Amyotrophic lateral sclerosis (ALS) was made famous by Lou Gehrig,
the New York Yankees great whose baseball career was cut short in 1939.
Two years after calling himself the “luckiest man on the face of the
earth” at his tearful early retirement ceremony in Yankee stadium,
Gehrig died of the disease. Today, ALS is widely known as Lou Gehrig's
disease.
ALS is a degenerative neuromuscular disease that quickly progresses
and destroys nerve cells in the brain and spinal cord. This rapid
destruction soon begins to affect motor skills and basic movement while
preserving the mind and the ability to see, hear, touch, feel, and
taste. In Gehrig's case, it became obvious at the start of the 1939
season that the ballplayer was off his game, having trouble fielding
throws and running bases. Gehrig was benched in the beginning of the
season, never to play baseball again.
The loss of control Gehrig experienced is the hallmark of the
disease. ALS is characterized by symptoms such as tripping, clumsiness,
difficulty talking and slurred speech, muscle cramps, and twitching. In
its advanced stages, muscle wasting and atrophy set in. The most common
cause of death among ALS patients is respiratory failure or pulmonary
infection when the nerve damage eventually affects the muscles that
control breathing. The average survival time after diagnosis with ALS
is three to five years.
Scientists have struggled to identify the cause of ALS. To date, two
main forms of the disease have been identified: familial and sporadic.
Of these, sporadic ALS is by far the most common, accounting for about
90 percent of cases. Its cause is unknown, although researchers are
pursuing a number of theories, including oxidative stress, glutamate
toxicity, and mitochondrial dysfunction (Rowland L 1994; Cleveland DW
1999).
A number of other theories have been proposed, including autoimmune
disorders, heavy metal poisoning, and even viral infection, but much
more study is needed before these can be linked conclusively to ALS
(Mitchell J 2000). However, there is evidence that ALS may be caused by
poorly understood environmental factors. For example, the disease tends
to cluster in geographical pockets, yet so far researchers have been
stymied in their search for a common influence (Mitchell J 2000).
The second form of ALS, familial, is much more rare, occurring in
only 5 percent to 10 percent of cases. Approximately 20 percent of
familial ALS is caused by a genetic defect in an antioxidant enzyme
called superoxide dismutase-1, or SOD (Sung JJ et al 2002; Rosen DR et
al 1993). SOD's role in the body is to scavenge for unstable free
radical molecules. When this enzyme is deficient, as in ALS, a buildup
of free radicals may occur. The free radicals cause oxidative damage to
nerve cells, eventually destroying them.
Because of familial ALS's close association with free radical
damage, oxidative stress has emerged as a leading theory to explain
sporadic ALS. Free radicals are molecules that have an unpaired
electron. They can react with other molecules in the body that contain
oxygen, thereby creating reactive oxygen species such as nitric oxide
and the hydroxyl radical. Free radicals have been implicated in a large
number of diseases. They can be neutralized to some degree with
antioxidants such as vitamins C, E, or A; selenium; and coenzyme Q10.
It is important to understand, however, that free radical damage is
likely only one factor among many involved in ALS. In reality, ALS is
probably caused and aggravated by a number of conditions that work
together. By designing a careful regimen of nutrients and supplements,
individuals with ALS may be able to blunt the effects of individual
factors, thereby slowing the progression of the disease and lessening
its symptoms. Conventional medicine, which has fared poorly in treating
ALS, also attempts to lessen symptoms by slowing progression. Currently
only one drug is approved for ALS patients, and it has been shown to
extend life span by only two months (Lacomblez L et al 1996).
ALS remains relatively rare. It occurs in one to three people per
100,000 and tends to affect people between 30 and 60 years of age,
although it can occur in younger people. In the United States and
Europe, it affects men slightly more than women. In some parts of the
western Pacific (e.g., Guam), ALS is more common.
Possible Causes of ALS
To identify the underlying cause of sporadic ALS, a number of
scientific studies have examined various theories. A growing body of
evidence suggests that multiple, complicated factors may work together
to cause and advance ALS. Studies have also shown that many of these
factors are linked to underlying nutritional deficiencies that can be
addressed through diet and nutrient supplementation.
Oxidative damage. Free-radical nerve damage, which
can be caused by a defect in the SOD gene, has been implicated in
familial ALS. As free radicals build up as a result of a deficiency in
the antioxidant SOD, they assault and eventually destroy nerve cells.
