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  • 1. Nutritional supplements as ergogenic aids Active patients may ask if they should use various nutritional supplements to enhance their athletic performance. Are these supplements effective? Or are they just dangerous? N utritional supplements and their use by athletes as ergo- genic, or performance-enhanc- P. GUNNAR BROLINSON, DO, Discipline Chair, Sports Medicine, Edward Via Virginia terious effects. Be aware that athletes who try commercial supplements may want to use ing, aids have been getting a lot Coilege of Osteopathic additional products and could of media attention in recent Medicine, and Head Team eventually use a dangerous sub- years. Professional athletes are Physician, Virginia Polytechnic institute, Blacksburg; Team stance. To prevent serious health not the only persons using ergo- threats, communicate openly Physician, US Ski Team. genic aids, however. Recreational with athletically oriented pa- athletes, or even those who just NANCY CLARK, MS, RD, tients, while cautioning them work out regularly at health Director, Nutrition Services, about disproven or dangerous clubs, also use these supple- SportsMedioine Associates, supplements. ments. It is thus important to Brookline, Mass; author, Naricy Clarks Sports Nutrition OVERSIGHT FALLS SHORT carefully evaluate the claims that Guidebook 3rd ed, 2003; are made about supplements and and nutrition consultant, The Dietary Supplement Health to educate patients to do the Boston Coilege Athletes. and Education Act of 1994 is the same. basis on which companies can Counseling patients to culti- MARKS.JUHN,DO, make health claims about their Clinical Assistant Professor, vate lifelong, healthy dietary products.^ This legislation estab- Department of Family Medicine, habits is the most important in- lished a definition of dietary sup- University of Washington School tervention because a nutritional- of Medicine, Seattle; Team plements and dietary ingredi- ly sound eating plan is safer and Physician, University of ents; a framework to guaranteemore effective than taking sup- Washington Ice Hockey; and safety; guidelines for the litera-plements. Strategies include rec- Attending Physician, Hall Health ture available where the prod- ommending a diet adequate in Center, University of Washington. ucts are sold; the use of claimsprotein, carbohydrate, and fat and support statements on prod- MATTHEW D. VUKOVICH, PhD,and timing nutrient intake for Assistant Professor, Department of uct labels; a requirement for la-optimal use by the body before, Health, Physical Education, and beling of ingredients and nu-during, and after exercise. Ac- Recreation, South Dakota State tritional value; and authority forcording to the American Dietetic University, Brookings. the FDA to create standards ofAssociation and the American good manufacturing practices.College of Sports Medicine on nutrition and ath- While this document was a good beginning, itletic performance, if adequate energy can be ob- did not go far enough, and it opened the door fortained through the diet, vitamin and mineral sup- supplement manufacturers to bypass the rigorousplements should not be necessary ^ Vitamin and testing that drugs must go through conventional-mineral supplements may be important, however, ly In addition, many products were classified asif athletes limit energy intake, eliminate certain dietary supplements for no apparent reason,food groups from their diet, take extreme mea- when they really should have been classified assures to lose weight, or consume a diet high in car- drugs. Androstenedione; a precursor to testos-bohydrates but low in micronutrients. terone, is one well-known example. When patients inquire about other nutritional New dietary ingredients in supplements do notsupplements, you should explain the most recent have to adhere to a clearly defined set of safetyresearch and inform them of any potentially dele- standards. Not all products include safety informa- PATiENT CARE/JANUARY 2004 37
