Nutritional Ergogenic Aids

Chapter 26
Nutritional Ergogenic Aids*
MELVIN H. WILLIAMS AND BRIAN C. LEUTHOLTZ
Introduction
The optimal production, control and efficiency of
human energy is the key composite determinant
of all muscular power for movement in sport. In
general, as noted in previous chapters, sport scientists recognize three major human muscle
energy systems important for the generation of
adenosine triphosphate (ATP) for muscle contraction and subsequent power production.
The ATP–phosphocreatine (ATP–PCr) energy
system, which uses adenosine triphosphate and
creatine phosphate as its fuel sources, generates
maximal anaerobic power for very short periods
of time, such as 10 s for a 100-m dash. The lactic
acid energy system, which utilizes carbohydrate
via anaerobic glycolysis, is capable of sustaining
high anaerobic power production, such as 45 s
for a 400-m run. The oxidative energy system,
which uses carbohydrates via aerobic glycolysis
and fats via b-oxidation, can sustain aerobic
power for prolonged endurance events, such as
130 min for a 42.2-km marathon.
The three human muscle energy systems
depend on various dietary nutrients for optimal
functioning. Dietary carbohydrates and fats, two
of the macronutrients, provide the main sources
of energy. Protein, another macronutrient, may
also serve as an energy source, but as the amino
* Small segments of this chapter have been extracted
from Melvin H. Williams, The Ergogenics Edge: Pushing
the Limits of Sports Performance, Human Kinetics Publishers, Champaign, IL, 1998.
356
acids released by protein degradation are either
reutilized or oxidized, the amount of protein oxidized per day must be replenished by dietary
intake. Protein is utilized primarily to synthesize
muscle tissue that serves as the structural
basis for energy production, and to synthesize
enzymes, hormones, and other physiological
substances that, along with vitamins and minerals (micronutrients), help regulate the myriad
of neural, hormonal and metabolic processes
involved in the release of energy from carbohydrates and fats for use during sport-related exercise tasks.
Most sport nutritionists recommend that athletes consume a balanced diet of macronutrients
and micronutrients to provide adequate energy,
regulate metabolic processes properly, and maintain an optimal body mass specific to their sport.
In general, dietary guidelines for healthy eating
developed for the average population are also
applicable to athletes. However, considerable
research effort has been expended to determine
whether or not dietary manipulation may be able
to enhance sport performance, and much of
this research has focused on the identification
and development of specific nutritional
ergogenic aids.
Nutritional ergogenic aids are purported to
enhance sport performance beyond that associated with the typical balanced diet. The major
categories targeted to physically active individuals include: megadoses of essential nutrients,
such as 1000 mg of vitamin C; engineered metabolic byproducts of essential nutrients, such as b-
nutritional ergogenic aids
hydroxy-b-methylbutyrate (HMB) from leucine;
nutraceuticals or phytochemicals, non-drug
substances found in plants that are purported to
affect metabolism, such as ginseng; non-essential
nutrients, such as creatine; and drug nutrients,
legal drugs found naturally in foods or beverages consumed by humans, such as alcohol and
caffeine. Examples of these nutritional ergogenic
aids can be categorized as follows.
1 Megadoses of essential nutrients:
(a) amino acids: arginine, ornithine, lysine and
tryptophan;
(b) vitamins: vitamin B12, vitamin C and
vitamin E;
(c) minerals: boron, chromium and
phosphates.
2 Engineered metabolic by-products of essential
nutrients:
(a) HMB (b-hydroxy-b-methylbutyrate);
(b) DHAP (dihydroxyacetone plus pyruvate);
(c) FDP (fructose diphosphate).
3 Non-essential nutrients:
(a) carnitine;
(b) choline;
(c) glycerol;
(d) inosine.
4 Plant extracts (phytochemicals):
(a) gamma oryzanol;
(b) ginseng;
(c) wheat germ oil;
(d) yohimbine.
5 Drug nutrients:
(a) alcohol;
(b) caffeine.
