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Competitive
cyclists who have achieved maximal results from their training
programs often turn to extrinsic aids (termed ergogenic aids)
to enhance their performance.
These include mechanical aids (equipment), psychological
aids (hypnosis, psychotherapy), pharmacological aids (erythropoietin)
and nutritional aids (creatine phosphate, vitamins, minerals).
The
use of performance enhancing dietary supplements can be traced
back to the Romans who reportedly drank lion's blood to improve
their strength and courage. Today, unfortunately, nutritional
supplements are frequently promoted with unsubstantiated claims
so beware of the claims and of the Placebo Effect that you
can create.
(The
placebo affect results from our optimism and hope that a medication,
supplement, or training program will be beneficial, biasing us
toward a positive impression of the results.)
There
are few shortcuts for a well-designed training program supported
with sound nutrition. And although there may be little risk in
trying supplements in addition, there is a monetary cost for those
on a limited budget, as well as the potential to lose focus on
the real need for a good training program.
Following are a compilation of the main dietary supplements that
have been advocated as ergogenic aids over the last few years.
AMINO
ACIDS
Purified amino acids
(particularly arginine, ornitine, lysine, and tyrosine) have become
a popular, if expensive, form of protein supplementation. Five
well-performed studies have failed to demonstrate that either
singly, or in combination; there is any significant effect on
human growth hormone secretion or direct measures of muscular
development, strength, or power.
Amino
acids are the building blocks of proteins and are present in almost
all the foods we eat. As with vitamins, a balanced diet, which
replaces Caloric expenditures, should provide more than enough
of the essential amino acids. Amino acids sold in the health food
stores have no added advantage over a peanut butter sandwich and
a glass of milk, and don't have nearly the taste appeal.
Protein
should provide approximately 20% of our daily Caloric intake.
It normally provides less than 5% of the energy expended during
exercise and is used as a source of energy for normal cell functions
only during starvation or extreme malnutrition. Studies in athletes
have shown that 1.2 grams of protein per kilogram per day is adequate
for muscle development in most sports, and protein in excess of
2 grams per kilogram per day will be turned into fat. Most cyclists
get more than enough protein for cell building and repair from
the foods they eat, and any excess - whether from supplements
or in the diet - will be either converted to body fat or burned
inefficiently as fuel.
In addition, excess protein:
has
a diuretic effect increasing the risk of dehydration
can cause diarrhoea and abdominal bloating
may lead to chronic renal damage
can lead to gout
may increase total body calcium loss
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ANTI-INFLAMMATORIES
Common
wisdom holds that taking anti-inflammatory or aspirin before cycling
or other vigorous activity can reduce muscle soreness. However
one study concluded that even at large doses (20 mg per kg or
4 standard aspirin for the average rider), aspirin did not delay
the onset of muscle pain during exercise or reduce the perceived
intensity when it occurred. In addition there is good evidence
that using agents such as motrin (ibuprofen) or aspirin on a regular
basis increases the incidence of ulcers and can cause kidney and
liver damage. How much is too much? If it's a regular part of
your program, it's probably too much, and may be a sign that you
are riding or training too hard.
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ANTIOXIDANTS
There
is evidence supporting the long-term benefits of antioxidants.
However, short term studies are more controversial.
But at least one has suggested that the use of antioxidants in
the form of vitamins C, E, and beta carotene decreased muscle
damage in a group of runners as compared to a control group, and
there are numerous anecdotal reports that vitamin C taken before
a ride diminished the amount of muscle soreness the next day.
However, none have suggested a positive effect of any of the antioxidant
vitamins on actual exercise performance although one study from
the University of Birmingham did suggest that a group of riders
that took 500 mg of Vit C and exercised strenuously for 60 minutes,
recovered 85% of their muscle strength at 24 hours vs 75% in the
placebo group.
The
bottom line is that very little evidence to support the short-term
benefit of antioxidants for the competitive athlete - and plenty
of controversy remains as to the long-term health benefits. But
there is no evidence that they will do you any harm.
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ATP
(oral)
ATP
is the chemical compound that provides the energy for muscle action.
It is composed of a base (adenosine), a sugar (ribose) and three
phosphate groups. It is the high energy phosphate bonds that contains
the chemical energy which is stored in this molecule, and it is
the breaking of these bonds during cellular metabolism that power
muscle contractions and other vital cellular functions.
An
oral supplement of this compound is available. The only controlled
study available demonstrated a 7 % increase in mean power as demonstrated
by a Wingate performance test (a 30 second interval of maximal
performance, i.e. anaerobic, on a bicycle ergo meter) after taking
a 14-day supplement of 0.2 grams per kg body weight per day of
ATP-E. How this translates to improvement in actual cycling performance
or a positive impact on an end of race sprint is yet to be determined.
Until further studies confirm this preliminary impression, and
translate any benefits into actual improved cycling performance,
this supplement should be considered as unproven.
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ELECTROLYTES
The
minerals sodium, potassium, and chlorine are collectively referred
to as electrolytes. They are dissolved in the intra (within) and
extra (outside) cellular water as charged particles (ions) and
are responsible for maintaining a proper electrical gradient across
the cellular membrane - required for the proper functioning of
each cell.
A normal diet contains these three minerals in excess, and the
kidneys control the loss from the body. As a result there is no
requirement for diet supplementation except in extreme conditions.
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FAT(DIETARY)
Over
the last few years it has been suggested that a diet composed
of at least 30% fat Calories improves competitive aerobic performance
over a high carbohydrate diet - relatively restricted in fat Calories
(20-25%).
