your body use oxygen more efficiently’, ‘help
sculpt a leaner, firmer body’, ‘contains powerful
cell volumizing and recovery nutrients’, ‘the
most effective antioxidant nutrients’, ‘increases
muscle protein synthesis while increasing cell
hydration’, ‘promotes protein synthesis and
glycogen storage, supports immune function
and cell volumizing, and limits catabolism by
cortisol for optimal workout recovery’, ‘increase
levels of adenosine triphosphate’, ‘more lean-
gained mass in less time’, ‘prevents muscle loss
during training and dieting’, ‘improve strength
and stamina during workouts’, ‘increases lean
muscle mass and promotes fat loss’, and
‘increase peak power output, mean body mass,
and muscular performance’. Each of these
product claims involves a structural or func-
tional benefit that is directly testable through sci-
entific experimentation. Although a few of these
advertising claims were accompanied by a scien-
tific reference, the vast majority were not. This
observation is similar to that of Grunewald and
Bailey (1993), who evaluated the advertising
claims for 624 products targeted at bodybuilders.
The products were associated with over 800
performance-related claims, the vast majority of
which were unsubstantiated by scientific
research.
If the stated objective of a sports nutrition sup-
plement is to provide a structural or functional
benefit, validation of the claim can be accom-
plished in two ways. The highest level of scien-
tific validation for the efficacy of a nutrition
supplement is generated by research published
in peer-reviewed scientific journals. In this
context, the strongest such support is developed
when numerous laboratories report similar find-
ings of product effectiveness. A case in point is
the scientific consensus that has been developed
for carbohydrate–electrolyte beverages on the
basis of more than 100 scientific studies pub-
lished in peer-reviewed journals. The other
acceptable example of scientific credibility is
when the efficacy of a nutrition supplement can
be established by face validity—that is, when the
claims made for the product are widely recog-
nized as being both truthful and scientifically
valid. For example, if a product containing large
amounts of carbohydrate per serving is claimed
to provide a supplemental source of dietary
carbohydrate that helps in glycogen restoration,
the product’s efficacy in that regard enjoys the
benefit of face validity. The product claim is
accepted as true on its face.
Butterfield (1996) and other authors (Burke
1992; Rangachari & Mierson 1995; Sherman &
Lamb 1995; Coleman & Nelson Steen 1996) have
suggested guidelines for evaluating research
results and product claims. Sherman and Lamb
(1995) identified 10 essential characteristics that
should be present in an acceptable experimental
design. These include:
1 use of an appropriate subject population;
2 adequate control of diet and exercise;
3 use of a double-blind design with placebo;
4 random assignment of subjects to treatment
groups;
5 repeated measures or cross-over designs to
reduce the impact of individual differences;
6 inclusion of appropriate familiarization
trials;
7 adequate control of possible mitigating
factors such as environmental conditions and
hydration status;
8 measurement of variables related to the
potential mechanism of effect;
9 an acceptable number of subjects to assure
ample statistical power; and
10 proper statistical analyses.
A critical evaluation of research data requires
a trained and experienced eye. Even the most
sceptical layperson is unprepared to undertake a
thorough review of product claims and related
literature. As a result, it is the responsibility of the
trained sports health professional to be proactive
in providing the public with clear and accurate
guidance regarding the efficacy of products that
claim to provide structural or functional benefits.
The advertisements for some sports nutrition
products rely solely upon claims of nutrient
content rather than structural or functional
claims. The product’s label and advertising
merely make a statement regarding the product’s
nutritional content. Examples of such claims