Alzheimer's Disease, the links between diet and
dementia
Researchers are discovering powerful links between diet and dementia. While
there is no special nutritional formula recommended for Alzheimer’s
disease, certain nutrients may help to ward off the degenerative brain disorder.
Damage caused by free radicals is thought to play a major role in the development
of Alzheimer's Disease. Many researchers have investigated whether antioxidants
(agents known to scavenge free radicals) may ease the symptoms of dementia,
increase the life span of those with AD, and help prevent the disease. Two
antioxidants in particular, vitamins E and C, have shown promise in both
the prevention and treatment of the disease. Research on other supplements
is less convincing.
Vitamin E dissolves in fat, readily enters the brain, and helps slow down
the cell damage that occurs naturally with age. In a well-designed study
involving 341 people with AD who were followed for 2 years, researchers
found that people who took vitamin E supplements had improvement in their
symptoms and increased survival rates compared to those who took placebo.
Two large trials suggest that vitamins E and C may prevent the onset of
AD, improve cognitive skills in healthy individuals, and decrease the symptoms
of dementia. In one of the studies, more than 600 healthy individuals were
followed for an average of 4 years. A total of 91 people developed AD, but
none of the participants who took vitamin E or C supplements developed the
disease.
S-adenosylmethionine (SAMe)
SAMe is a naturally occurring
compound that increases the body's levels of serotonin, melatonin, and dopamine.
Clinical studies suggest that people with AD and depression have depleted
levels of SAMe in their brain tissue. While it has been reported that some
people with AD have improved cognitive function from SAMe supplementation,
further studies are needed to determine how effective this supplement may
be for individuals with the disease.
Preliminary studies suggest that levels of vitamin A and its precursor,
beta-carotene, may be significantly lower in people with AD compared to
healthy individuals, but the effects of supplementation have not been studied.
Folate is a substance critical to the health of the nervous system and to
a process that clears homocysteine from the blood. Homocysteine is a body
chemical that contributes to chronic illness such as heart disease, depression,
and AD. Elevated levels of homocysteine and decreased levels of both folate
and vitamin B12 have been found in people with AD.
In addition to being structurally similar to the brain chemical acetylcholine,
acetyl-L-carnitine is a scavenger of free radicals and is involved in the
growth of brain cells. Several studies have examined the role of acetyl-L-carnitine
in treating AD, but results have been conflicting. For example, one trial
suggests that this supplement may help prevent the progression of AD in
the early stages of the disease, but it may worsen symptoms in later stages
of the disease. Use of this supplement for AD should be avoided, therefore,
until more information is available.
Red Wine and Grape Juice
Resveratrol, a flavonoid
or plant substance found in red wine and grape juice, is an antioxidant
that may benefit people with AD. Because the alcohol in red wine may contribute
to falls, interactions with medications, and sleepiness, it is not recommended
for those with the condition.
Ginkgo (Ginkgo biloba)
Ginkgo Biloba is widely
used in Europe for treating dementia. It improves blood flow in the brain
and contains flavonoids (plant substances) that act as antioxidants. Although
many of the clinical trials have been scientifically flawed, the evidence
that ginkgo may improve thinking, learning, and memory in people with AD
has been highly promising.
Clinical studies indicate that gingko provides the following benefits for
people with AD:
• Improvements in thinking, learning, and memory
• Improvements in daily living
• Improvements in social behavior
• Delayed onset of symptoms
• Reduced symptoms of depression
Recommended dosages for ginkgo range between 120 to 240 mg per day. Reported
side effects have been minor, but ginkgo should not be taken with blood-thinning
medications (such as warfarin), vitamin E, or a class of antidepressants
called monoamine oxidase inhibitors (MAOIs).
Preliminary studies indicate that the following herbs may also slow the
progression of AD and improve memory and behavior:
• Asian ginseng (Panax ginseng) and American ginseng (Panax
quinquefolium)
• Nicotine (Nicotiana tobaccum)
• Huperzine (Huperzia serrata)
• Snowdrop (Galanthus nivalus)
• Physostigmine (Physostigma venenosa)
Although the following herbs have not been investigated in clinical studies,
they may be recommend for people with AD:
