The essential branched chain amino acids (BCAA's)
include leucine, isoleucine, and valine are of special importance
for athletes because they are metabolized in the muscle, rather
than in the liver (26). Theoretically, after digestion, once
protein is broken down into individual amino acids, these amino
acids can either be used to build new proteins or be burned as
fuel to produce energy. If the athlete's diet is adequate in
nutrition, then the above "essential" amino acids will
be used for protein synthesis which is optimal for advanced human
performance. It should also be noted that, essential amino acids
are not produced in the body such as non-essential amino acids,
but rather obtained through proper nutrition. Therefore, it is
often theorized that the supplementation of BCAA's are of essential
importance to athletes due to their ability to alleviate any
deficiencies that the body alone cannot produce. BCAA's have
also been known in reducing fatigue in both anaerobic and endurance
sports. It has also been noted that leucine may be the most critical
BCAA because of its anti-catabolic properties and vital role
in protein synthesis (83).
BCAA's have a great deal of thorough and conclusive research
surrounding them. Although there are a few studies which show
mixed results, it should be noted that most studies seem quite
favorable in regards to the supplementation with BCAA's. In a
study performed by Ohtani et al (27), the results showed that
the subjects who received BCAA's had a significant increase in
exercise efficiency due to the heightened levels of aerobic and
anaerobic capacity as compared to the placebo group.
Other studies of similar characteristics of supplementing with
BCAA's have also been consistent with the above results. For
example, in another study performed by Ohtani et al (29), a thorough
before and after analysis concluded that markers for physical
conditioning, fitness, and endurance greatly improved. In fact,
only 2.2 g of the amino acid mixture three times a day significantly
improved other physiological markers such as: red blood cell
count, hemoglobin, hematocrit, serum albumin, fasting glucose,
and a decrease in creatine phophokinase (p<0.05), suggesting
increased hematopoiesis and glycogenesis, and rapid alleviation
of muscle inflammation by the amino acid mixture. All of these
beneficial factors may be of huge significance in high performance
athletes especially in terms of overall conditioning.
Another study by Sugita et al (28) demonstrated the effect of
an amino acid mixture, mainly consisting of BCAA's on recovery
from muscle fatigue and damage after eccentric exercise training.
Twenty-two male college students were given 5.6 grams of the
amino acid mixture twice daily which resulted in a faster recovery
of muscle strength than that of the placebo group. The oral ingestion
of the amino acid mixture was proved to be effective for muscle
strength recovery after the eccentric exercise.
Perhaps, one of the most profound studies on amino acid supplementation
to date was done by Kraemer et al (30) in which 17 trained men
randomly assigned to either an amino acid group or a placebo
group underwent a 4 week training routine of total body resistance
training. The first two weeks of training was an overreaching
stage in which the total volume of training was relatively high
which was then followed by a two week period of tapering or less
total volume. Before any of the training took place, there were
baseline measurements taken to determine strength, such as 1RM
bench press and squat as well as a ballistic bench press and
jump squat to determine power output.
The results in this study were quite interesting. First of all,
it appears that both groups had significant increases in strength,
power, and resistance to fatigue after the entire four week period
which can be attributed to the training program. This would support
the fact that overreaching can be very beneficial to athletes
trying to improve performance. However, the interesting results
show that the placebo group experienced significant decreases
in strength in the first 2 weeks of the training program where
the subjects were in a stage of overreaching. However, the amino
acid group did not have any change in performance during this
period. This was obviously due to the anti-catabolic effects
that BCAA's promote in the body. Thus, for athletes interested
in peaking performance, through the use of strenuous and intense
exercise where initial decrements of performance can occur, these
negative symptoms can be regulated and possibly negated by the
supplementation of BCAA's.
