Herbal Diuretics. This is a new type of
supplement recently marketed as a natural
way to promote weight loss. There is limited
evidence that taraxacum officinale, verbena
officinalis, lithospermum officinale,
equisetum arvense, arctostaphylos uva-ursi,
arctium lappa and silene saxifraga infusion
may affect diuresis in animals 282, 283. Two
studies presented at the 2001 American
College of Sports Medicine meeting 284, 285
indicated that although herbal diuretics
promoted a small amount of dehydration
(about 0.3% in one day), they were not nearly
as effective as a common diuretic drug (about
3.1% dehydration in one day). Consequently,
although more research is needed, the
potential value of herbal diuretics as a weight
loss supplement appears limited.
Performance Enhancement Supplements
A number of nutritional supplements have
been proposed to enhance exercise
performance. Some of these nutrients have
been described above. Table 3 categorizes
the proposed ergogenic nutrients into
apparently safe and effective, possibly
effective, too early to tell, and apparently
ineffective. Weight gain supplements
purported to increase muscle mass may also
have ergogenic properties if they also
promote increases in strength. Similarly,
some sports may benefit from reductions in
fat mass. Therefore, weight loss supplements
that help athletes manage body weight and/or
fat mass may also posses some ergogenic
benefit. The following describes which
supplements may or may not affect
performance that were not previously
described. Based on this analysis, Table 4
summarizes the general nutritional
recommendations for athletes and which
dietary supplements may help power and
endurance athletes.

Apparently Effective
Water and Sports Drinks. Preventing
dehydration during exercise is one of the keys
of maintaining exercise performance
(particularly in hot/humid environments).
People engaged in intense exercise or work in
the heat need to frequently ingest water or
sports drinks (e.g., 1-2 cups every 10 – 15
minutes). The goal should be not to lose
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26
more than 2% of body weight during exercise
(e.g., 180 lbs x 0.02 = 3.6 lbs). Sports drinks
contain salt and carbohydrate. Studies show
that ingestion of sports drinks during exercise
in hot/humid environments can help prevent
dehydration and improve endurance exercise
capacity 43. Consequently, frequent ingestion
of water and/or sports drinks during exercise
is one of the easiest and most effective
ergogenic aids.
Carbohydrate. General nutritional needs
were discussed earlier. However, one of the
best ergogenic aids available for active people
is carbohydrate. Athletes and active
individuals should consume a diet high in
carbohydrate (e.g., 55 – 65% of calories or 5-
8 grams/kg/day) in order to maintain muscle
and liver carbohydrate stores 1. Additionally,
ingesting a small amount of carbohydrate and
protein 30-60 minutes prior to exercise and
use of sports drinks during exercise can
increase carbohydrate availability and
improve exercise performance. Finally,
ingesting carbohydrate and protein
immediately following exercise can enhance
carbohydrate storage and protein synthesis 1.
Creatine. Earlier we indicated that creatine
supplementation is one of the best
supplements available to increase muscle
mass and strength during training. However,
creatine has also been reported to improve
exercise capacity in a variety of events 54.
This is particularly true when performing high
intensity, intermittent exercise such as
multiple sets of weight lifting, repeated
sprints, and/or exercise involving sprinting
and jogging (e.g., soccer) 54. Although
studies evaluating the ergogenic value of
creatine on endurance exercise performance
are mixed, endurance athletes may also
theoretically benefit in several ways. For
example, increasing creatine stores prior to
carbohydrate loading (i.e., increasing dietary
carbohydrate intake before competition in an
attempt to maximize carbohydrate stores) has
been shown to improve the ability to store
carbohydrate 286-288. Further, coingesting
creatine with carbohydrate has been shown to
optimize creatine and carbohydrate loading
289. Most endurance athletes also perform
interval training (sprint or speed work) in an
attempt to improve anaerobic threshold.
Since creatine has been reported to enhance
interval sprint performance, creatine
supplementation during training may improve
training adaptations in endurance athletes 290,
291. Finally, many endurance athletes lose
weight during their competitive season.
Creatine supplementation during training may
help people maintain weight.
Sodium Phosphate. We previously
mentioned that sodium phosphate
supplementation may increase resting energy
expenditure and therefore could serve as a
potential weight loss nutrient. However, most
research on sodium phosphate has actually
evaluated the potential ergogenic value. A
number of studies indicated that sodium
phosphate supplementation (e.g., 1 gram
taken 4 times daily for 3-6 days) can increase
maximal oxygen uptake (i.e., maximal
aerobic capacity) and anaerobic threshold by
5-10% 219, 220, 292, 293. These finding suggest
that sodium phosphate may be highly
effective in improving endurance exercise
capacity. Other forms of phosphate (i.e.,
calcium phosphate, potassium phosphate) do
not appear to possess ergogenic value.
Sodium Bicarbonate (Baking Soda). During
high intensity exercise, acid (H+) and carbon
dioxide (CO2) accumulate in the muscle and
blood. One of the ways you get rid of the
acidity and CO2 is to buffer the acid and CO2
with bicarbonate ions. The acid and CO2 are
then removed in the lungs. Bicarbonate
loading (e.g., 0.3 grams per kg taken 60-90
minutes prior to exercise or 5 grams taken 2
times per day for 5-days) has been shown to
be an effective way to buffer acidity during
high intensity exercise lasting 1-3 minutes in
duration 294-297. This can improve exercise
capacity in events like the 400 - 800 m run or
100 – 200 m swim 298. Although bicarbonate
loading can improve exercise, some people
have difficulty with their stomach tolerating
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27
bicarbonate as it may cause gastrointestinal
distress.
Caffeine. Caffeine is a naturally derived
stimulant found in many nutritional
supplements typically as Gaurana, Bissey
Nut, or Kola. Caffeine can also be found in
coffee, tea, soft drinks, energy drinks, and
chocolate. Studies indicate that ingestion of
caffeine (e.g., 3-9 mg/kg taken 30 – 90
minutes before exercise) can spare
carbohydrate use during exercise and thereby
improve endurance exercise capacity 295, 299.
People who drink caffeinated drinks
regularly, however, appear to experience less
ergogenic benefits from caffeine 300.
Additionally, some concern has been
expressed that ingestion of caffeine prior to
exercise may contribute to dehydration
although recent studies have not supported
this concern 301-303. Caffeine doses above 9
mg/kg can result in urinary caffeine levels
that surpass the doping threshold for many
sport organizations. Suggestions that there is
no ergogenic value to caffeine
supplementation is not supported by the
preponderance of available scientific studies.

