What is a dietary
supplement? The
Dietary Supplement Health and Education Act, defines
dietary supplements as a product (other than tobacco) intended
to supplement the diet that bears or contains one or more
of the following dietary ingredients: a vitamin, mineral,
amino acid, herb or other botanical dietary substance for
use to supplement the diet by increasing the total dietary
intake; a concentrate, metabolite, constituent, extract,
or combination of any ingredient described above and intended
for ingestion in the form of a capsule, powder, soft gel,
or gelcap, and not represented as a conventional food or
as a sole item of a meal or the diet (NIH,
Office of Dietary Supplements).
A dietary supplement is also defined as a
product which has the following properties (Burke and Read,
1993): Contains nutrients in amounts similar to the level
specified by the recommended dietary allowances to intakes
(RDA/RDIs) and similar to amounts found in food. Provides
a convenient or practical means of ingesting nutrients especially
in a sports setting. Allows or aids in achievement of known
physiologic or nutritional requirements of an athlete. Contains
nutrients in large amounts for use in reversing a known
nutritional deficiency. The efficacy of using the supplements
correctly has been acknowledged by exercise physiologists
and sports nutrition experts.
What
are ergogenic aids?
The word "ergogenic" is derived from the Greek
word (ergon) which means to increase work or potential for
work. Compounds such as bee pollen, caffeine, glycine, carnitine,
lecithin, brewer's yeast, and gelatin are claimed through
anecdotal evidence to improve strength or endurance. Although
ergogenic agents have been popular among athletes, scientific
research has failed to substantiate the claims of these
products; however, in some cases, such as caffeine, the
research results are equivocal (American Dietetic Association;
Slavin and Joensen, 1985).
What is the history of
dietary supplement use?
Throughout history people have been looking for foods and
substances to improve their physical strength. A belief
was held by medieval doctors that warriors should eat human
hearts to increase bravery, brains to increase intelligence,
and pituitary extracts to enhance muscle strength. Greek
Olympians from 300 BC used mushrooms to enhance performance.
Dutch swimmers in 1865 used caffeine as an ergogen. Late
1800 Belgian athletes dipped sugar cubes in ether. Ultra
endurance marathon runners used a cactus based stimulant
to enhance performance (Wadler and Hainline, 1989; Ridgway,
Thompson, Dangelmaier, 1995). Athletes are still searching
for supplements that will give them an extra edge in their
competitions.
Dietary supplements are widely available through
many commercial sources including health food stores, grocery
stores, pharmacies, and by mail. A review of literature
on the use of vitamins and minerals among athletes showed
that athletes in general use supplements more often than
35-40% of the general population who use supplements and
the 20-25% of the adolescents who use supplements (Sobal
and Marquart, 1994). Elite athletes had a mean supplement
use of 59% and college athletes had a mean supplement use
of 43%. Multivitamins were the most frequent type of nutritional
supplements. The second most frequent was vitamin C, followed
by iron, B-complex vitamins, vitamin E, calcium, and vitamin
A. Iron supplements were used more frequently by women athletes
and often in very high amounts (Sobal and Marquart, 1994).
According to another study more than 50% of elite women
distance runners, non-elite women marathon runners and Ironman
tri-athletes of both sexes used vitamin and mineral supplements
(Haymes, 1991). Supplement use is most prevalent in sports
emphasizing muscle size such as weight lifting or body building
(Burke, Gollan, Read, 1991).
Why do athletes use dietary
supplements?
Athletes have used supplements for many reasons. Sobal and
Marquart (1994) have suggested that athletes have used supplements
to improve performance through increased endurance, muscular
strength/power, recovery from heavy workouts, and to prevent
illness when the severe exertions related to sport may increase
the chances of illness.
What are the possible
hazards of using unregulated supplements?
Some athletes may be misled by strong, false claims of some
products currently on the market. To deter false claims
the FDA has mandated
that all the nutrients in dietary supplements be listed
on the labels (since July 1995). Some herbal products and
nutritional supplements may contain banned substances such
as ephedrine or androstendione. In 1989 there were 32 deaths
from using L-Tryptophan amino acid. Some athletes may believe
that certain foods and supplements enhance performance.
These products may provide certain psychological effects
because of the placebo effect rather than the physiological
effects. When the use of these substances replaces a balanced
nutritional program it can cause serious health consequences
(Source: ADA).
Many popular fad diets supply large amounts of saturated
fat and cholesterol which are associated with cardiovascular
disease. Some diets that are low in carbohydrates are not
appropriate for athletes because of problems with secondary
dehydration. Almost all the popular fad diets are nutritionally
inadequate. Low calorie diets can not meet the training
needs of athletes and promote loss of lean body mass and
depletion of carbohydrate stores (Berning and Steen, 1991).
Many substances are banned by the NCAA and student athletes
who use them may lose their eligibility to compete!
How
can I decide if a nutritional supplement is acceptable to
take?
Student athletes should take every precaution to ensure
that they are not taking any substance that will prevent
them from participation, or that may result in a positive
drug test. The American Dietetic Association (ADA)
offers the following:
Beware of claims that the products being advertised
will produce rapid results.
Beware of claims for products that seem unreasonably
distorted e.g "25 lbs of muscle in one month."
Be cautious about oversimplified conclusions that
come from a complex scientifically designed study.
Be aware of recommendations that have been taken from
one study that supports the sale of the product.
Remember that dramatic statements do not usually come
from well-designed accurately reported research findings.
Be alert to lists that divide food into "good"
and "bad" substances.
Be cautious about recommendations that focus only
on selling the product.
Be aware of recommendations that are taken from studies
that have been published without peer review.
Be aware of studies that present recommendations from
studies that have not compared different reactions among
individuals or groups
Student athletes should always check with
their team athletic trainer or team physician, and check
the NCAA banned drug list before using any substance.
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