Creatine: More than a sports nutrition
supplement
by Will Brink
Although creatine offers an
array of benefits, most people think of it simply as a
supplement that bodybuilders and other athletes use to gain
strength and muscle mass. Nothing could be further from the
truth.
A substantial body of research has found that creatine may have
a wide variety of uses. In fact,
creatine is being studied as a supplement that may help with
diseases affecting the neuromuscular system, such as muscular
dystrophy (MD).
Recent studies suggest creatine may have therapeutic
applications in aging populations for wasting syndromes, muscle
atrophy, fatigue, gyrate atrophy, Parkinson's disease,
Huntington's disease and other brain pathologies. Several
studies have shown creatine can reduce cholesterol by up to 15%
and it has been used to correct certain inborn errors of
metabolism, such as in people born without the enzyme(s)
responsible for making creatine.
Some studies have found that creatine may increase growth
hormone production.
What is creatine?
Creatine is formed in the human body from the amino acids
methionine, glycine and arginine. The average person's body
contains approximately 120 grams of creatine stored as creatine
phosphate. Certain foods such as beef, herring and salmon, are
fairly high in creatine.
However, a person would have to eat pounds of these foods daily
to equal what can be obtained in one teaspoon of powdered
creatine.
Creatine is directly related to adenosine triphosphate (ATP).
ATP is formed in the powerhouses of the cell, the mitochondria.
ATP is often referred to as the "universal energy molecule"
used by every cell in our bodies. An increase in oxidative
stress coupled with a cell's inability to produce essential
energy molecules such as ATP, is a hallmark of the aging cell
and is found in many disease states.
Key factors in maintaining health are the ability to: (a)
prevent mitochondrial damage to DNA caused by reactive oxygen
species (ROS) and (b) prevent the decline in ATP synthesis,
which reduces whole body ATP levels. It would appear that
maintaining antioxidant status (in particular intra-cellular
glutathione) and ATP levels are essential in fighting the aging
process.
It is interesting to note that many of the most promising
anti-aging nutrients such as CoQ10, NAD, acetyl-l-carnitine and
lipoic acid are all taken to maintain the ability of the
mitochondria to produce high energy compounds such as ATP and
reduce oxidative stress.
The ability of a cell to do work is directly related to its ATP
status and the health of the mitochondria. Heart tissue,
neurons in the brain and other highly active tissues are very
sensitive to this system. Even small changes in ATP can have
profound effects on the tissues' ability to function
properly.
Of all the nutritional supplements available to us currently,
creatine appears to be the most effective for maintaining or
raising ATP levels.
How does creatine work?
In a nutshell, creatine works to help generate energy. When ATP
loses a phosphate molecule and becomes adenosine diphosphate
(ADP), it must be converted back to ATP to produce energy.
Creatine is stored in the human body as creatine phosphate (CP)
also called phosphocreatine.
When ATP is depleted, it can be recharged by CP. That is, CP
donates a phosphate molecule to the ADP, making it ATP again.
An increased pool of CP means faster and greater recharging of
ATP, which means more work can be performed.
This is why creatine has been so successful for athletes. For
short-duration explosive sports, such as sprinting, weight
lifting and other anaerobic endeavors, ATP is the energy system
used.
To date, research has shown that ingesting creatine can
increase the total body pool of CP which leads to greater
generation of energy for anaerobic forms of exercise, such as
weight training and sprinting. Other effects of creatine may be
increases in protein synthesis and increased cell
hydration.
Creatine has had spotty results in affecting performance in
endurance sports such as swimming, rowing and long distance
running, with some studies showing no positive effects on
performance in endurance athletes.
Whether or not the failure of creatine to improve performance
in endurance athletes was due to the nature of the sport or the
design of the studies is still being debated.
Creatine can be found in the form of creatine monohydrate,
creatine citrate, creatine phosphate, creatine-magnesium
chelate and even liquid versions.