  • 2. Nutritional supplements tion on the label, an oversight that may prove icant ergogenic effect on the results of resistance dangerous to some persons because no regulation training. exists specifying the information required. Most Potential risks Side effects of androstenedione reports of adverse effects attributable to dietary supplementation may be similar to those of tes- supplement use are not investigated, hindering tosterone administration and could include de- assessment of the effect a supplement may have creased HDL-cholesterol, increased aggressive on consumer health. Unfortunately federal laws behavior, benign prostate hyperplasia, heart dis- and government agencies do little to protect con- ease, gynecomastia, and acne. sumers against misleading or inaccurate claims about dietary supplements or help the public Branched chain amino acids (isoleucine, make informed decisions about the safety of leucine, and valine) these products. According to the US General Several amino acids have functions unique to Accounting Office, the likelihood that unsafe specific organs. It has been suggested that they products are made available to consumers is may also have use as ergogenic aids. increased by several weaknesses in the regulatory Basis for supplementation Low levels of system.^ branched chain amino acids (BCAAs) promote fatigue. BCAAs may provide an energy source THE FACTS ABOUT POPULAR SUPPLEMENTS because they are metabolized by muscle. The It is important to consider both the safety and leucine metabolite beta-hydroxy-beta-methylbu- efficacy of dietary supplements. In many cases tyrate (HMB) is believed to prevent muscle catab- (perhaps up to 90%), the product is not effective. olism, facilitate muscle repair after exercise, When deciding if a supplement is worth using, decrease body fat, and increase lean muscle mass. ask: /acf Little or no improvement in performance • Is the product legal? was seen in several studies of long-distance run- • Does evidence in peer-reviewed journals sup- ners using both short- and long-term supplemen- port or refute the manufacturers claims about its tation. Studies have shovm that oxidation of product? BCAAs increases 2- to 3-fold during exercise, • What are the potential side effects, if any? while oxidation of fat and glucose increases 10- to • What is the physiologic theory that supports 20-fold.^ In addition, consumption of carbohy- the products supposed mechanism of action? drates prevents an increase in BCAA oxidation. BCAAs thus do not appear to act as fuel during Androstenedione exercise of light, moderate, or heavy intensity This androgen precursor has weak anabolic activ- Limited information is available about the ity, although little is known about its effect on metabolism of HMB and its mechanism of action. weight loss and muscle mass increase. Potential risks Although HMB appears to have Basis for supplementation It is believed that ergogenic potential, much of the research about oral doses of androstenedione mimic the effects the effects of HMB has been done in animals.* of supraphysiologic doses of parenterally admin- istered testosterone. The dosage of androstene- Caffeine dione recommended by manufacturers is 100 to This stimulant is used to enhance mental alert- 300 mg/d, although many athletes may take as ness and increase reaction time. It is also used to much as 500 to 1200 mg/d. increase stamina. The mechanism for the fact One study of 30 healthy men who were ergogenic effect of caffeine remains somewhat given 300 mg/d of androstenedione found ele- inconclusive in humans, though rat studies clear- vated levels of serum estrone, which suggested ly show that caffeine inhibits adenosine recep- that most of the supplement was converted to tors, which are ubiquitous in the human body^ estrogen."* This study found no effect of andro- Basis for supplementation The goal of en- stenedione supplementation on serum testos- durance athletes is to spare muscle glycogen until terone levels and failed to demonstrate a signif- it becomes absolutely necessary to use it. Caffeine 38 PATIENT CARE / JANUARY 2004