Researchers have discovered that sporadic ALS patients have many of the
same underlying problems experienced by patients with familial ALS,
including abnormal protein aggregation, increased levels of calcium
between cells, and mitochondrial injury (Cameron A et al 2002). These
conditions contribute to neuronal death and muscle wasting common in
ALS.
Glutamate excitotoxicity. Glutamate is important to
proper brain function because of its role in communication between
neurons. Under normal conditions, its concentrations are tightly
regulated during its release into the extracellular space and its
reuptake into cells. In the case of stroke or seizure, however, excess
amounts of glutamate are released into the space between cells. This
excess glutamate can excite the nerve cells beyond their capacity and
result in nervecell death.
In ALS, there is evidence that the glutamate reuptake system may not
work correctly (Rothstein JD 1995), resulting in an accumulation of
glutamate in the space between cells (Cameron A et al 2002). The excess
glutamate allows more calcium to enter the cell. The interiors of
motor-neuron cells are highly sensitive to excess calcium, which
increases cell activity beyond normal levels (excitotoxicity) and
contributes to cellular injury through the production of free radicals.
A common approach in treating ALS is to decrease the level of
glutamate available in the body or to prevent cells from absorbing
excess glutamate. In fact, this is the therapeutic target of the only
drug approved by the Food and Drug Administration (FDA) for the
treatment of ALS. Dietary restrictions or supplements can be beneficial
in reducing glutamate excitotoxicity (Doble A 1999; Rothstein JD 1995;
Martin D et al 1993). Effective nutrients include pycnogenol, grape
seed extract, creatine, and alpha-lipoic acid. Each of these is
discussed in detail later in this chapter.
Mitochondrial abnormalities. The mitochondria are
the powerhouses, or energy factories, of cells. They are responsible
for many aspects of proper cellular function, including the production
of ATP, the scavenging of radical oxygen species, and the maintenance
of intracellular calcium concentrations. In ALS patients, changes in
mitochondria have been identified (Menzies FM et al 2002).
Mitochondrial abnormalities can directly lead to free radical
production or increased calcium levels between cells. Additionally,
because proper mitochondrial function is so essential, other processes,
as yet unidentified, could be altered when mitochondrial health is
impaired (Fosslien E 2001).
Supplements that support healthy mitochondrial function may help
stabilize mitochondrial health. Supplements that have been proven to
support the mitochondria include coenzyme Q10 (CoQ10), creatine, and
Ginkgo biloba.
Heavy metals and environmental agents. The role of
heavy metals in ALS is highly controversial. Because ALS tends to
cluster in certain geographical areas, such as a small town in
Wisconsin, researchers have searched for an underlying common theme,
including heavy-metal poisoning. So far, the results of these studies
have been conflicting and confusing. However, some studies have
connected ALS to environmental factors such as mercury (Mano Y et al
1990). Still other studies have been unable to prove a link between ALS
and any of the common heavy metals (Gresham LS et al 1986). The same
findings apply for environmental agents such as neurotoxic fertilizers
and pesticides. While there is good reason to think that neurotoxic
agents like these may be somehow linked to degenerative brain and nerve
conditions like ALS, researchers have so far been unable to meet the
demanding scientific standard needed to establish a causal relationship
(Caban-Holt A et al 2005).
Spreading Symptoms: The Onset and Conventional Treatment of ALS
Like many neuromuscular diseases, it can be difficult to make an
early diagnosis of ALS. Its symptoms vary from person to person,
depending on which group of muscles is affected first. A person can
notice tingling in the fingers or toes or cramping in the arms or legs
while stretching in bed, for example. There could be trouble with
tongue and facial movements, including chewing and swallowing.
As the disease progresses, it will move up the affected leg or arm
until eventually all muscle groups become involved. This spread into
all muscle groups is the defining characteristic of ALS. In fact, the
term amyotrophy refers to the atrophy (wasting) of muscle tissue, while
lateral sclerosis refers to the hardening of the spinal column from the
buildup of scar tissue (Rowland LP et al 2001).
Currently, only one drug, riluzole, has been approved by the FDA for
the treatment of ALS. Riluzole blunts the effects of glutamate by
decreasing glutamate release and blocking the ability of glutamate to
bind to its receptors, which decreases the excitotoxicity that leads to
cell death. It has been shown to prolong survival times in ALS patients
by approximately two months (Lacomblez L et al 1996). Albeit small,
this increase in survival time indicates that controlling glutamate
levels in the brain could be an essential component in fighting ALS,
and it provides valuable information toward ultimately finding a
treatment for the disease.