BCAA's have a positive effect on reducing fatigue and help in
maintaining plasma levels of BCAA's in the body. Coombes et al
(84) examined the effects of branched-chain amino acid (BCAA)
supplementation on serum indicators of muscle damage after long
periods of exercise. They hypothesized that BCAA supplementation
would reduce serum indicators of muscle damage. There were 16
healthy males randomly assigned to either an experimental group
in which they supplemented with 12 grams of BCAA's a day or a
control/placebo group. Both groups participated in a two hour
cycling activity at an intensity of 70% VO2. The results of this
study clearly show that BCAA supplementation played a significant
role in reducing levels of plasma markers associated with muscle
tissue damage after intense endurance exercise. Of further interest,
there have been many other studies similar to this in which plasma
levels of specific compounds indicating muscle damage were reduced
with BCAA supplementation. Low amounts of BCAA plasma levels,
specifically leucine, have been correlated with increased levels
of fatigue and reduced markers of physical performance (85).
Another interesting function of BCAA's is their profound effect
on clinically diagnosed patients with specialized diseases or
health problems. First, BCAA's may support liver health in patients
with liver disease (31). Also, patients suffering from amyotrophic
lateral sclerosis, or ALA, may show improvement after using BCAA's
(32). Third, BCAA's may help support health and recovery in patients
who have experienced trauma, extreme physical stress, kidney
failure, and burns (33). Finally, BCAA's may aid in recovery
after surgery (34).
Dosage recommendations for BCAA's vary widely and more research
is needed before finalization is made for the best supplementation
dosage of BCAA's. However, the most recent research indicates
that dosages typically range from 200-300mg of each BCAA daily
to 2-5 grams of each daily. It however seems that the smallest
beneficial dosage of BCAA's is 150mg of each leucine, isoleucine,
and valine daily (35).
Summary and Recommendation
Although there may be slight contradictions in pre-existing
research regarding BCAA supplementation, there is enough positive
scientific evidence to warrant its usage in high performance
athletes. From numerous studies, it is clear that BCAA's have
a significant role in increasing overall conditioning factors
such as aerobic and anaerobic capacities, by improving physiological
markers such as: red blood cell count, hemoglobin, hematocrit,
serum albumin, fasting glucose levels, a decrease in creatine
phophokinase, increased glycogenesis, and even rapid alleviation
of muscle inflammation. Other positive attributes associated
with BCAA's as shown by current scientific literature includes:
increased muscle recovery, especially after intense eccentric
exercise, alleviation of short term decrements in performance
commonly associated with overreaching, improvements in plasma
levels of BCAA's (often linked with fatigue), and may aid in
the healing of injuries, sickness, and trauma. There may also
be strength and muscle mass increases accompanied by BCAA supplementation.
However, further research is needed to determine whether this
is a direct or indirect effect of BCAA supplementation.
According to consumerlab.com, there is no apparent toxicity or
danger associated with BCAA supplementation. ConsumerLab also
recommends anywhere from 1-12 grams. The typical ratio of BCAA's
is 50% leucine, 25% isoleucine, and 25% valine. This also lines
up with the most current research on BCAA supplementation. BCAA's
should be taken with water before and after training with any
other pre or post workout supplement.
According to consumerlab.com and other valid sources, some of
the best BCAA products include: Iron-Tech, Essential Liquid Amino
Complex, AST BCAA, MRM BCAA+G, Precision Engineered BCAA, Beverly
International Muscularity, Optimum Nutrition BCAA, Controlled
Labs Purple Wraath, and Ultimate Nutrition BCAA.
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28. Sugita M, Ohtani M, Ishii N, Maruyama K, Kobayashi K.
Effect of a selected amino acid mixture on the recovery from
muscle fatigue during and after eccentric contraction exercise
training. Biosci Biotechnol Biochem. 2003 Feb;67(2):372-5.
29. Ohtani M, Maruyama K, Suzuki S, Sugita M, Kobayashi K.
Changes in hematological parameters of athletes after receiving
daily dose of a mixture of 12 amino acids for one month during
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French DN, Gomez AL, McGuigan MR, Scheett TP, Newton RU, Spiering
BA, Izquierdo M, Dioguardi FS. The effects of amino acid supplementation
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