  • 3. Nutritional supplements spares carbohydrates while increasing fat break- that supply adequate nutrition. Sports drinks down and fat oxidation. The US Olympic may be a source of easily digestible carbohydrates Committee (USOC) defines a positive test for caf- but sports drinks alone provide inadequate calo- feine as a urine concentration of greater than 12 ries and carbohydrates. The athlete should con- mcg/mL. sume additional carbohydrates from such foods Fact A recent report suggests that athletes will as juice, fruit, bagels, and energy bars.not incur detrimental fluid electrolyte imbalance Carbohydrate loading is a technique wherebyif they consume caffeinated beverages in moder- athletes consume a high-carbohydrate diet for 7ation.^ The strength of evidence of caffeines er- to 10 days prior to an endurance event whilegogenic potential is strong, particularly in aerobic tapering their exercise. Ideally the calories fromactivity"" A study of well-trained male triath- carbohydrates should come from grains, fruits,letes and cyclists who consumed 3 different doses vegetables, and low-fat dairy foods, although sug-of caffeine [154 mg (2.1 mg/kg), 230 mg (3.2 ars also accomplish the same, and 328 mg (4.5 mg/kg)] in a 1-hour Fact Although sports drinks are effective, it iscycling time trial showed that even in the lowest important that athletes experiment vdth them indose, there was improvement in performance.^ practice prior to use in competition because theyInterestingly the highest dose was no more effi- may cause GI distress or sluggishness.cacious than the middle one, indicating a possi-ble saturation effect of caffeine as an ergogenic Creatineaid. Urinary concentrations of caffeine in samples This nitrogenous amino acid appears to play acollected 5 minutes postexercise did not reach role in rapid energy production and may benefitany higher than 2.5 mcg/mL. This is well below athletes competing in speed or power sports. Itthe disqualification limits imposed by the has not been proven effective in weight-bearingInternational Olympic Committee (12 mcg/mL) activities such as running or swimming, howev-and the National Collegiate Athletic Admin- er, and it is doubtful that creatine will benefit anistration (15 mcg/mL). However, urinary mea- endurance athlete.surements of caffeine can be quite inaccurate. Basis for supplementation Creatine can com- bine with phosphate in the muscles to replenishCarbohydrates the store of phosphocreatine, thus increasingThe use of sports drinks and techniques such as turnover of adenosine triphosphate during exer-so-called carbohydrate loading is believed to cise involving short, intermittent bursts of anaer-thwart premature fatigue ("hitting the wall"). obic activity Supplementation protocols typicallyBasis for supplementation When a workout begin vnxh a loading dosage of 20 g/d for 5 daysperiod lasts longer than 60 minutes, sports drinks followed by maintenance dosages of 2 g/d.provide muscle fuel and facilitate the absorption Fact It is too broad a generalization to state thatof water and glucose from the small intestine. creatine exerts an ergogenic effect in all types ofSports beverages also slow the depletion of mus- speed or power sports. More research is neededcle glycogen during exercise, which may increase for a variety of both nonaerobic and aerobic activ-performance time. The electrolytes in sports ities. People taking creatine supplements initiallydrinks enhance fluid absorption, which is benefi- gain weight very rapidly due to water retention,cial when exercising in conditions of high heat and the extra weight often remains. Controversyand humidity exists regarding whether this weight is retained Postexercise carbohydrates are needed to re- because muscle mass has been added or if it isstore depleted glycogen. Sports beverages can only the initial water weight.provide carbohydrates and water for athletes fol-lowing exercise, when they are less likely to eat Dehydroepiandrosterone (DHEA)appropriately, to eat enough, or to have access to A steroid secreted by the adrenal cortex, DHEA isnutritious food choices. Athletes who compete at not recommended for use in the general populationall-day events may have difficulty obtaining foods as a nutritional supplement. Continued on page il PATIENT CARE / JANUARY 2004 39
