inCologne to analyse independently 634 non-hormonal nutrition supplements purchasedacross 13 countries. This pivotal researchconfirmed the contamination issue, with15% (94 products) being found to containundeclared steroids banned by the WorldAnti-Doping Agency (WADA, www.wada-ama.org). Altogether, 289 samples (21%positives) were from companies that wereknown to sell steroids/prohormones but,perhaps more worrying, 345 samples (9.6%positives) came from companies that didnot sell steroids/prohormones.

Results of the IOC Cologne Studycontinue to be confirmed, illustrating thatthe issue of contamination is still around.In 2007, HFL Sport Science (a WADA-experienced laboratory, part of theQuotient Bioscience group) in the UKanalysed 58 supplements purchasedthrough standard retail outlets in theUSA. They found that 25% were con-taminated with prohibited steroids and11% were contaminated with prohibitedstimulants (personal communication,Catherine Judkins, HFL Sport Science).In 2008, HFL Sport Science followed thisup with the analysis of 152 productspurchased from standard retail outlets inthe UK and found that over 10% werecontaminated with steroids and/or stimu-lants (personal communication, CatherineJudkins, HFL Sport Science).

The assumption has generally been thatthe presence of WADA-prohibited sub-stances is the result of inadvertent con-tamination of raw materials and/or cross-contamination during the manufacturingor packaging process rather than deliber-ate adulteration of the products in anattempt to increase the supplement’seffectiveness. Consequently, the amountsof steroids detected have been extremelyvariable, even within a single batch, buthave generally been extremely small.However, very low levels of contamina-tion (measured in parts per billion) cancause positive drug tests in an elite athleteat a level much lower than acceptableimpurity levels (typically around 0.01%)

1 Australian Institute of Sport, Canberra, Australia;2 University of Oxford, Oxford, UK; 3 English Institute ofSport, London, UK

Correspondence to: Dr L M Castell, Green TempletonCollege, University of Oxford, Oxford OX2 6HG, UK; [email protected]

Editorial

728 Br J Sports Med September 2009 Vol 43 No 10

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Page 2: BJSM reviews: A-Z of supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance Part 1

in good manufacturing practice regula-tions. It is important to note that, althoughthis minimal amount of contaminationcould produce dire consequences for anathlete competing under the WADA code,in most cases, this amount is unlikely tocause detrimental health problems for thegeneral consumer. There are daily foodproduct withdrawals and recalls because ofmislabelling and undeclared allergens. This,together with concerns about impuritiesand contamination from medicine residues,insects and small pieces of metal andplastic, shows that inadvertent contamina-tion is not just a problem for sportsnutrition products.

The inadequate regulation of dietarysupplements means there is no way forconsumers to know what many supple-ments actually contain or how pure theproduct and its ingredients are.Manufacturers with good-quality controlsand banned substance testing are betterable to control the risk. The inception ofthe WADA code and the implications ofstrict liability means that an athlete isheld responsible for whatever is in theirbody irrespective of how it got there.Therefore, athletes who compete underthe WADA code should be extremelycautious about using supplements andalways work with a qualified professionalon risk minimisation of supplement use.

BJSM SUPPLEMENT SERIESThere are many reviews on supplementa-tion in athletes, some of which are verygood. Our aim is not to replicate these,but to give a series of very brief overviews,some of which will be by experts in thefield. Our main aim is simply to demystifysome of the many supplements on themarket in order to provide a usefulresource for athletes, sport and exerciseenthusiasts, along with allied profes-sionals such as nutritionists, coaches,physiotherapists and doctors. Someresearch citations for each topic (or com-ment on the lack of them) will beprovided for those who wish to investi-gate further. When feasible, practicaladvice will be given about dosage andtiming. Needless to say, this advice will bebased on the best available sources at thetime. (The authors cannot be held respon-sible for the failure of any specific dose toimprove performance, etc.)

This series will cover a range of thesupplements commonly used by athletes.Table 1 provides an example of 102supplements that will be included in theseries. Some of these will be completeproducts, whereas others will be theindividual substances that make up themany poly-ingredient supplements on themarket. Our commentaries are planned tobe set out in alphabetical order. However,

we will make allowances for commentson any supplement that has recentlybecome a ‘‘hot topic’’ rather than waitfor its place some time down the line.Articles will be cross-referenced to allowfor those supplements that are popularlyknown to athletes by more than onename.