Possibly Effective
Post-Exercise Carbohydrate and Protein.
Ingesting carbohydrate and protein following
exercise enhances carbohydrate storage and
protein synthesis. Theoretically, ingesting
carbohydrate and protein following exercise
may lead to greater training adaptations. In
support of this theory, Esmarck and
coworkers 93 found that ingesting
carbohydrate and protein immediately
following exercise doubled training
adaptations in comparison to waiting until 2-
hours to ingest carbohydrate and protein.
Additionally, Tarnopolsky and associates 304
reported that post-exercise ingestion of
carbohydrate with protein promoted as much
strength gains as ingesting creatine with
carbohydrate during training. These findings
underscore the importance of post-exercise
carbohydrate and protein ingestion.
Glutamine. As described above, glutamine
has been shown to influence protein synthesis
and help maintain the immune system.
Theoretically, glutamine supplementation
during training should enhance gains in
strength and muscle mass as well as help
athletes tolerate training to a better degree.
Although there is some evidence that
glutamine supplementation with protein can
improve training adaptations, more research is
needed to determine the ergogenic value in
athletes.
Essential Amino Acids (EAA). Ingestion of
3-6 grams of EAA following resistance
exercise has been shown to increase protein
synthesis 84-92. Theoretically, ingestion of
EAA after exercise should enhance gains in
strength and muscle mass during training.
While there is sound theoretical rationale, it is
currently unclear whether following this
strategy would lead to greater training
adaptations and/or whether EAA
supplementation would be better than simply
ingesting carbohydrate and a quality protein
following exercise.
Branched Chain Amino Acids (BCAA).
Ingestion of BCAA (e.g., 6-10 grams per
hour) with sports drinks during prolonged
exercise would theoretically improve
psychological perception of fatigue (i.e.,
central fatigue). Although there is strong
rationale, the effects of BCAA
supplementation on exercise performance is
mixed with some studies suggesting an
improvement and others showing no effect 36.
More research is needed before conclusions
can be drawn.
Calcium β-HMB. HMB supplementation has
been reported to improve training adaptations
in untrained individuals initiating training as
well as help reduce muscle breakdown in
runners. Theoretically, this should enhance
training adaptations in athletes. However,
most studies show little benefit of HMB
supplementation in athletes.
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Glycerol. Ingesting glycerol with water has
been reported to increase fluid retention 305.
Theoretically, this should help athletes
prevent dehydration during prolonged
exercise and improve performance
particularly if they are susceptible to
dehydration. Although studies indicate that
glycerol can significantly enhance body fluid,
studies are mixed on whether it can improve
exercise capacity 52, 306-311.
Ephedrine/Caffeine. Most research has
evaluated the effects of ingesting ephedrine
and caffeine (EC) supplements on weight
loss. However, since ephedra and caffeine are
stimulants and caffeine has been shown to
have ergogenic properties, there has also been
interest in the potential ergogenic value of
EC. Recent research has shown that ingestion
of low to moderate amounts of synthetic EC
supplements generally improves endurance
and high intensity exercise performance with
no apparent adverse effects 312-316. However,
it is unclear whether dietary supplements
containing botanical ephedrine (i.e., ephedra)
and caffeine (e.g., kola nut) have similar
effects on performance. Further, since most
sport organizations ban use of ephedrine the
potential use in athletes appears limited.