  • 4. Nutritional supplementsBasis for supplementation DHEA stabilizes from 10 adverse events, and permanent disabilitybody weight and enhances body fat metabolism. It resulted from 13 events .^also decreases cholesterol, stabilizes blood glucoselevels, and has andoxidant properties. Manu- Gamma-hydroxybutyrate (GHB)facturer-recommended dosages of the synthetic Little evidence exists to substantiate claims aboutforms that are sold as supplements are 30 to 90 possible benefits of GHB. This compound is dan-mg/d. DHEA is believed to maximize response to gerous, addictive, and illegal.resistance training by increasing strength and Basis for supplementation GHB is promoted asmuscle mass. both a sleep aid and an ergogenic aid. It is be-/art Studies have shown that DHEA is ineffec- lieved to promote muscle building and fat bum-tive in maximizing resistance training response. ^^ ing by stimulating the production of growth hor-Limited data of DHEA supplementation are avail- mone in the pituitary in humans, and most studies have focused Fact A recent study describes vwthdrawal fromon the effects of supplementation in older per- GHB as an escalating crisis in US emergencysons, because blood DHEA levels decline with departments.^* It has a reputation as a so-calledage. In women, it can impair glucose tolerance "party drug" that has been implicated in sexualand decrease insulin sensitivity and decrease assaults. Of 8 GHB withdrawal cases described inHDL cholesterol. the study 5 persons had used GHB as a body-Potential nsks Adverse effects associated with building supplement. The federal governmentDHEA supplementation in humans are unknown, banned the sale of GHB in April 2000.but may include facial hair growth in females,hepatomegaly, and peroxisome proliferation. Gingko biloba Gingko biloba increases blood fiow to the brain Ephedra sinica (Ma huang) and improves blood flow through major bloodThis alkaloid stimulates the sympathetic nervous vessels and capillaries. It is also has a powerfulsystem and increases the metabolic rate by acti- antioxidant effect.vating the adrenergic receptor sites in the heart Basis for supplementation Gingko is behevedand lungs. The USOC, International Olympic to improve concentration in sports that requireCommittee, and the National Collegiate Athletic athletes to maintain mental focus under condi-Association classify ephedra sinica as a banned tions of competitive stress, such as gymnastics,substance, and the FDA banned it in December tennis, and diving. The average dose is 120 to 2402003. mg/d, taken in 2 or 3 divided doses.Basis for supplementation Athletes use ephed- Fact Limited data are available about the effec-ra to promote weight loss and increase energy It tiveness of gingko as an athletic supplement. Apromotes the release of fatty acids stored in fat placebo effect may be responsible for its per-cells and the burning of fat for energy (the ther- ceived efficacymogenic effect). Ephedra also increases the con- Potential risks Gingko is associated with raretractile strength of muscle fibers, allowing weight incidences of stomach upset, headaches, and al-lifters and body builders to work out more in- lergic dermatitis. It may interact with anticoagu-tensely while using heavier weights. lant drugs such as aspirin./acf Ephedra alkaloids have no demonstratedbenefit as a dietary supplement or in athletes be- Ginsengcause they do not provide essential nutrition or Siberian ginseng has a chemical composition dif-have an ergogenic effect. An independent review ferent from that of the better knovm and more ex-of adverse-effect reports about the use of pensive Chinese ginseng. The effect of the 2ephedra-containing dietary supplements found herbs is similar, though.that use of these supplements caused adverse Basis for supplementation Ginseng is believedevents that included hypertension, palpitations to increase mental alertness and reaction time inor tachycardia, stroke, or seizures. Death resulted sports requiring increased mental alertness and PATiENT CARE / JANUARY 2004 41
  • 5. Nutritional supplements quick reaction time for prolonged periods such as an essential mineral, is important for the metab- hockey and football. The average dosages are 1 to olism of glucose and lipids. 2 g/d of Asian ginseng root or 0.6 to 3 g/d of Basis for supplementation Chromium and Siberian ginseng root. vanadium are believed to potentiate insulin ac- fact Ginsengs perceived effects may be scien- tioh and stimulate cellular amino acid uptake. tifically sound or a result of a placebo effect. A Boron is believed to build muscle mass because it small study suggests that prolonged supplemen- has been shown to increase testosterone levels in tation with ginseng has no ergogenic benefits.