Parkinsons disease is a chronic disorder typically affecting people over age
55. The condition is caused by the death of nerve cells in certain parts of the
brain, leading to characteristic problems with movement. These include a "pill
rolling" tremor in the hands (so called because it appears that the individual
is rolling a small object between thumb and forefinger), difficulty initiating
walking, a shuffling gait, decreased facial expressiveness, and trouble talking.
Thinking ability may become impaired in later stages of the disease, and
depression is common.
Although the underlying cause of Parkinsons disease is unknown, many
researchers believe that free radicals may play a role in destroying at least
some of the nerve cells. Large population studies provide some indications that
people with higher intakes of antioxidants, which neutralize free radicals, may
have lower rates of the disease. However, the results of these population
studies are inconsistent: one study of 41,836 older women found that among the
antioxidants studied, only vitamin C and manganese were linked to lower rates of
Parkinsons disease—while intake of vitamin E, for example, seemed unrelated. In
contrast, a smaller study of 5,342 older people found that individuals who
consumed more vitamin E had a lower incidence of Parkinsons disease, but
vitamin C and other antioxidants seemed unrelated.2 Obviously, more research is
needed.
The nerve cells that are affected in Parkinsons disease work by supplying
dopamine, a neurotransmitter, to another part of the brain. Most treatments for
Parkinsons disease work by artificially increasing the brains dopamine levels.
Simply taking dopamine pills wont work, however, because the substance cannot
travel from the bloodstream into the brain. Instead, most people with
Parkinsons disease take levodopa (L-dopa), which can pass into the brain and be
converted there into dopamine. Many people take levodopa with carbidopa, a drug
that increases the amount of levodopa available to make dopamine.
At first, levodopa produces dramatic improvement in symptoms; however, over
time, levodopa becomes less effective and more likely to produce side effects.
Other drugs may be tried, including bromocriptine, selegiline, and pergolide.
There are also surgical treatments, such as pallidotomy, that can decrease
symptoms.
Treatment
Principal Proposed Treatments for Parkinsons Disease:
Most research into natural treatments has focused on one of three goals:
reducing the presence of free radicals in the brain in an effort to preserve
dopamine-producing cells, enhancing the effects of levodopa or
naturally-occurring dopamine, or treating the mental symptoms that sometimes
accompany advanced Parkinsons disease. So far, the most useful natural
treatment appears to be CDP-choline, a dietary supplement that may enhance
levodopas effectiveness.
CDP-Choline
Short for cytidinediphosphocholine, CDP-choline (sometimes called citicholine)
is a substance that occurs naturally in the human body. It is closely related to
choline, a nutrient commonly put in the B-vitamin family. Evidence suggests that
CDP-choline may enhance the effects of levodopa and decrease some symptoms of
Parkinsons disease.
For reasons that are not completely clear, CDP-choline seems to increase the
amount of dopamine in the brain. Most studies investigating this in people with
Parkinsons disease have used intravenous or intramuscular injections of
CDP-choline. However, in one study, CDP-choline was taken in oral form.
What Is the Scientific Evidence for CDP-Choline?
In a 4-week single-blind study of 74 people with Parkinsons disease,
researchers tested whether oral CDP-choline might help levodopa be more
effective.5 Researchers divided participants into two groups: one group received
their usual levodopa dose, the other received half their usual dose without
knowing which dosage they were getting. All the participants took 1,200 mg a day
of oral CDP-choline.
Even though 50% of the participants were taking only half their usual dose of
levodopa, both groups scored equally well on standardized tests designed to
evaluate the severity of Parkinsons disease symptoms.
A number of other single- and double-blind studies have found that intravenous
or intramuscular injections of CDP-choline either reduced symptoms of
Parkinsons disease or allowed decreased doses of levodopa without loss of
effectiveness.
Dosage
In the study of oral CDP-choline described above, participants took 400 mg of
CDP-choline 3 times a day.
Safety Issues
In general, CDP-choline appears to be safe. The study of oral CDP-choline for
Parkinsons disease reported only a few brief, nonspecific side effects such as
nausea, dizziness, and fatigue. In a study of 2,817 elderly people who took oral
CDP-choline for up to 60 days for problems other than Parkinsons disease, side
effects were few and mild and reported in only about 5% of participants.
Two-thirds of these side effects were gastrointestinal (nausea, stomach pain,
and diarrhea), and none required stopping CDP-choline. The dose in this study
was 550 to 650 mg per day, about half the dose used for Parkinsons disease.
The safety of CDP-choline in pregnant or nursing women, young children, or
people with severe liver or kidney disease has not been established.
Other Proposed Treatments for Parkinsons Disease:
Three natural treatments have been studied for use in depression or dementia
accompanying Parkinsons disease. In addition, several other treatments have
been suggested for prevention or treatment of Parkinsons disease as a whole.
