A Look at Sports Nutrition Supplements, Their Ingredients and Evidence

1. NMR News: Volume 2, Issue 7, October 2009
A Look at Sports Nutrition Supplements: Their
Ingredients & Evidence
By: Charles Spielholz, Ph.D.
October 2009
There is a wide range of products on the market mild stimulant of known mechanism, found in coffee
known as sports supplements. The purpose of a sports and tea. Sugar is the most common molecule burned
supplement is to help the user be more energetic and by aerobic cells for energy production.
more muscular. Such products may also claim to aid
in the loss of fat and to improve recovery after Glucuronolactone, a metabolite of the sugar glucose,
strenuous exertion. In addition, some products may is included in some energy drinks because some
also claim to improve performance, although preliminary clinical studies indicate that it may
performance enhancing substances are not legal in improve high intensity endurance. However, a clear
professional sports. mechanism, of action for glucuronolactone's
proposed properties has not yet been established. In
In order to accomplish the purposes of a sports addition, few clinical trials have been done using
supplement, manufacturers use specific ingredients glucuronolactone alone. Creatine is included in some
that are supposed to have the desired effects on the sports supplements for reasons similar to that of
body. The ingredients used by manufacturers are glucuronolactone.
quite numerous and varied. No attempt will be made
to cover this wide variety in this short report. Finally, taurine has been shown again in preliminary
However, this report will discuss some of the rational clinical studies, to play a role in changes in the
behind the design of sports supplements and will be uptake of glucose. However, additional studies are
the basis for beginning a discussion on these required before regulatory agencies will allow
products. manufacturers of sports supplements to make claims
that taurine enhances energy in humans.
For providing energy, sports supplements can contain
ingredients such as caffeine, glucuronolactone, tea Energy supplements usually contain a variety of
extracts, sugar, taurine, and/or creatine. Caffeine is a ingredients to support the building of muscle. Such
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2. NMR News: Volume 2, Issue 7, October 2009
ingredients include protein (sometimes in the form of without the advice and supervision of a physician.
whey or similar substances) and amino acids. Amino Hormone and pro-hormone supplements are
acid composition of sports supplements include both dangerous to use by healthy individuals. Hormone
the essential amino acids (those required in the and pro-hormone substances should only be used by
human diet because humans can not synthesize them individuals who have a specific indication, identified
on their own) as well as the non-essential amino by a competent physician. For example,
acids. Although healthy people are able to synthesize Dehydroepiandrosterone (DHEA), which is a
their own non-essential amino acids, these amino precursor hormone to testosterone and is found
acids are added to sports supplements in order to naturally in humans, is purported to increase muscle
boost reserves when demand is high during strenuous mass and decrease fat in humans. Not only is the
exertion. evidence for these effects thin, but DHEA is known
to cause an elevation of blood pressure and to have
In addition to amino acids and protein, sports dangerous interactions with prescription drugs.
supplements can contain vitamins, minerals, fatty
acids, electrolytes and water. All of these substances Currently, sports supplements are a mixed bag. Some
can be depleted during exercise or related exertion. sports supplements which replace electrolytes, water
Although ingredients such as vitamins and minerals or provide a little extra protein or sugar are safe and
can be obtained from a vitamin supplement, it is may be useful to people who need a quick way to
convenient to have everything that is needed in one replenish low reserves of these important molecules.
source. Such an approach makes it easier to However sports supplements which make claims that
administer and keep tract of what an individual is have not been vigorously proven or contain
using. substances, whose safety has not been clearly shown,
should be used with caution if at all. Such substances
Hormones, or pro-hormones, can also be part of the are only in the early stages of clinical testing;
make up of a sports supplement. Such hormones or additional research is needed to show that the
pro-hormones are generally testosterone or ingredients are indeed effective. As with any
testosterone precursors or molecules with functions supplement, sports supplements should not be used
similar to testosterone. Such ingredients are banned by diabetics, those taking monoamine oxidase
by professional sports organizations worldwide. In (MAO) inhibitors, or who have heart, circulatory or
addition, such supplements should never be taken respiratory issues or who have cancer.
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