DEFINITION

Sports Supplements are used by sportspeople to improve athletic performance. Sports Supplements are also known as dietary ergogenic aids.

DESCRIPTION

Carbohydrate supplementation is generally accepted as a safe and effective means of performance enhancement, used widely by athletes throughout the world. Following is a short summary of some other popular dietary ergogenic aids used by athletes today:
Caffeine is a common drug consumed by people every day, in coffee, tea and cola drinks, as well as chocolate and many non-prescription medications. Caffeine is a 'controlled or restricted drug' in athletic circles as urinary levels greater than 12 ug/mL following competition are considered illegal by the International Olympic Committee. Recent, well-controlled studies have established that moderate doses of caffeine ingested 1 hour prior to exercise can enhance the performance of certain types of endurance exercise, as well as intense exercise lasting 5 - 20 minutes.
The mechanisms for improving performance remain unclear. However, ingesting less than 9 mg per kg of bodyweight will usually result in urinary caffeine levels below the legal limit of 12 mg per mL, and may improve endurance and some short-term performances. It is important to note also that there is great individual variation in response to the effect of caffeine and it may be that some athletes get no ergogenic effect from its use.
Amino acids are an integral part of the structure and functioning of our body and are the basis of the multitude of different dietary proteins we eat each day. In recent years, amino acids have become widely available in supplement form for the purpose of enhancing sporting performance. These are generally sold as one or more individual amino acids with specific proposed roles such as assisting with muscle growth or aiding recovery. In this limited summary, it is impossible to review all of the research regarding amino acid supplementation and its effects on performance. However, current thinking may be summarised by the following points:
- There is little data to support the theory that oral amino acid supplements enhance muscle development through growth hormone release.
- Athletes do appear to have higher requirements for amino acids, and in particular the indispensable amino acids, however it seems likely that most athletes can meet these increased requirements through the diet.
- Branch chain amino acids have been hypothesized to prevent fatigue in the latter stages of prolonged endurance events, however additional research is still required in this area.
- There may be a role for amino acid intake during and immediately after exercise, where a supplement may be more practical than food.
- Foods such as a boiled egg or a glass of skim milk have been demonstrated to provide more amino acids at about 10% of the cost, compared to amino acid tablets.
Creatine is a compound that occurs naturally in meat and is produced in the body from amino acids. It is necessary for the production of creatine phosphate, which couples with ATP to provide immediate energy to exercising muscles. The amount of research focusing on creatine supplementation is steadily growing, and it does appear that creatine loading can be effective in improving the performance of repeated bouts of high-intensity exercise with short recovery time between. Some preliminary studies also suggest that creatine may promote increases in lean body mass during training although further work is required to confirm this.
A recent study did not support any improvement in a single sprint performance following creatine supplementation by elite and highly trained swimmers. Other studies have also failed to show improvements in a single bout of high intensity exercise with creatine supplementation, nor does it appear to enhance endurance performance. Potential side effects of long-term usage, and the specific applications for individual sports are just two areas for consideration.
Bicarbonate loading is a nutritional technique used by athletes performing high intensity anaerobic activity such as an 800m run or a 200m swim. Ingested sodium bicarbonate can buffer lactic acid build up during intense exercise lasting around 2 - 5 minutes. A positive effect has been noted with athletes consuming between 200-300mg per kg of bodyweight of sodium bicarbonate. However, side effects are commonly associated with these dosages, including nausea, vomiting, flatulence, diarrhoea and muscle cramps. Like caffeine, the effect of bicarbonate loading varies considerably between individuals and should be tested out in a training situation prior to use in competition.
Ginseng is a traditional Chinese medicinal herb that has been used for more than 4000 years in the Orient as an `energy booster' and general tonic. In recent times it has been reported to have a number of ergogenic effects on human performance, including improved endurance. Research has identified a number of active ingredients in ginseng, however studies have generally failed to support any performance enhancing effects from the use of ginseng by athletes. Studies are limited somewhat by the difficulties in standardising the composition of ginseng supplements. See the Panax Ginseng and Siberian Ginseng topics.
Phosphate has been studied with respect to its effect on improving VO2 max and increasing anaerobic threshold. Some research shows a possible benefit in acute phosphate supplementation in moderate to high intensity exercise, however results have been variable. It would appear that phosphate has the potential for similar gastrointestinal disturbances to bicarbonate and like bicarbonate, it is likely that any ergogenic effect is subject to individual variation.
Chromium Picolinate has attracted much interest in recent times due to chromium's role in carbohydrate and lipid metabolism, and in glucose homeostasis. It is thought that dietary intakes of chromium may be suboptimal and that physical stress causes increased chromium losses. The claims attributed to this supplement include improving body composition, stabilizing blood glucose and lowering serum cholesterol. To date, however, research looking at all of these areas has failed to consistently support these claims. We await further studies before athletes can be encouraged to add chromium picolinate capsules to their training bags.

For details of banned substances, see the International Olympic Committee Medical Commission's web page: http://www.olympic.org/ioc/e/org/medcom/medcom_intro_e.html. As the list of banned substances is sometimes revised, it is vital that athletes check with their national sporting organisation or the IOC before taking supplements.

PHARMACIST'S ADVICE

1) Ask your Pharmacist for advice about specific supplements.
2) Contact your national sporting body sports for information on banned substances in sport.
3) The individual variation in the effectiveness of supplements can be enormous. Always trial anything new during training first, not before competition.
4) Check for scientific research supporting the safety and use of dietary sports supplements.
5) Remember, nothing takes the place of a healthy diet.

REFERENCE SOURCES

1. Cardwell G. and Comito T. Amino Acid Supplements: an art form or a science?, Sport Health, Vol 13 (1), 34 - 37.
2. International Journal of Sport Nutrition, Volume 6, No. 3 Sep 1996.
3. Sherman M. and Lamb, D. Proceedings of the Gatorade Sports Science Institute Conference on Nutritional Ergogenic Aids, International Journal of Sport Nutrition, Supplement to Volume 5, June 1995.
4. International Journal of Sport Nutrition, Volume 4, No. 2, June 1994.
5. Armsey T. and Green G. Nutrition Supplements, Science vs Hype, The Physician and SportsMedicine Vol 25, No. 6. June 1997.
All information has been compiled by Lorna Garden, leading Sports Dietitian.

NOTES

Supplements approved or recommended for use by Australian Institute of Sport (AIS)athletes:
- Sports drinks, gels and bars and liquid meal supplements.
- Creatine supplements.
- Bicarbonate.
- Caffeine (linited to appropriate and moderate amounts).
- Antioxidants: vitamin C and vitamin E.
- Sick pack (zinc and vitamin C).
- Multivitamin/mineral supplement.
- Iron supplement.
- Calcium supplement.
- Glycerol hyperhydration.

Supplements directly banned by IOC doping rules and not to be used by AIS athletes:
Supplements containing:
- Androstenedione.
- DHEA.
- 19-norandrostenedione and 19-norandrostenediol.
- Tribulus terrestris and other herbal testosterone supplements.
- Ephedra (e.g. Ma-huang).
- Strychnine.
- Guarana products may contain sufficient caffeine to cause an illegal urinary caffeine level.

ORGANISATIONS and SUPPORT GROUPS

All information has been compiled by Lorna Garden, leading Sports Dietitian.
For further information or individual advice, contact Sports Dietitians Australia on (03) 9682 2442 for a referral to your nearest Sports Dietitian.

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