Nutritional ergogenic aids may be used in
attempts to increase sport performance in
various ways, such as: increased energy supply
in the muscle (e.g. creatine supplements);
increased energy-releasing metabolic processes
in the muscle (e.g. l-carnitine supplements);
enhanced oxygen delivery to the muscle (e.g.
iron supplements); increased oxygen utilization
in the muscle (e.g. coenzyme Q10 supplements);
decreased production or accumulation of
fatigue-causing metabolites in the muscle
(e.g. sodium bicarbonate supplements); and
improved neural control of muscle contraction
357
(e.g. choline supplements). Because all nutrients
may be involved in energy production or control
in one way or another, every nutrient may be
potentially ergogenic for specific sport tasks. The
potential capacity of many specific essential
and non-essential nutrients to enhance the three
human energy systems is detailed in other chapters of this volume, including the role of creatine
supplementation to enhance the ATP–PCr
energy system, the ingestion of sodium bicarbonate to improve performance in sport events associated with the lactic acid energy system, and
dietary carbohydrate regimens to increase
aerobic endurance capacity associated with the
oxygen energy system.
This brief review will focus on several nutritional ergogenics commonly marketed to athletes as dietary supplements with alleged
ergogenic properties to improve performance in
(i) strength/power sport tasks, and (ii) aerobic
endurance sport tasks.
Strength/power sport tasks
Arginine, ornithine and lysine
theory
Human growth hormone (hGH), a polypeptide,
is released from the pituitary gland into the
bloodstream and affects all body tissues. Supplementation with various amino acids, particularly
arginine, ornithine and lysine, has been used
in attempts to stimulate the release of hGH.
Increased serum levels of hGH in turn may
stimulate production and release of insulin-like
growth factor-1 that may lead to increases in
muscle mass and strength. Additionally, amino
acid supplementation is theorized to stimulate
the release of insulin, another anabolic hormone.
efficacy
In early research, Elam (1989) reported that in
conjunction with a weight-training programme,
supplementation with arginine (1 g · day–1) and
ornithine (1 g · day–1) reduced body fat, increased
358
nutrition and exercise
Fig. 26.1 Some athletes consume
nutritional ergogenic aids in
attempts to increase serum levels
of anabolic hormones, with
resultant expected benefits of
increased muscle mass, strength
and power. Photo © Allsport /
Botterill.
lean body mass, and increased strength over a
5-week period. However, this study has been
criticized on the grounds of poor experimental
design and statistical analysis. More recent
well-controlled studies (Fogelholm et al. 1993;
Lambert et al. 1993; Mitchell et al. 1993) with
experienced weightlifters or bodybuilders do not
support any ergogenic effect of various combinations of arginine, ornithine and lysine on hGH
secretion, increased muscle mass, strength or
power.
Moreover, two well-controlled studies
revealed that hGH supplementation itself did
not increase muscle protein synthesis, muscle
size or strength in untrained males undergoing
a 12-week resistance-training programme
(Yarasheski et al. 1992) or muscle protein synthesis or whole body protein breakdown in trained
weightlifters over a 2-week period (Yarasheski
et al. 1993).
engineered or produced by amino acid supplementation, are unknown (Bucci 1993).
safety
efficacy
Although moderate doses of amino acid supplements may be safe, larger doses, e.g. 170 mg
ornithine · kg–1 body weight, may lead to gastrointestinal distress (osmotic diarrhoea). Moreover, the potential adverse health effects of
hGH administration are substantial, and most
researchers caution that the long-term health
risks of hGH administration, either genetically
Animal studies involving poultry, cattle and pigs
have indicated that HMB supplementation may
increase lean muscle mass and decrease body fat.
(Nissen et al. 1994; Van Koevering et al. 1994).
However, HMB research with humans is very
limited and has emanated from a single laboratory. Collectively, three studies provide some
evidence supportive of an anabolic, or an anti-
b-Hydroxy-b-methylbutyrate
theory
b-Hydroxy-b-methylbutyrate is a metabolite
of the essential amino acid leucine, and is
currently being marketed as a dietary supplement, calcium-HMB-monohydrate. Although its
metabolic role in humans is uncertain, HMB supplementation is proposed to help exercisers maximize muscle gains during resistance training by
counteracting the catabolic effects of exerciseinduced stress on protein metabolism. Investigators hypothesize that HMB may be an essential
component of the cell membrane that is jeopardized during exercise stress or that it may regulate enzymes important to muscle growth.
nutritional ergogenic aids
catabolic, effect of HMB supplementation. In one
study, HMB supplementation (1.5 or 3.0 g ·
day–1), in a dose–response manner, induced significant improvements in lean body mass and
muscle strength in untrained men over a 3-week
period (Nissen et al. 1996b). In two other studies,
HMB supplementation (3 g · day–1) increased
strength in physically active males in the 1repetition maximal bench press (Nissen et al.
1996b) and decreased body fat and increased
lean body mass and bench press strength in both
trained and untrained subjects over a 4-week
period of resistance training (Nissen et al.
