Dietary supplements and team-sport performance

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The below may be of interest:

Dietary supplements and team-sport performance.

_Sports Med._ (javascript:AL_get(this, 'jour', 'Sports Med.') 2010 Dec

1;40(12):995-1017. doi: 10.2165/11536870-000000000-00000.

_Bishop D_ (http://www.ncbi.nlm.nih.gov/pubmed?term= " Bishop%20D " [Author]) .

Abstract

A well designed diet is the foundation upon which optimal training and

performance can be developed. However, as long as competitive sports have

existed, athletes have attempted to improve their performance by ingesting a

variety of substances. This practice has given rise to a multi-billion-dollar

industry that aggressively markets its products as performance enhancing,

often without objective, scientific evidence to support such claims.

While a

number of excellent reviews have evaluated the performance-enhancing

effects of most dietary supplements, less attention has been paid to the

performance-enhancing claims of dietary supplements in the context of

team-sport

performance. Dietary supplements that enhance some types of athletic

performance may not necessarily enhance team-sport performance (and vice

versa).

Thus, the first aim of this review is to critically evaluate the ergogenic

value of the most common dietary supplements used by team-sport athletes.

The term dietary supplements will be used in this review and is defined as

any product taken by the mouth, in addition to common foods, that has been

proposed to have a performance-enhancing effect; this review will only

discuss substances that are not currently banned by the World Anti-Doping

Agency.

Evidence is emerging to support the performance-enhancing claims of some,

but not all, dietary supplements that have been proposed to improve

team-sport-related performance. For example, there is good evidence that

caffeine

can improve single-sprint performance, while caffeine, creatine and sodium

bicarbonate ingestion have all been demonstrated to improve multiple-sprint

performance. The evidence is not so strong for the performance-enhancing

benefits of β-alanine or colostrum.

Current evidence does not support the

ingestion of ribose, branched-chain amino acids or β-hydroxy-β

-methylbutyrate, especially in well trained athletes. More research on the

performance-enhancing effects of the dietary supplements highlighted in this

review needs

to be conducted using team-sport athletes and using team-sport-relevant

testing (e.g. single- and multiple-sprint performance). It should also be

considered that there is no guarantee that dietary supplements that improve

isolated performance (i.e. single-sprint or jump performance) will remain

effective in the context of a team-sport match. Thus, more research is also

required to investigate the effects of dietary supplements on simulated or

actual team-sport performance.

A second aim of this review was to investigate

any health issues associated with the ingestion of the more commonly

promoted dietary supplements. While most of the supplements described in the

review appear safe when using the recommended dose, the effects of higher doses

(as often taken by athletes) on indices of health remain unknown, and

further research is warranted. Finally, anecdotal reports suggest that

team-sport athletes often ingest more than one dietary supplement and very

little

is known about the potential adverse effects of ingesting multiple

supplements. Supplements that have been demonstrated to be safe and efficacious

when

ingested on their own may have adverse effects when combined with other

supplements. More research is required to investigate the effects of

ingesting multiple supplements (both on performance and health).

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Carruthers

Wakefield, UK