^ postmenopausal women. Potential risks Although ginseng use is not Chromium, which is considered an essential known to be associated with any adverse effects, it mineral, has an estimated safe and adequate is a stimulant. It should not be used in persons with dietary intake of 50 to 200 mcg/d. The most com- cardiac disorders, hypertensive or hypotensive dis- mon commercially available form of chromium is orders, or diabetes. Those taking corticosteroid or chromium picolinate. Vanadium is not considered antipsychotic therapy should also avoid ginseng. an essential mineral. An intake of approximately 10 mcg/d of vanadium is considered sufficient. But Iron not enough evidence exists to establish a suggest- A decrease in hemoglobin impairs oxygen deliv- ed boron intake for humans, although approxi- ery to the muscles and is deleterious to athletic mately 1 mg/d is the estimated recommendation. performance.^^ Fact Although one study reported that chromi- Basis for supplementation Iron status is often um picolinate increased lean tissue in young men negatively affected in those who exercise regularly who participated in a resistance training pro- Female athletes who menstruate may have an gram, the results were not confirmed in 4 addi- increased incidence of iron depletion because they tional trials. ^ have a net negative iron balance at the outset. Potential risks Anemia is a potential adverse ef- Fact The impact of iron supplementation on ex- fect associated with chromium supplementation. ercise performance requires further clarification, although limited data would imply an improve- Protein supplements ment in endurance performance and a decreased Despite the current protein craze, no evidence exists that any one particular protein supplement reliance on glucose as an oxidative substrate. Even in an athlete with low-normal levels of iron andimproves athletic performance. Most athletes need more carbohydrates not more protein. ferritin, iron supplementation is sometimes tried to prevent fatigue.^^ Basis for supplementation Many athletes be- To halt iron deficiency from developing in lieve that protein supplements increase strength, power, muscle growth, and work capacity. those at greatest risk, such as female athletes, dis- tance runners, and vegetarian athletes, dietaryf^ct A nonathlete requires 0.8 g/kg/d of pro- measures may be implemented. The dietary ref- tein, and a growing athlete may require 1.5 erence intake (DRl) of iron for men aged older g/kg/d. Strength athletes may require slightly than 18 years is 10 mg/d; for women 19 to 50 more protein during the muscle building phase. Use of protein powders by those who are non- years of age it is 18 mg/d. The upper limit of safe- ty is 45 mg/d for those aged 14 years and olderdeficient in protein shows no beneficial effect in unless prescribed by a clinician. boosting strength, power, muscle growth, and work capacity In addition, the labeling of these Potential risks Excess iron from dietary supple- ments can cause nausea, vomiting, and diarrhea products is often inadequate in terms of what and may be associated with an increased risk ofingredients they actually contain. heart disease and certain cancers. Potential risks Little evidence exists regarding safety concerns, and most of this evidence is Minerals gathered in rats. Side effects could include dehy- The minerals chromium, boron, and vanadium dration, Gl disturbances, gout, hepatic and renal are believed to increase muscle mass. Chromium, toxicity, and increased risk of osteoporosis. The 42 PATIENT CARE / JANUARY 2004
  • 6. Nutritional supplementsimmediate concern is that too much protein dis- Antioxidant vitaminsplaces carbohydrate from the diet, and this con- Antioxidants may reduce muscle soreness, andtributes to reduced glycogen stores. results of studies look promising. Basis for supplementation Beta carotene, ascor-Vitamins bic acid (vitamin C), and vitamin E are believedThe vitamin requirements of athletes can be ade- to neutralize free radicals and reduce exercise-quately met through a properly varied diet. induced muscle damage and soreness. The USOCBasis for supplementation Physical activity guidelines recommend 3 to 20 mg/d of betamakes additional demands on the metabolic carotene, 250 to 1000 mg/d of vitamin C, and 40pathways dependent on vitamins such as thi- to 150 IU/d of vitamin E.amine (vitamin Bj), riboflavin (vitamin Bj), and Fact No enhancement of athletic performancepyridoxine (vitamin Bg).