1996a).
Although these preliminary findings are
impressive, replication from other laboratories
is needed. Additionally, each study included
several threats to internal validity, including the
use of unorthodox measures of muscle strength
or absence of a true placebo, and in tests of multiple dependent variables, such as multiple measures of strength, HMB benefited performance in
some tests, but not all.
safety
Studies in humans at doses of 1.5–3.0 g · day–1 for
several weeks have reported no acute adverse
effects. Chronic supplementation has not evidenced adverse effects in animals, but no data
appear to be available for humans.
Herbal products
359
or stimulate its endogenous production, thus
inducing increases in muscle size and strength.
efficacy
A scientific literature review revealed no research
to validate the claims made by the manufacturers
that g-oryzanol, smilax or yohimbine either
raise serum testosterone levels or induce gains in
muscle size or strength, confirming the findings
of previous scientific reviews (Wheeler & Garleb
1991; Grunewald & Bailey 1993). Wheeler and
Garleb (1991) speculated that g-oryzanol might
actually decrease serum testosterone. Wellcontrolled research with these herbal products,
and other plant-derived purported ergogenics
such as dehydroepiandrosterone (DHEA), is
limited, but that which is available does not substantiate advertising claims. For example, Fry
and others (1997) recently reported that goryzanol supplementation (500 mg · day–1 for 9
weeks), in comparison to a placebo condition,
did not increase circulating concentrations of
testosterone or improve 1-repetition maximum
muscular strength in the bench press or squat
exercise.
safety
Although herbal dietary supplements may be
safe, most lack appropriate safety data. Some
preparations have been reported to cause
various health problems, including anaphylactic
reactions.
theory
Numerous herbal products have been marketed
as potential ergogenics for physically active individuals. Three such products have been marketed as bodybuilding supplements as a means
to enhance muscle size and strength: g-oryzanol,
a ferulic acid ester derived from rice bran
oil; yohimbine (yohimbe), a nitrogen-containing
alkaloid from the bark of the yohimbe tree; and
smilax, an extract of phytosterols from the dried
roots of Smilax officinalis or various forms of sarsaparilla. Advertisers theorize that these herbal
products contain the male hormone testosterone
Aerobic endurance sport tasks
Phosphorus (phosphates)
theory
Dietary phosphates, the source of the essential
nutrient phosphorus, are incorporated into
many compounds in the body that are involved
in energy metabolism, such as ATP as an energy
substrate, thiamin pyrophosphate as a vitamin
cofactor, sodium phosphate as a buffer, and 2,3diphosphoglycerate (2,3-DPG) for red blood cell
360
nutrition and exercise
function. All of these roles could provide
ergogenic potential, but the most researched
theory involves the effect of phosphate salt supplementation on 2,3-DPG levels. Increased levels
of 2,3-DPG could facilitate release of oxygen
from haemoglobin in the red blood cell and
possibly enhance aerobic endurance exercise
performance.
efficacy
Current research is equivocal as to whether or
not phosphate loading may improve physiological functions important to endurance performance. About a dozen studies have been
conducted. No study has reported decreases in
performance, and four well-controlled studies
(Cade et al. 1984; Kreider et al. 1990, 1992; Stewart
et al. 1990) have reported that phosphate supplementation may enhance exercise performance.
However, the underlying mechanism has not
been clarified. For example, 2,3-DPG did not
increase in all studies. Increased maximal oxygen uptake and improved performance on cycle
ergometer exercise tests are the most consistent
findings. Although these results are impressive, a
number of confounding variables in previous
research have been identified and more controlled research has been recommended
(Tremblay et al. 1994).
in animal foods but may also be synthesized in
the liver and kidney. l-Carnitine is the physiologically active form in the body and has been
the form most commonly used as a dietary
supplement.
l-Carnitine may affect various physiological
functions important to exercise; most of the
effects are ergogenic in nature but some may
possibly impair performance, i.e. be ergolytic
(Wagenmakers 1991; Williams 1995). A primary
function of l-carnitine is to facilitate transfer of
free fatty acids (FFA) into the mitochondria to
help promote oxidation of the FFA for energy.
Theoretically, l-carnitine supplementation could
enhance FFA oxidation and help to spare the use
of muscle glycogen, which might be theorized to
safety
Phosphate supplements may cause gastrointestinal distress unless consumed with ample fluids
or food. Chronic consumption, particularly with
limited calcium intake, can lead to a decreased
calcium to phosphate ratio, which may increase
parathyroid hormone secretion and impair
calcium balance.