SAMe
Whether a symptom of the disease or a response to disability, depression affects
many people with Parkinsons disease, and long-term use of levodopa may
contribute to this problem. Research suggests that levodopa can deplete the
brain of a substance called S-adenosylmethionine (SAMe for short). As SAMe has
been found in a number of small studies to have antidepressant effects, it is
possible that depleting it might trigger depression.
Researchers conducted a trial to determine if taking SAMe supplements could
decrease depression in 21 individuals with Parkinsons disease who were taking
levodopa. In this double-blind study, each participant received either a
combination of oral and injected SAMe or placebo daily for 30 days, followed by
the alternate treatment for another 30 days. Although other symptoms of
Parkinsons didnt change, 72% of people taking SAMe felt that their depression
was improved after 2 weeks, while only 30% noted improvement with placebo. It is
not yet known if oral SAMe alone would have similar effects.
Although SAMe might appear to be an excellent accompaniment to levodopa, there
is another side to the issue. During treatment with levodopa, SAMe participates
in breaking it down and gets used up in the process. It is possible that taking
extra SAMe could lead to decreased effectiveness of levodopa. In the short-term
study described above, SAMe did not interfere with levodopas effects, but
longer-term use might do so.
The bottom line: If you have Parkinsons disease, its safest to use SAMe—if at
all—only under the supervision of a physician.
For more information, including dosage and safety issues, see the full SAMe
article.
5-HTP
Another natural substance, 5-HTP (5-hydroxytryptophan), is often used for
depression and has also been tried for depression in Parkinsons disease.
However, the evidence that it works is extremely preliminary.
Note: Avoid 5-HTP if you take carbidopa. Using the two substances together might
increase your chance of developing symptoms resembling those of the disease
scleroderma.
For more information, including dosage and safety issues, see the full 5-HTP
article.
Phosphatidylserine
Phosphatidylserine—PS for short—is a major component of cell membranes. Several
studies have found PS supplementation effective for improving mental function in
individuals with Alzheimers disease. One trial examined its use in 62 people,
all of whom had both Parkinsons disease and Alzheimers-type dementia. The
results appeared to indicate some benefit, but due to the incompleteness of the
report on this trial, it is difficult to draw conclusions.
Vitamin E
Because of indications that free radicals play a role in causing Parkinsons
disease, treatment with high doses of vitamin E has been tried to see if they
can slow down the progression of Parkinsons disease. However, a large study
yielded disappointing results. In this trial, 800 individuals newly diagnosed
with Parkinsons disease took 2,000 IU of tocopherol (synthetic vitamin E) or
placebo daily for an average of 14 months. Vitamin E had no effects in delaying
symptoms of the disease—nor did it reduce side effects of levodopa.
For more information, including dosage and safety issues, see the full vitamin E
article.
Vitamin C
One problem with levodopa treatment for Parkinsons disease is the so-called
"on-off effect," in which a person taking levodopa will move more freely for
some hours, followed by sudden "freezing up." Vitamin C has been tried as a
remedy for "on-off effects" in a small double-blind study,27 but the results
were so minimal that the researchers didnt feel justified in recommending it.
Other Treatments
A few other treatments for Parkinsons disease, with minimal or conflicting
evidence, includeNADH,28,29,30 glutathione, policosanol, and the amino acids
D-phenylalanine, and L-methionine. Caution is advised with the latter three, as
they might affect the function of L-dopa. (See Other Safety Issues, below.)
Treatments sometimes mentioned but essentially lacking any scientific data
include N-acetyl cysteine, beta-carotene, coenzyme Q10, the hormone pregnenolone,
and vitamin B6. Be aware of the cautions regarding vitamin B6, noted below.
Other Safety Issues
If you have Parkinsons disease, it is best to avoid taking the herb kava.
Preliminary reports suggest that kava may counter the effects of dopamine and
possibly reduce the effectiveness of medications for Parkinsons.
Other substances may also interact with Parkinsons drugs. Iron supplements can
interfere with absorption of levodopa and carbidopa, and should not be taken
within 2 hours of either medication. Amino acid supplements, such as BCAAs
(branched-chain amino acids), can temporarily decrease levodopas effectiveness,
as may methionine and phenylalanine, two amino acids studied for treatment of
Parkinsons disease.
Vitamin B6 in doses higher than 5 mg per day might also impair the effectiveness
of levodopa, and should be avoided. However, if you take levodopa/carbidopa
combinations, this restriction may not necessarily apply. Talk with your
physician about an appropriate dose of vitamin B6.
As noted above, SAMe and 5-HTP may interact with some Parkinsons drugs. In
addition, one report suggests that by amplifying the action of levodopa,
policosanol might increase side effects called "dyskinesias."