NUTRITION
IN TOP ATHLETESNUTRITIONAL
SUPPLEMENTS:
GUIDELINES FOR ATHLETES
Fabio Pigozzi
Italy
Nutritional supplements are
often used by athletes in an effort to optimize their performance.
Nutritional ergogenic aids are taken to increase muscle strength and
mass, endurance capacity, to achieve a faster recovery as well as to
support the immune system to cope with illness and infections.
New
substances claimed to have ergogenic aids continue to appear on the
market, however often these claims are not based on solid scientific
avidence. In is paramount, therefore, to define the substances that
actually provide benefits to athlete´s performance and
clarify the rationale for their use.
One of the most
used ergogeinc aids is creatine, which has been largely proved to
positively affect performance in disciplines characterized by repeated
high intensity exercise. In addition to its affect on muscle
energetics, creatine has been recently suggested to influence protein
balance. Moreover, creatine has been also suggested to influence post
exercise muscle glycogen resynthesis.
Oral bicarbonate
supplementation is likely to produce advantages during exercises where
acidosis constitutes a limit factor to performance. Caffeine
supplementation is proved to be ergogenic in various circumstances,
hover the meachanism leading to these benefits remain to be
definitively established. Ho note, the positive effect of caffeine on
performance can be achived even at doses resulting in urinary levels
below the maximal level allowed by the IOC. Another methylxantine, such
as theophyline, has been also proposed to have ergogenic properties.
Hydorxymethylbutyrate
has been proposed to induce net protein accretion, however the amount
of data available does not allow to make a final statement. Along the
same line, individual aminoacids are also largely used by athletes but
the rational for their use cannot be totally justified. Antioxidants
have been suggested to reduce oxidative damage induced to tissue as a
consequence of exercise, but, again, the evidence is not conclusive.
Supplementation with bovine colostrum is sometime used by either
endurance or strength athlets evend though the evidence justifying its
use is yet inconclusive.
Finally, oral ribose
supplementation is used by some athletes to increase intermittent
exercise performance and it has been suggested to increase muscle post
exercise ATP resynthesis, however recent scientific evidence has not
provided support to these claims. In conclusion, although many
substances are based on reasonable claims the recommendation for their
use by the athletes should be always supported by scientific evidence
regarding their effect and safety.