L-Carnitine
theory
Carnitine, a non-essential short-chain carboxylic
acid, is a vitamin-like compound found naturally
Fig. 26.2 Theoretically, nutritional ergogenic aids may
enhance physiological or metabolic processes deemed
important for aerobic energy production. Photo ©
Allsport / Martin.
nutritional ergogenic aids
improve prolonged aerobic endurance capacity.
Additionally, by decreasing the ratio of acetylcoenzyme A (CoA) to CoA and hence stimulating
the activity of pyruvate dehydrogenase, lcarnitine supplementation may be theorized to
facilitate the oxidation of pyruvate. Such an
effect could reduce lactic acid accumulation and
improve anaerobic endurance exercise performance (Wagenmakers 1991). On the other hand,
the increased oxidation of glucose could lead to
an earlier depletion of muscle glycogen and
impair performance, an ergolytic effect
(Wagenmakers 1991).
361
performance in either a marathon or a 20-km run,
but this dose may have been insufficient compared to chronic supplementation protocols.
safety
l-Carnitine appears to be safe in dosages utilized
in these studies, although large doses may cause
diarrhoea. Individuals should not use supplements containing d-carnitine. The d-carnitine
isomer may impair the synthesis of l-carnitine
in the body leading to symptoms of l-carnitine
deficiency, including myopathy and muscular
weakness.
efficacy
Although l-carnitine supplementation will
increase plasma levels of carnitine, it has not
been shown to consistently increase muscle carnitine levels, the site of its action relative to the
use of FFA for energy production during exercise
(Wagenmakers 1991; Williams 1995). The data
are equivocal relative to the effects of l-carnitine
supplementation on the use of FFA during exer.
cise and Vo2max., with some studies providing
evidence of enhanced FFA utilization and
.
increased Vo2max. and other studies showing no
effect on energy metabolism (Kanter & Williams
1995; Williams 1995; Heinonen 1996). On the
other hand, research data clearly indicate that lcarnitine supplementation does not affect lactic
acid accumulation in a fashion that may be considered to be ergogenic (Kanter & Williams 1995;
Williams 1995). Also, in general, in those studies
that included physical performance measures, lcarnitine supplementation has not been shown
to enhance either aerobic or anaerobic exercise
performance (Kanter & Williams 1995; Williams
1995). However, research is needed to investigate
the potential ergogenic effects of chronic lcarnitine supplementation on prolonged aerobic
endurance exercise tasks, such as marathon
running, to test the possibility of muscle glycogen sparing and subsequent improved performance. Colambani and others (1996) found that
acute supplementation of l-carnitine (2 g · 2 h–1
before the events) had no significant effect on
Coenzyme Q10
theory
Coenzyme Q10 (CoQ10), a non-essential nutrient,
is a lipid with characteristics common to vitamins. It is located primarily in the mitochondria
of the cells, such as heart and muscle cells, and is
involved in the processing of oxygen for the production of cellular energy. Increased processing
of oxygen could increase sport performance
in aerobic endurance events. CoQ10 is also
an antioxidant. CoQ10 is also referred to as
ubiquinone, or ubiquinone-10.
efficacy
Bucci (1993) cites six studies showing beneficial
effects of CoQ10 supplementation to various
subject populations, but these studies appeared
in the proceedings of a conference and do not
appear to have been published in peer-reviewed
journals. Moreover, each study suffered one or
more experimental design flaws, e.g. no control
group (Williams 1999).
A recent review of six well-controlled scientific
studies involving CoQ10 supplementation (ª
70–150 mg · day–1 for 4–8 weeks) either administered separately or in combination with other
putative ergogenic nutrients, indicated that
although blood levels of CoQ10 may be increased,
there was no effect on lipid peroxidation, sub-
362
nutrition and exercise
strate utilization, serum lactate levels, oxygen
uptake, cardiac function or anaerobic threshold
during submaximal exercise or serum lactate
levels and oxygen uptake during maximal exercise. Additionally, there was no effect on time to
exhaustion on a cycle ergometer in two studies
(Williams 1999).