The rest of conventional medical treatment for ALS focuses on
improving quality of life for ALS patients. Physicians frequently
recommend prescription medications to relieve painful muscle cramps,
excessive salivation, and other symptoms. ALS patients are often
advised to engage in moderate exercise to maintain muscle strength and
function, and to seek physical therapy. As the disease progresses,
splints, braces, and wheelchairs are used to help with mobility.
Occupational and speech therapy also helps patients as their motor
control gradually deteriorates.
Are Stem Cells the Great Hope for Curing ALS?
One of the most exciting areas of research into ALS is stem cell
therapy. Stem cells, which are immature cells that can differentiate
into specialized adult cells, could represent the next great advance
for ALS therapy.
Because of federal restrictions on stem cell therapy and the
difficulty of designing studies, very few studies have been conducted
so far on the treatment of ALS with stem cells. The ones that have been
conducted, however, are encouraging, and early animal results show
great promise. Researchers have found the following:
- Stem cells delayed motor neuron degeneration in mouse models of ALS (Salini V et al 2004).
- Bone-marrow-derived stem cells injected into human ALS patients were safe (Silani V et al 2004).
Even as researchers push forward with a promising study of stem
cells in ALS, there is an understanding that antioxidant therapy will
remain an important part of ALS therapy (Silani V et al 2004).
Attacking ALS with Nutrition
There is no question that adequate nutrition is crucial to survival
for ALS patients. As the disease progresses, patients gradually lose
the ability to chew or swallow easily. At the same time, the abdominal
and pelvic muscles weaken, and depression frequently sets in. Patients
often lose the ability and desire to eat, and malnutrition is a common
problem (Cameron A et al 2002).
Unfortunately, the lack of adequate nutrition is especially
dangerous for ALS patients. An ALS patient's increased efforts to
breathe can result in a greater metabolic rate and the need for a
higher caloric intake. Inadequate nutrition can further accelerate the
breakdown of muscle tissue and weaken the immune system. This can lead
to infection, which is a common cause of death in ALS patients (Aldrich
TK 1993).
Studies have consistently indicated that the use of nutrient
supplements and antioxidants help ALS patients reduce symptoms and
maintain quality of life (Cameron A et al 2002). The following
sections, based on Life Extension's survey of the literature, highlight
evidence supporting various promising supplements.
Vitamins and Minerals: The First Line of Defense
Vitamin B12 (methylcobalamin). Ultrahigh doses of
vitamin B12 (25 mg) have been shown to improve or slow muscle wasting,
which is common among ALS patients in the later stages of the disease
(Kaji R et al 1998).
Vitamin E. Vitamin E has attracted significant
attention from ALS researchers as a result of its antioxidant
properties. Vitamin E protects cell membranes against a process known
as lipid peroxidation (Cameron A et al 2002). Lipid peroxidation is the
breakdown of the cell membrane, which could play a role in degenerative
diseases such as ALS. A recent study in humans indicated that vitamin E
can help prevent ALS because of its antioxidant properties (Ascherio A
et al 2005)).
Zinc. Zinc is an important mineral involved in many
physiological processes. During periods of oxidative stress, changes in
zinc metabolism that lead to neurodegeneration can occur (Cuajungco MP
et al 1997). Furthermore, mutations in the SOD enzyme that decrease its
ability to bind to zinc have been demonstrated and may lead to ALS
(Banci L et al 2002). However, a study conducted at the Linus Pauling
Institute found that large doses of zinc inhibit copper absorption. In
the study, researchers added a small dose of copper to animal ALS
models receiving zinc (.3 mg/kg/day of copper with 18 mg/kg/day of
zinc) and found the copper prevented early death associated with high
doses of zinc (Ermilova IP et al 2005)
Herbal Supplements
Ginseng. In an animal model of ALS, ginseng was
shown to significantly delay the onset of ALS symptoms (Jiang F et al
2000). This was likely due to its antioxidant properties. For more
information about the safety profile of ginseng, see “Safety Caveats”
at the end of this chapter.
Ginkgo biloba. Ginkgo biloba also
has antioxidant properties (Ernst E 2002). Additionally, Ginkgo biloba
has been shown to promote healthy mitochondrial function (Fosslien E
2001), and during an in vitro study, it was found to protect against
glutamate-induced excitotoxicity (Kobayashi MS et al 2000). In animal
studies, Ginkgo biloba also limited weight loss among female models for
ALS (Ferrante RJ et al 2001).