However, the vast majority of research to date showing creatine
to have positive effects on pathologies, muscle mass and
performance used the monohydrate form. Creatine monohydrate is
over 90% absorbable. What follows is a review of some of the
more interesting and promising research studies with
creatine.
Creatine and neuromuscular diseases
One of the most promising areas of research with creatine is
its effect on neuromuscular diseases such as MD. One study
looked at the safety and efficacy of creatine monohydrate in
various types of muscular dystrophies using a double blind,
crossover trial.
Thirty-six patients (12 patients with facioscapulohumeral
dystrophy, 10 patients with Becker dystrophy, eight patients
with Duchenne dystrophy and six patients with
sarcoglycan-deficient limb girdle muscular dystrophy) were
randomized to receive creatine or placebo for eight weeks.
The researchers found there was a "mild but significant
improvement" in muscle strength in all groups. The study also
found a general improvement in the patients' daily-life
activities as demonstrated by improved scores in the Medical
Research Council scales and the Neuromuscular Symptom scale.
Creatine was well tolerated throughout the study period,
according to the researchers.1
Another group of researchers fed creatine monohydrate to people
with neuromuscular disease at 10 grams per day for five days,
then reduced the dose to 5 grams per day for five days.
The first study used 81 people and was followed by a
single-blinded study of 21 people.
In both studies, body weight, handgrip, dorsiflexion and knee
extensor strength were measured before and after treatment. The
researchers found "Creatine administration increased all
measured indices in both studies." Short-term creatine
monohydrate increased high-intensity strength significantly in
patients with neuromuscular disease.2
There have also been many clinical observations by physicians
that creatine improves the strength, functionality and
symptomology of people with various diseases of the
neuromuscular system.
Creatine and neurological protection/brain injury
If there is one place creatine really shines, it's in
protecting the brain from various forms of neurological injury
and stress. A growing number of studies have found that
creatine can protect the brain from neurotoxic agents, certain
forms of injury and other insults.
Several in vitro studies found that neurons exposed to either
glutamate or beta-amyloid (both highly toxic to neurons and
involved in various neurological diseases) were protected when
exposed to creatine.3 The researchers hypothesized that "?
cells supplemented with the precursor creatine make more
phosphocreatine (PCr) and create larger energy reserves with
consequent neuroprotection against stressors."
More recent studies, in vitro and in vivo in animals, have
found creatine to be highly neuroprotective against other
neurotoxic agents such as N-methyl-D-aspartate (NMDA) and
malonate.4 Another study found that feeding rats creatine
helped protect them against tetrahydropyridine (MPTP), which
produces parkinsonism in animals through impaired energy
production.
The results were impressive enough for these researchers to
conclude, "These results further implicate metabolic
dysfunction in MPTP neurotoxicity and suggest a novel
therapeutic approach, which may have applicability in
Parkinson's disease."5 Other studies have found creatine
protected neurons from ischemic (low oxygen) damage as is often
seen after strokes or injuries.6
Yet more studies have found creatine may play a therapeutic and
or protective role in Huntington's disease7, 8 as well as ALS
(amyotrophic lateral sclerosis).9 This study found that "? oral
administration of creatine produced a dose-dependent
improvement in motor performance and extended survival in G93A
transgenic mice, and it protected mice from loss of both motor
neurons and substantia nigra neurons at 120 days of age.
Creatine administration protected G93A transgenic mice from
increases in biochemical indices of oxidative damage.
Therefore, creatine administration may be a new therapeutic
strategy for ALS." Amazingly, this is only the tip of the
iceberg showing creatine may have therapeutic uses for a wide
range of neurological disease as well as injuries to the
brain.
One researcher who has looked at the effects of creatine
commented, "This food supplement may provide clues to the
mechanisms responsible for neuronal loss after traumatic brain
injury and may find use as a neuroprotective agent against
acute and delayed neurodegenerative processes."