Bucci (1993) indicates that the long-term safety
of CoQ10 has been thoroughly documented,
although others indicate that it may actually
serve as a pro-oxidant and generate free radicals
(Demopoulous et al. 1986). In a recent study,
Malm and others (1996) reported evidence of
muscle tissue damage in exercising subjects who
were supplemented with 120 mg CoQ10 · day–1
for 20 days.
supplementation helped prevent a decrease
in serum choline in triathletes and adolescent
runners following long-term hard physical
stress, but they did not evaluate the effects on
performance. No studies of choline supplementation and physical performance were presented
in a recent review (Kanter & Williams 1995). Subsequent to this review, a double-blind, placebocontrolled, crossover study with trained male
cyclists, using a single dosage of 2.43 g choline
bitartrate, reported that although there was a significant increase in serum choline, compared
with the placebo there were no significant effects
on time to exhaustion in either a high intensity
.
.
(150% Vo2max.) or a prolonged (70% Vo2max.) cycle
exercise test (Spector et al. 1995). At the present
time, there are no data to support choline supplementation as an effective ergogenic, but confirming research is desirable.
Choline
safety
safety
theory
Choline, a non-essential nutrient, is an amine
widely distributed in foods and may also be synthesized in the body. Its primary metabolic role
in humans is to serve as a precursor for the
formation of phosphatidylcholine (lecithin) and
other essential components of cell membranes
and for the formation of acetylcholine, the neurotransmitter at the myoneural junction that
initiates electrical events in muscle contraction.
Conlay et al. (1992) reported significantly
lower plasma choline levels following a 42.2-km
marathon, suggestive as an aetiologic factor in
the development of fatigue because of the possibility of decreased acetylcholine production
and resultant impaired muscular contractility.
Theoretically, choline supplementation will
enhance acetylcholine synthesis and prevent
acetylcholine depletion and subsequent fatigue
in endurance events.
efficacy
Von Allwörden et al. (1993) noted that lecithin
Choline is a natural dietary component and
small supplemental doses are not considered
unsafe.
Inosine
theory
Inosine, a non-essential nutrient, is a nucleoside.
Some in vitro research has led to the theory that
inosine supplementation increases the amount
of 2,3-DPG in the red blood cell. Theoretically,
increased levels of 2,3-DPG may facilitate the
release of oxygen from the red blood cells to the
muscle and enhance aerobic endurance exercise.
efficacy
Only two well-controlled studies have evaluated
the purported ergogenic effect of inosine supplementation. Two days of inosine supplementation
(6000 mg · day–1) exerted no significant effect on
heart rate, ventilation, oxygen consumption, or
lactic acid production in highly trained runners
during both submaximal and maximal exercise,
nutritional ergogenic aids
nor was there any effect on performance in a 4.8km treadmill run for time (Williams et al. 1990).
Five days of inosine supplementation (5000 mg ·
day–1) did not influence peak power, end power,
a fatigue index, total work, or post-test lactate in
competitive male cyclists undertaking several
cycle ergometer exercise tasks (Starling et al.
1996). In both studies, inosine supplementation
actually impaired performance in some of the
tests, including run time to exhaustion in a peak
oxygen uptake test (Williams et al. 1990) and
time to fatigue in a supramaximal cycling sprint
(Starling et al. 1996).
363
tion, and cycling exercise performance under
warm/hot environmental conditions (Lyons
et al. 1990; Montner et al. 1992). However, Lamb
and others (1997) reported that glycerol-induced
hyperhydration exerted no significant effect on
temperature regulation, physiological or metabolic responses to exercise, or prolonged cycling
performance. Additional research is needed to
help resolve these contradictory findings,
particularly so in sports in which the extra body
mass needs to be moved, such as distance
running.
safety
safety
Inosine supplementation appears to be relatively
safe, but may increase production of uric acid
which could lead to complications in those
afflicted with gout.
Glycerol
theory
Glycerol is an alcohol derived from triglycerides.
Investigators theorize that a combination of
glycerol–water supplementation may be a more
effective hyperhydration technique than water
hyperhydration alone. Increasing body water
stores may be theorized to enhance aerobic
endurance performance, either by increasing
blood volume or by increasing resistance to
dehydration while exercising under heat-stress
environmental conditions.
efficacy
Glycerol-induced hyperhydration (ª 1 g glycerol ·
kg–1 body weight with 20–25 ml water · g–1 glycerol), when compared with water hyperhydration alone, has been shown to increase total
body water, including blood volume, to a greater
extent (DeLuca et al. 1993; Freund et al. 1993;
Sawka et al. 1993). Several studies have shown
that glycerol-induced hyperhydration improves
cardiovascular responses, temperature regula-
Although the dosages used in these studies
appear to be safe, larger doses may lead to abnormal pressures in tissue spaces.
