Sports
Nutrition Update -- Abstracts from the American College of Sports Medicine
43rd Annual Meeting
G.
Douglas Andersen, DC, DACBSP, CCN
Volume
15, number 5, 2/24/97, page 14
Ergogenic aids, antioxidants, chromium, creatine, inosine, and branchchain
amino acids.
Part II: Ergogenic Aids
Editor's note: Part I of Dr. Andersen's article was published in the
1/27/97 issue of DC.
Antioxidants
Sixteen males, ages 18-34, who ran an average of 20 to 25 miles per week,
were tested on a 30 minute run at 80% V02 max, followed by a sprint to
exhaustion (this is a hard workout). They were fed an energy bar rich
in antioxidants (vitamin C, vitamin E, and mixed carotenoids), or an identical
tasting placebo. Testing before and after exercise revealed increases
in the activities of oxidant defense enzyme systems which resulted in
a lower level of oxidative stress when athletes ate the antioxidant energy
bar.1
Comment: Athletes need extra antioxidants above
RDA levels. With such an incredibly safe risk-benefit ratio, it is my
opinion that those people who are against nutritional supplements for
athletes must prove scientifically that the RDAs are optimal for heavy
exercisers. Until that happens, I will continue to recommend that anyone
involved in athletic activity on a regular basis supplement his or her
diet with antioxidants.
Branch Chain Amino Acids
There have been a lot of conflicting studies on amino acids. Many of the
more recent ones have been negative concerning the ergogenic effects of
amino acid supplementation. In this double-blind, placebo-controlled study
six male subjects consumed a branch chain amino acid mixture or placebo.
They then performed eccentric leg extension exercises. Muscle biopsies
and blood tests were taken during and after exercise. Calorie intake was
controlled and the trials were separated by 30 days. The authors concluded
that oral ingestion of branch chain amino acids elevated branch chain
amino acids during exercise and recovery, and suppressed the rate of net
muscle protein degradation.2
In a study on female college students, 30 minutes prior to exercise tests
they took either 11 gm of branch chain amino acid formula or a placebo
in a double-blind manner. During all prolonged exercise tests, blood lactate
levels were significantly lower in the branch chain amino acid group,
and blood ammonia levels were higher in the amino acid group, which the
authors state may imply an increased branch chain amino acid utilization.
The rate of perceived exertion levels was significantly lower when athletes
took branch chain amino acids (i.e., athletes did not feel as tired when
they supplemented with BCAAs). The authors stated that branch chain amino
acids may improve exercise endurance capacity and the rate of perceived
exertion during prolonged exercise of moderate intensity despite the accumulation
of ammonia.3
Comment: What these abstracts show me is that
amino acid supplementation can work if enough is taken. In the first study,
the amount of amino acids given was seven doses of 38.5 mg/kg of body
weight, which for a 154 pound male equates to almost 19 gm. In the latter
study, the women were ingesting 11 gm of branch chain amino acids. When
you go to the health food store and read labels on amino acid products,
you will find that the amounts recommended are not close to the amounts
used in the above trials.
Furthermore, many of the studies that have been performed on amino acids
without favorable results have used levels that are recommended on product
labels. It is my opinion that branch chain amino acids can help build
muscle and aid in recovery, but they must be dosed in levels (e.g., 2.5
gm seven times a day) that even the most compliant person will have difficulty
following on a regular basis.
Creatine
This double-blind study showed that creatine supplementation at the rate
of 25 gm per day for seven days resulted in a significant improvement
in power output for the bench press and jump squat. Creatine ingestion
for one week also increased lean body mass in spite of no change in dietary
energy intake. The authors feel this indicates that creatine monohydrate
supplementation can increase body mass and enhance muscular performance.4
In a double-blind, placebo-controlled trial, college-age men and women
consumed 5 gm of creatine monohydrate four times a day for four days and
then were tested for a 30 second sprint on an exercise bike. Total muscle
creatine was increased but performance was not. The authors concluded
that creatine supplementation did not improve performance during a single
30 second exercise bout.5
Twelve male runners ingested 20 gm of creatine monohydrate or a placebo
for five days. They were then tested in maximal running bouts lasting
no longer than two minutes. The authors concluded that the creatine supplementation
did not enhance performance in this test.6
Comment: There is an increasing amount of literature
as well as thousands of anecdotal reports that creatine increases size
and strength in the weight room. In the first study, the mass gain with
no increase in calories supports the cell volumizing theory of creatine
monohydrate, i.e., when a cell is loaded with creatine, the creatine attracts
excess fluid. When muscles are hyperhydrated they are bigger and stronger.