Too Early to Tell
A number of supplements purported to
enhance performance and/or training
adaptation fall under this category. This
includes the weight gain and weight loss
supplements listed in Table 3 as well as the
following supplements not previously
described in this category.
Medium Chain Triglycerides (MCT).
MCT’s are shorter chain fatty acids that can
easily enter the mitochondria of the cell and
be converted to energy through fat
metabolism 317. Studies are mixed as to
whether MCT’s can serve as an effective
source of fat during exercise metabolism
and/or improve exercise performance 318-322.
Ribose. Ribose is a 3-carbon carbohydrate
that is involved in the synthesis of adenosine
triphosphate (ATP) in the muscle (the useable
form of energy). Clinical studies have shown
that ribose supplementation can increase
exercise capacity in heart patients 323-327. For
this reason, ribose has been suggested to be an
ergogenic aid for athletes. Although more
research is needed, most studies show no
ergogenic value of ribose supplementation on
exercise capacity in health untrained or
trained populations 328-330.

Apparently Ineffective
Inosine. Inosine is a building block for DNA
and RNA that is found in muscle. Inosine has
a number of potentially important roles that
may enhance training and/or exercise
performance 331. Although there is some
theoretical rationale, available studies indicate
that inosine supplementation has no apparent
affect on exercise performance capacity 332-
334.
Supplements to Promote General Health
In addition to the supplements previously
described, several nutrients have been
suggested to help athletes stay healthy during
intense training. For example, the American
Medical Association recently recommended
that all Americans ingest a daily low-dose
multivitamin in order to ensure that people get
a sufficient amount of vitamins and minerals
in their diet. Although one-a-day vitamin
supplementation has not been found to
improve exercise capacity in athletes, it may
make sense to take a daily vitamin
supplement for health reasons. Glucosomine
and chondroitin have been reported to slow
cartilage degeneration and reduce the degree
of joint pain in active individuals which may
help athletes postpone and/or prevent joint
problems 335, 336. Vitamin C, glutamine,
Echinacea, and zinc have been reported to
enhance immune function 42, 337-339.
Consequently, some sport nutritionists
recommend that athletes who feel a cold
coming on take these nutrients in order to
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enhance immune function 42, 337-339.
Similarly, nutrients such as vitamins E and C
may help restore overwhelmed anti-oxidant
defenses exhibited by athletes and reduce the
risk of numerous chronic diseases 340.
Creatine, calcium ß-HMB, BCAA, and Lcarnitine
have been shown to help athletes
tolerate heavy training periods 36, 74, 80, 81, 83,
341-344. Finally, omega-3 fatty acids, in
supplemental form, are now endorsed by the
American Heart Association for heart health
in certain individuals 345. This supportive
supplement position stems from: 1.) an
inability to consume cardio-protective
amounts by diet alone; and, 2.) the mercury
contamination sometimes present in wholefood
sources of DHA (docosahexaenoic acid)
and EPA (eicosapentaenoic acid) found in
fatty fish. Consequently, prudent use of
these types of nutrients at various times
during training may help athletes stay healthy
and/or tolerate training to a greater degree 37.

SUMMARY
Numerous nutritional and herbal products are
marketed to promote weight gain, weight loss,
and/or improve performance. Most have a
theoretical basis for use but little data
supporting safety and efficacy in athletes. A
number are heavily marketed despite data
indicating that they do not affect body
composition, performance, and/or training
adaptations at the dosages recommended. It
is in these particular situations that
unsupported claims explicitly or implicitly
endorsed by sport nutrition specialists
constitute fraud and/ or “quackery”. Prudent
training, maintaining an energy balance and
nutrient dense diet, proper timing of nutrient
intake, and obtaining adequate rest are the
cornerstones to enhancing performance and/or
training adaptations. Use of a limited number
of nutritional supplements that research has
supported can help improve energy
availability (e.g., sports drinks, carbohydrate,
creatine, caffeine, etc) and/or promote
recovery (carbohydrate, protein, essential
amino acids, etc) can provide additional
benefit in certain instances. The sport
nutrition specialist should stay up to date
regarding the role of nutrition on exercise so
they can provide honest and accurate
information to their students, clients, and/or
athletes about the role of nutrition and dietary
supplements on performance and training.
Furthermore, the sport nutrition specialist
should actively participate in exercise
nutrition research; write unbiased scholarly
reviews for journals and lay publications; help
disseminate the latest research findings to the
public so they can make informed decisions
about appropriate methods of exercise,
dieting, and/or whether various nutritional
supplements can affect health, performance,
and/or training; and, disclose any commercial
or financial conflicts of interest during such
promulgations to the public. Finally, sport
nutrition specialists can challenge companies
who sell exercise equipment and/or nutritional
supplements to develop scientifically based
products, conduct research on their products,
and honestly market the results of studies so
consumers can make informed decisions.