Creatine and heart function
Because it is known that heart cells are dependent on adequate
levels of ATP to function properly, and that cardiac creatine
levels are depressed in chronic heart failure, researchers have
looked at supplemental creatine to improve heart function and
overall symptomology in certain forms of heart disease.
It is well known that people suffering from chronic heart
failure have limited endurance, strength and tire easily, which
greatly limits their ability to function in everyday life.
Using a double blind, placebo-controlled design, 17 patients
aged 43 to 70 years with an ejection fraction <40 were
supplemented with 20 grams of creatine daily for 10 days.
Before and after creatine supplementation, the researchers
looked at:
1) Ejection fraction of the heart (blood present in the
ventricle at the end of diastole and expelled during the
contraction of the heart)
2) 1-legged knee extensor (which tests strength)
3) Exercise performance on the cycle ergometer (which tests
endurance)
Biopsies were also taken from muscle to determine if there was
an increase in energy-producing compounds (i.e., creatine and
creatine phosphate). Interestingly, but not surprisingly, the
ejection fraction at rest and during the exercise phase did not
increase.
However, the biopsies revealed a considerable increase in
tissue levels of creatine and creatine phosphate in the
patients getting the supplemental creatine. More importantly,
patients getting the creatine had increases in strength and
peak torque (21%, P < 0.05) and endurance (10%, P <
0.05).
Both peak torque and 1-legged performance increased linearly
with increased skeletal muscle phosphocreatine (P < 0.05).
After just one week of creatine supplementation, the
researchers concluded: "Supplementation to patients with
chronic heart failure did not increase ejection fraction but
increased skeletal muscle energy-rich phosphagens and
performance as regards both strength and endurance.
This new therapeutic approach merits further attention."10
Another study looked at the effects of creatine supplementation
on endurance and muscle metabolism in people with congestive
heart failure.11 In particular the researchers looked at levels
of ammonia and lactate, two important indicators of muscle
performance under stress.
Lactate and ammonia levels rise as intensity increases during
exercise and higher levels are associated with fatigue.
High-level athletes have lower levels of lactate and ammonia
during a given exercise than non-athletes, as the athletes'
metabolism is better at dealing with these metabolites of
exertion, allowing them to perform better.
This study found that patients with congestive heart failure
given 20 grams of creatine per day had greater strength and
endurance (measured as handgrip exercise at 25%, 50% and 75% of
maximum voluntary contraction or until exhaustion) and had
lower levels of lactate and ammonia than the placebo group.
This shows that creatine supplementation in chronic heart
failure augments skeletal muscle endurance and attenuates the
abnormal skeletal muscle metabolic response to exercise.
It is important to note that the whole-body lack of essential
high energy compounds (e.g. ATP, creatine, creatine phosphate,
etc.) in people with chronic congestive heart failure is not a
matter of simple malnutrition, but appears to be a metabolic
derangement in skeletal muscle and other tissues.
Supplementing with high energy precursors such as creatine
monohydrate appears to be a highly effective, low cost approach
to helping these patients live more functional lives, and
perhaps extend their life spans.
Conclusion
Creatine is quickly becoming one of the most well researched
and promising supplements for a wide range of diseases. It may
have additional uses for pathologies where a lack of high
energy compounds and general muscle weakness exist, such as
fibromyalgia.
People with fibromyalgia have lower levels of creatine
phosphate and ATP levels compared to controls.13 Some studies
also suggest it helps with the strength and endurance of
healthy but aging people as well.
Though additional research is needed, there is a substantial
body of research showing creatine is an effective and safe
supplement for a wide range of pathologies and may be the next
big find in anti-aging nutrients.
Although the doses used in some studies were quite high, recent
studies suggest lower doses are just as effective for
increasing the overall creatine phosphate pool in the body.
Two to three grams per day appears adequate for healthy people
to increase their tissue levels of creatine phosphate. People
with the aforementioned pathologies may benefit from higher
intakes, in the 5-to-10 grams per day range.
About the Author
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