With such a vast range of supplementsand ingredients marketed for athletes, wesimply will not be able to cover them alland, for some, it will just be a briefmention or cross-reference. Furthermore,owing to time and space constraints,these articles will deal specifically withthe effects of these supplements onexercise and sport-related health andperformance issues rather than generalhealth or clinical issues.

Competing interests: None.

Provenance and peer review: Commissioned; notexternally peer reviewed.

Accepted 9 July 2009

Br J Sports Med 2009;43:728–729.doi:10.1136/bjsm.2009.063941

Table 1 An example of most supplements that will be covered in the BJSM supplement series

Alpha-ketoglutarateAmino acidsAndrostenedioneAntioxidantsArnicaBee pollenBoronBuffersCaffeineCalciumCarbohydrateCarnitineChinese medicinesCholine bitartrate/acetylcholineChondroitinChromium picolinateCissus quadrangularisCitrullineCLACoenzyme Q10

ColostrumCopperCreatineCurcuminCytochrome CDHEADihydroxyacetoneDimethylglycineEchinaceaElectrolytesEphedra (Ma Huang)Fatty acids & MCTsFerulic acidFish oilsFlavonoidsFolic acidGamma-butyrolactone(GBL)Gamma-oryzanolGamma-aminobutyricacidGarlic

Gingko bilobaGinsengGlandularsGlucosamineGlutamineGlutathioneGlycerolGreen teaGuaranaHMBHydroxycutInosineInositolIronKIC (alpha-ketoisocaproate)LecithinLeptinLinoleic acidMagnesiumMelanine

MelatoninMineralsMSGMSMN-AcetylcysteineNitric oxidestimulatorsOctacosanolOmega 3, 6, 9 fattyacidsOrnithineOxygenated watersPhlogenzymPhosphate saltsPhosphatidylserinePlant sterolsPolylactatePre/probioticsProhormonesProteinPycnogenolPyruvate

QuercetinRhodiola roseaRiboseRoyal jellySeleniumSpirulinaSuccinateSugars &sweetenersTheobromineTheophyllineThyroxineVanadiumVandyl sulphateVitaminsWheat germ oilWobenzymYohimbineYuccaZincZMA

CLA, Conjugated Linoleic Acid; DHEA, Dehydroepiandrosterone; Fatty acids & MCTs, Medium Chain Triglycerides; GBL,Gamma-butyrolactone; HMB, Beta-hydroxy-beta-methyl-butyrate; MSG, Monosodium Glutamate; MSM, Methyl-sulphonyl-methane; ZMA, Zinc Magnesium Aspartate.

Further reading

c Geyer H, Parr MK, Mareck U, et al.Analysis of non-hormonal nutritionalsupplements for anabolic-androgenicsteroids: results of an internationalstudy. Int J Sports Med 2004;25:124–9.

c Geyer H, Mareck U, Kohler K, et al.Cross contaminations of vitamin- andmineral-tablets with metandienone andstanozolol. In: Schanzer W, Geyer H,Gotzmann A, et al, eds. RecentAdvances in Doping Analysis (14).Koln: Sportverlag Strauß, 2006:11.

c Geyer H, Parr MK, Koehler K, et al.Nutritional supplements cross-contaminated and faked with dopingsubstances. J Mass Spectrom2008;43:892–902.

c Maughan RJ, King DS, Lea T. Dietarysupplements. J Sports Sci2004;22:95–113.

c Maughan RJ. Contamination of dietarysupplements and positive drug tests insport. J Sports Sci 2005;23:883–9.

Editorial

Br J Sports Med September 2009 Vol 43 No 10 729

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Part 1ergogenic aids for health and performancesupplements, sports nutrition foods and

Z of supplements: dietary−BJSM reviews: A

Louise M Burke, Lindy M Castell and Samantha J Stear

doi: 10.1136/bjsm.2009.0639412009 43: 728-729 Br J Sports Med 

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