^^Most athletes eat large has been attributed to antioxidant vitamins at seaquantities of food and are able to meet their vita- level, although vitamin E may have ergogenicmin requirements through cereals, enriched properties at higher altitudes.grains, and lean meats. Potential risks Excess ascorbic acid intake canFact Thiamine is found in pork, legumes, and case nausea, stomach cramps, and diarrhea. Ex-yeast. Good sources of riboflavin are eggs, milk, cess vitamin E supplementation is associated withmilk products, and lean meats. Pyridoxine is interference with the clotting action of phytona-found in plant foods, including cereals and dione (vitamin K) and with augmentatidn of thebrown rice, and meats, particularly tuna and effect of anticlotting drugs, which increases thechicken. The DRI for pyridoxine is 1.3 mg/d for risk of hemorrhage. Dadults and should not exceed 100 mg/d. The DRI PRODUCED BY CHARLOTTE LoBUONOfor thiamine is 1.2 mg/d for adult men and 1.2mg/d for adult women. The DRI for riboflavin is 1.1 www.patientcareonline.commg/d for adult women, 1.3 mg/d for adult men. Visit our Web site forPotential risks Adverse effects associated vnthexcess pyridoxine supplementation include de- > DHEA and stresspression, fatigue, headaches, and the potential for > Food as an ergogenic aid: One on One withneurotoxicity Excess thiamine intake rarely caus- Nancy Clark, iVIS, RDes toxicity, but adverse effects may include weak- > The evidence againstness, headaches, insomnia, and irritability The ephedratoxic effects of excess riboflavin are unknowTi.REFERENCES1. Position of the American Dietetic Association, Dieticians of Canada, and the 10. Pasman WJ. van Baak MA, Jeukendrup AE, et al. The effect of different American College of Sports Medicine: Nutrition and athletic performance. dosages of caffeine on endurance performance time, int J Sports Med J Am Diet Assoa 2000;100:15A3-1556. 1995:16:225-230.2. US Food and Dnjg Administration Center for Food Safety and Applied 11. Kovacs EM, Stegen JHCH, Brouns F, Effect of caffeinated drinks on sub- Nutrition. Dietary Supplement Health and Education Act of 1 QSi. Available at: strate metabolism, caffeine excretion, and performance. J Appi Physioi. Accessed Febaiary 20, 2001. 1998:85:709-715.3. US General Accounting Office. Improvements needed in overseeing the 12. Clarkson PM, Rawson ES. Nutrition supplements to inorease muscle mass. . safety of dietary supplements and functional foods. Available at http:// Crit Rev Food Sd Nutr. 1999:39:317-328. Accessed March 20, 2001. 13. Halier CA, Benowitz NL. Adverse cardiovascular and central nervous sys-4. King DS, Sharp RL, Vukovich MD, et al. Effect of oral androstenedione on tem events associated with dietary supplements containing ephedra alka- serum testosterone and adaptations to resistance training in young men: a loids. W & g / . 7 M e d 2000:343:1833-1838. randomized control trial. JAMA. 1999:281:2020-2028. 14. Dyer JE, Roth B, Hyma BA. Gamma-hydroxybutyrate withdrawal syndrome.5. Wagenmakers AJ. Amino acid supplements to improve athletic perfor- Anr) EmergMed 2001:37:147-153. mance. CurrOpin Clin NutrMetab Care. 1999:2:539-544. 15. EngelsHJ. Kolokouri I, CieslaTJ 2nd, etal. Effects of gingseng supplemen-6. Nissen S, Sharp R, Ray M, et al. Effect cf leucine metabolite beta-hydroxy- tation on supramaximal exercise performance and short-term recovery. beta-methylbutyrate on muscle metabolism during resistance-exercise J Strength Cond Res. 2001:15:290-295. training. J Appi Physioi. 1996:81:2095-2104. 16. Beard J, Tobin B. Iron status and exercise. Am J din Nutr. 2000:727. Fredholm BB, Battig K, Holmen J, et al. Aotions of caffeine in the brain with C2 suppri:594S-597S. special reference to factors that contribute to its widespread use. 17. Brutsaert TD, Hernandez-Cordero S, Rivera J, et al. Iron supplementation Pharmacoi Rev. 1999:51:83-133. improves progressive fatigue resistance during dynamic knee extensor8. Armstrong LE. Caffeine, body-fluid eleotrolyte balance, and exercise per- exercise in iron-depleted nonanemic women. Am J din Nutr. 2003:77: formance. IntJ Sport Nutr Exerc Metab. 2002:12:189-206. 441-448.9. Graham TE. Caffeine and exercise: metabolism, endurance and perfor- 18. Manore M M . Effect of physical activity on thiamine, riboflavin, and vitamin mance. Sports Med. 2001:31:785-807. B-6 requirements. Am J din Nutr. 2000:72C2 suppl]:598S-606S. PATIENT CARE / JANUARY 2004 45