In my opinion creatine is not the supplement of choice for endurance athletes,
however, for anaerobic athletes such as sprinters, creatine supplementation
may be of benefit. Although the second and third studies were negative,
the creatine was only given for a one week period. We have learned that
at the end of a week of supplementation with steroids a person may be
stronger in an exercise like the bench press, but it will take longer
to affect performance in activities such as sprinting. If creatine can
help build muscle size and power, which the weightlifting studies support,
I expect that athletes in explosive sports will also benefit from creatine
use with properly designed studies science should validate this.
Chromium Picolinate
Chromium picolinate supplementation for weight loss and lean body mass
has been controversial in the literature with some initial studies showing
promise and most of the recent studies being negative. In this very interesting
study (double blind, placebo controlled) of 40 collegiate swimmers during
the competitive season, 24 weeks of supplementation with 400 mcg of chromium
picolinate increased lean body mass (3.3%), decreased fat mass (4.6%),
and decreased body fat (6.43%). Females lost more body fat (8.2%) than
males (4.6%), but the authors speculate that the greater loss of body
fat for the women may have been because they had more body fat to begin
with. What was most interesting in the study was the greatest rate of
change for both males and females in body composition occurred between
weeks 12 and 24.7
Comment: The authors suggest that the effectiveness
of chromium picolinate may require a longer supplementation period than
has been routinely used in previous studies, and also may work better
with higher intensity exercise as was the case in this study. This abstract
was certainly impressive. I hope to see it published and, if replicated,
will certainly rehabilitate what in my opinion has been a tarnished image
with chromium picolinate due to a host of less than impressive studies
over the past couple of years.
Inosine
Inosine is an ergogenic aid that purportedly increases 2-3 diphosphoglycerate
concentration in the blood, thus increasing oxygen to the tissues, which
results in greater performance. In this test subjects were given 5,000
mg a day of inosine or a placebo. Competitive male cyclists either rode
30 minutes (self-paced), or rode in a supramaximal sprint to exhaustion
trial. In the 30-minute test there was no difference in the amount of
work produced, but in the sprint test the inosine group fatigued more
rapidly than the placebo group.8
Comment: Inosine was a hot ergogenic aid in the late 1980s and early 1990s.
Its popularity faded in recent years. In this study the inosine was actually
ergolytic, i.e., supplementation hurt performance. Although one abstract
does certainly not indicate a paradigm shift, I would like to see those
companies who market inosine fund further studies on this supplement.
I am sure if inosine is proven to be ergolytic that responsible marketers
and business people would cease selling this product as a performance
enhancer.
References
1. Applegate L, Camplen L, et al. Influence of an antioxidant nutrient-fortified
food product and strenuous exercise on antioxidant enzyme systems. S30.
176.
2. MacLean D, Kiens B, et al. Branch chain amino acid supplementation
reduces muscle amino acid release after eccentric exercise. S181. 1079.
3. Nemoto I, Tanaka A, Kuroda Y. Branch chain amino acid supplementation
improved endurance capacities and rate of perceived exertion. S37. 219.
4. Volek J, Kraemer W et al. Creatine supplementation: effects on muscular
performance during high intensity resistance exercise. S81. 482.
5. Rudin T, Parcell A. Effects of oral creatine supplementation on performance
of muscle metabolism during maximal exercise. S81. 484.
6. Terrillion K, Dolgener F. Effect of creatine supplementation on two
700 meter maximal running bouts. S36. 215.
7. Bulbulian R, Pringle D, Liddy M. Chromium picolinate supplementation
in male and female swimmers. S111. 684.
8. Starling R, Trappe T et al. Effect of inosine supplementation on aerobic
and anaerobic cycling performance. S82. 487.
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