(National Research Council 1989). In other
words, the composition of a sports nutrition sup-
plement would be limited to water, carbohy-
drate, fat, protein and amino acids, vitamins and
minerals. This definition would exclude a wide
variety of nutritional supplements already on the
market (e.g. creatine, carnitine, vanadyl sul-
phate, lipoic acid, etc.). In this case, such a strict
definition is both unwieldly and unrealistic.
In the broadest sense, sports nutrition supple-
ments could include any food, beverage, tablet,
gel, concentrate, powder or potion purported to
be of some value to physically active people.
Both the value and the limitation of adopting a
broad definition of what might constitute a sport
nutrition supplement is that the definition is not
exclusionary. In this context, everything from
aspirin to zinc could be considered a sport
nutrition supplement. In addition, one is left to
wrestle with ticklish questions such as whether
the effect of the ingested substance is nutritional,
physiological or pharmacological.
In the United States, the Dietary Supplement
Health Education Act of 1994 established a defi-
nition for dietary supplements that included the
following wording: ‘dietary supplement means a
product...intended to supplement the diet that
... contains one or more of the following dietary
ingredients: a vitamin; a mineral; an herb or
other botanical; an amino acid...a concentrate,
metabolite, constituent, extract’. In the 1994 Act,
it is estimated that 4000 such products are cur-
rently marketed in the US. Although this de-
scription includes many products positioned as
sports nutrition supplements, it excludes foods
and beverages formulated for use by physically
active people.
For the purpose of this chapter, it is necessary
to accept a broad definition, complete with its
attendant limitations, to allow for discussion of
the wide range of products that are marketed for
use by physically active people. A sport nutrition
product/supplement is any food, beverage, tablet, gel,
concentrate, powder, capsule, gelcap, geltab or liquid
droplet purported to affect body structure, function or
nutritional status in such a way as to be of value
to physically active people. To narrow the scope of
524 practical issues
discussion, it is necessary to exclude alcohol,
analgesics, caffeine, amphetamines, anabolic
steroids, hormones, b-blockers, diuretics and
otherpharmacologicalsubstances that may affect
structure and function but are not considered
nutrients.Objectives of nutritional
supplementation
Abiding by the definition above, an efficacious
sports nutrition product is one that provides a
structural, functional and/or nutritional benefit
that is documented by scientific research. For
example, an iron-deficient female runner who
supplements her diet with ferrous sulphate
tablets realizes a functional and nutritional
benefit that was not achieved by her usual diet. A
bodybuilder who is able to gain lean body mass
by ingesting a product that provides energy and
protein enjoys a structural benefit afforded by
that supplement. The cyclist who ingests a high-
carbohydrate beverage to help assure adequate
carbohydrate intake benefits from both struc-
tural (restoration of muscle and liver glycogen
stores) and functional (rapid recovery, increased
endurance) effects.
From a scientific standpoint, it is possible to
experimentally evaluate the ability of a product
to affect human structure or function. In fact, the
manufacturers of some sports nutrition products
require that rigorous scientific and legal stan-
dards be met before a product claim can be made.
Unfortunately, many manufacturers do not.Evaluating product claims
One only has to page through an issue of any
health- and fitness-related magazine to find
dozens of advertisements and articles on nutri-
tional supplements. For example, the March 1997
US edition of Muscle and Fitness(Weider Publica-
tions, Inc.), a popular health and fitness maga-
zine with international distribution, contains
nine separate articles and nearly 50 advertise-
ments on sports nutrition supplements. Product
claims are many and varied, including ‘helps