01.07.2017

Dietary supplementation

Sport foods and food supplements

Most athletes consider supplements an important and often a magical factor helping them to achieve success in sport. Scientists, on the other hand, are sceptical about them – they do not think that supplements enhance physical efficiency and emphasize that physical efficiency depends on many factors, among them talent, training, sport equipment, diet and the mental predisposition of each athlete. They also emphasize that all that many supplements do is produce the “placebo effect”.

Increased physical effort, which accompanies sport practice, requires more energy and many nutritional ingredients. However, scientific research shows that a properly prepared diet based on natural products is sufficient to provide increased energy and all necessary nutritional ingredients. Therefore a question arises whether athletes should use supplements. The answer is positive – professional athletes should take supplements, particularly when they are in intensive training.

Since an athlete’s health is always most important, only supplements, which are safe, effective and permitted in sport should be used. Supplements for athletes are a group of products, which have not been analysed thoroughly with respect to their side effects and therefore they should be used carefully and moderately. Today there are many products available for physically active people whose effects have not been confirmed with solid scientific study and therefore their effectiveness is questionable. Furthermore, supplements can contain substances, which are prohibited in sport and their use carries the risk of disqualification.

The Australian Institute of Sport has developed a Sports Supplement Programme in which supplements are classified into four groups according to their effectiveness and safety:

  • Group A –     supplements and substances supported for use by athletes provide a useful and timely source of energy and nutrients in the athlete’s diet, or have been shown in scientific trials to benefit performance, when used according to a specific protocol in a specific situation in sport. This group includes sports gels and sports bars, liquid meal supplements, multivitamins and minerals, antioxidant vitamins C and E, calcium supplement, iron supplement, caffeine, creatinine, bicarbonate or citrate and vitamin D.
  • Group B –     supplements recommended for athletes although requiring further research since presently available results do not provide sufficient proof of their effectiveness. This group includes: glutamine, glucosamine, HMB (ß-hydroxybutyrate), ß-alanine, colostrum, probiotics, ribose, melatonin
  • Group C –    supplements which have not been proven to provide a definite enhancement of sports performance. This group includes: branched chain amino acids, carnitine, chromium picolinate, inosine, coenzyme Q10, nitric oxide, cytochrome C, gamma-oryzanol and ferulic acid, pyruvate, ZMA (zinc, magnesium and B6), cordyceps, Rhodiola Rosea, ginseng, oxygenated water.
  • Group D –    supplements which are banned or are at high risk of being contaminated with substances that could lead to a positive drug test. This group includes: andrestenedione, 19-norandrostenediol DHEA, 19-norandrestenediol, ephedra, strychnine, Tribulus terrestris and other herbal testosterone supplements enhancing the growth of free testosterone in blood, and glycerol.

It must be pointed out that the list of sports foods and supplements in each group is not constant and changes with the progress of scientific research. A valid list of supplements in each group can be found on the website of the Australian Institute of Sport (http://www.ausport.gov.au/ais/).

Professional athletes should use supplements from Group A since these are products particularly useful in achieving nutritional aims and optimal physical efficiency, even when the diet is correctly balanced. The supplements are used mainly to supplement energy reserves in the body, support regeneration processes and help maintain a properly hydrated body. However, it must be pointed out that the use of supplements, even those belonging to Group A, carries the risk of a positive doping test.

Whenever athletes use supplements, they should remember about the individual body response to them since some substances, which have proven effective for some individuals, may prove ineffective or even harmful for others. Sodium bicarbonate is a notable example. Besides, supplementation with nutritional ingredients (e.g. vitamins or minerals) should only be resorted to in exceptional situations (e.g. by people wishing to reduce their body mass or by athletes in intense training) and supplements should be used only in quantities, which do not exceed maximum tolerated levels of consumption. Higher, therapeutic doses of supplements should be used under the control of a physician and in situations when it is necessary, e.g. if their deficits have been found earlier.

It must be strongly emphasized that the health and physical efficiency of athletes can be greatly enhanced if their diet is natural and correctly composed. Any energy enhancing supplements improve physical efficiency to a negligible extent only.

Fig.1. The effect of a natural diet, sports foods and ergogenic supplements on an athlete’s physical efficiency (after the Australian Institute of Sport, 2009) 

Before athletes use any supplements, they should first of all ensure that what they eat is good for them (safer, healthier and cheaper). Any supplements (mainly from Group A) should only supplement their diet when they are in intense training, never the other way round.

Author: Dr Jadwiga Malczewska-Lenczowska

Literature:

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