Ginseng
theory
Ginseng, a plant extract, is a generic term encompassing a wide variety of compounds derived
from the family Araliaceae. The ergogenic effect
of ginseng is attributed to specific glycosides,
also referred to as ginseng saponins or ginsenosides. The specific physiological effects of
ginseng extracts depend on the plant species, the
various forms including Chinese or Korean
ginseng (Panax ginseng), American ginseng (P.
quinquefolium), Japanese ginseng (P. japonicum)
and Russian/Siberian ginseng (Eleutherococcus
senticosus). Although the mechanism underlying
the alleged ergogenicity of ginseng on physical
performance has not been defined, theories
include stimulation of the hypothalamic–
pituitary–adrenal cortex axis and increased
resistance to the stress of exercise, enhanced
myocardial metabolism, increased haemoglobin
levels, vasodilation, increased oxygen extraction
by muscles, and improved mitochondrial metabolism in the muscle, all of which theoretically
could enhance aerobic exercise performance
(Dowling et al. 1996).
364
nutrition and exercise
efficacy
There are very few well-controlled studies supporting an ergogenic effect of ginseng supplementation. In their major recent review of
the ergogenic properties of ginseng, Bahrke and
Morgan (1994) indicated that because of methodological and statistical shortcomings, there is no
compelling evidence to indicate ginseng supplementation consistently enhances human physical performance and there remains a need for
well-designed research to address this issue. One
recent well-designed study (Pieralisi et al. 1991)
did find an ergogenic effect of Geriatric Pharmaton (a preparation including ginseng G115
and other elements, including dimethylaminoethanol) on various physiologic variables,
.
including Vo2max., and performance during the
Bruce treadmill protocol. However, the investigators noted that the ergogenic effect is attributed to the total preparation used, i.e. Geriatric
Pharmaton, and not to the standardized ginseng
G115, because some research has supported
a beneficial effect of dimethylaminoethanol
bitartrate, possibly by affecting favourably
the choline–acetylcholine complex. However,
several recent studies with appropriate designs
have not reported any benefits to endurance performance. For example, no significant ergogenic
effects were associated with 6 weeks of Eleutherococcus senticosus Maxim L (ESML) supplementation in highly trained runners on any
metabolic, psychological or performance parameters measured in both a submaximal and
maximal aerobic exercise task, including heart
.
. . .
rate, Vo2, VE, VE/Vo2, and respiratory exchange
ratio during both exercise and recovery, ratings
of perceived exertion during exercise, serum
(lactate) following exercise, and run time to
exhaustion in a maximal test (Dowling et al.
1996). Additionally, Morris and others (1996), in a
double-blind, placebo-controlled study, reported
no effect of a standardized ginseng extract (8 or
16 mg · kg–1 body mass for 7 days) on ratings of
perceived exertion or time to exhaustion on a
cycle ergometer test.
Nevertheless, quality research evidence
regarding the effect of ginseng supplementation
on exercise performance is limited and more controlled research is needed with varying types,
dosages, and physical performance parameters.
safety
Animal studies indicate that extracts of ginseng
have a low acute or chronic toxicity and the doses
normally used with humans are regarded as
safe. However, Beltz and Doring (1993) noted a
ginseng-abuse syndrome has been reported,
with such symptoms as hypertension, nervousness, sleeplessness and oedema.
Conclusion
Nutritional ergogenics have been used since time
immemorial, and will continue to be used as long
as athletes believe they may gain a competitive
advantage. However, before using such supplements for their purported ergogenic effects, one
should address the following questions.
Is it effective? If the supplement has not been
shown to be effective, either by appropriately
designed research or repeated personal experiences, there is no reason to buy it.
Is it safe? Most nutrient and dietary supplements are presumed to be safe if consumed in
recommended dosages. However, athletes often
believe that if one is good, 10 is better, and may
take amounts in excess of normal needs (Burke &
Read 1993). Excess amounts of various nutrients
and dietary supplements may pose health risks
to some individuals.
Is it legal? Most nutritional ergogenics are considered legal because they are regulated as food
or dietary supplements, not drugs. However, the
same dietary supplements may contain drugs,
such as caffeine and ephedrine, which may lead
to a positive doping test.
Athletes should be allowed to utilize any effective, safe and legal nutritional supplement in
attempts to enhance sport performance, just as
they should be able to use the most effective and
legal equipment specific to their sport which
may provide a mechanical edge.
nutritional ergogenic aids
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