There
are a number of physiologic studies that demonstrate fat CANNOT
sustain high level (high VO2 max.) aerobic and anaerobic activity
(the cause of the "bonk" as glycogen stores are depleted).
And others that have shown that a high carbohydrate diet is best
for maintaining glycogen stores while a chronic deficit in replacing
carbohydrates has been proven to lead to chronic fatigue. In addition
it has been proven beyond any doubt that a long-term high fat
diet leads to heart disease. And for those who still aren't convinced,
it should be remembered that even the leanest athlete has plenty
of stored fat available without any need for diet supplements.
A
variation on this theme is reflected in the energy bars that contain
fat and are alleged to improve performance, SELECTIVELY increase
fat metabolism, and aid in weight loss. While there has been some
evidence that an occasional long slow recovery ride in your training
program MIGHT improve the ability to metabolise or use stored
fat Calories for muscle energy, there is no scientific basis for
the claims made by these products that eating any particular food
or food type (i.e. fat) will enhance fat metabolism.
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FIBRE
Fibre
is a general term for non-digestible carbohydrate in the diet
and refers mainly to the cellulose, lignin, and pectin found in
fruits, grains, and vegetables. Currently there is no recommended
minimum for dietary fibre and no special requirements for cyclists
or other athletes. On the other hand, there is good evidence that
too much fibre may bind minerals such as zinc in the intestinal
tract, resulting in poor absorption. A high fibre diet also may
lead to abdominal bloating and cramping. The most reasonable approach
seems to be a well balanced diet with enough fruits, grains, and
vegetables to maintain regular bowel function.
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GINSENGS
Ginsengs
are herbal preparations extracted from the roots of plants in
the family Araliaceae, and contain a wide variety of chemical
substances. Thus all ginsengs are not equivalent as far as ergogenic
potential. Some may work at the higher centres of the central
nervous system to enhance both mental and physical stamina.
A
commonly advertised commercial product, Ginsana, claims to produce
lower lactate levels and increase VO2 max. However, as with many
of the herbal products, there are as many studies supporting the
claims as refuting them - a common situation with ineffective
claims. And the most recent, which are the most carefully controlled,
failed to demonstrate any change in maximal aerobic performance
after two and three weeks of supplementation.
At
recommended doses, ginseng can produce the "ginseng abuse
syndrome" - high blood pressure, nervousness, and confusion.
Although this compound may be considered as "possibly"
effective, needing further study, try
it at your own risk!
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MINERALS
Minerals
are chemical elements found in the body either in their elemental
form or complexed with organic compounds. Like vitamins, they
are essential for normal cell functioning. The two most prevalent
minerals, calcium and phosphorus, are major components of bone
while sodium and potassium are found in all tissue fluids, both
within and around cells. Magnesium, chloride, sulphur, and zinc
are other minerals that play a key role in cell function. The
trace elements iron, manganese, copper, and iodine are found in
much smaller quantities, but play essential roles as catalysts
in basic cellular chemical processes.
These
minerals, found in all foods, are kept in balance through internal
regulation of absorption and excretion. As a result, adequate
tissue levels are easily provided by a balanced diet. Multiple
studies of body tissue mineral status in athletes failed to identify
any deficiencies in those ON A BALANCED DIET compared to people
engaged in normal daily activities. Athletes who are restricting
energy intake to achieve a lower body weight (endurance runners
for example) are the exception, and may need supplements.
It
has been alleged that athletes need higher than normal levels
of minerals to maintain maximum performance. However numerous
studies of mineral and micronutrient diet supplementation (with
the exception of iron in athletes who were clearly anaemic with
iron deficiency) have failed to demonstrate an improvement in
performance whenever studied.
Only
calcium (for long term bone strength) and iron (in clearly deficient
individuals) may be required by some athletes in increased amounts.
Because of toxic side effects when taken in large amounts, minerals
as a group are not recommended as routine supplements for athletes
on a balanced diet that meet their Caloric needs.
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OMEGA-3
FATTY ACIDS
These
"eicosanoids" are speculated to stimulate human growth
hormone release, and are marketed in several energy bars containing
a blend of fish and vegetable oils with omega3 fatty acids. There
is currently no support for an anabolic or performance enhancing
effect. Excesses may interfere with blood clotting.
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VITAMINS
Vitamins
are held up as a safe and effective way of improving performance.
Although coaches and trainers often recommend them, multiple studies
of body tissue vitamin status in athletes failed to identify any
specific deficiencies in those ON A BALANCED DIET (replacing Calories
expended) compared to people engaged in normal daily activities.
It
has been alleged that athletes need higher than normal levels
of vitamins to maintain maximum performance. Although supplementation
will improve corresponding blood levels of these vitamins, there
is NO evidence of improved performance.
There
is evidence that mega-vitamin programs can be harmful. The fat-soluble
vitamins (A, D, E, and K) are not eliminated in the urine and
can accumulate in body fat to reach toxic levels. And there have
been reports that even the water soluble ones (B complex, and
C which are excreted in the urine if excess amounts are taken)
can be harmful at doses of 10 to 100 times the recommended daily
requirements (RDA).
Vitamins
act as catalysts for the metabolic (biologic) pathways that convert
fats, carbohydrates, and proteins into Calories or energy. As
such, they facilitate the reaction, but are not "used up"
or consumed by it. This is why there is a single RDA that is independent
of body size, sex, or daily energy expenditures.
If
there is a concern about how your diet being well balanced, there
is no harm (other than to your wallet) in using a simple over
the counter multiple vitamin once a day. But vitamins are not
the easy answer to increased performance.
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