Alzheimer's disease is the leading
cause of dementia in people over the age of 65, affecting over 4 million North
Americans. The disease is characterized by abnormal deposits of a protein called
beta-amyloid (plaque) in the brain as well as by twisted fibers caused by
changes in a protein called "tau" (tangles). Before arriving at a diagnosis,
tests are needed to rule out a stroke, a brain tumor, and other possible causes
Blood tests can uncover genetic markers for the disease. The cause of
Alzheimer's disease remains unknown, but researchers theorize that chromosomal
and genetic factors are responsible for some cases. the increased incidence of
Alzheimer's among those with Down's syndrome, which is caused by a chromosomal
abnormality, seems to support this theory. Researchers have discovered a genetic
marker, apolipoprotein E, which can be detected by blood tests, that identifies
those likely to develop the disease. About 40 percent of sufferers have the gene
that produces this protein.
In addition, hormonal factors are under study. Women are afflicted more often
than men; studies suggest that estrogen replacement may be protective. A study
published in 2003 in the Journal of the American Medical Association,
however, has thrown cold water on this hypothesis. Women over the age of 65 who
were taking combined estrogen-progestin therapy had a higher incidence of
Alzheimer's disease than those not taking hormones. Thyroid disorders are also
linked to the disease, while the long-term use of nonsteroidal anti-inflammatory
drugs (NSAIDs) has been linked with a reduced Alzheimer's risk. These drugs may
reduce inflammation in the brain linked with the disease. There is insufficient
evidence for physicians to recommend taking anti-inflammatory drugs to ward off
Danger : Aluminum ?
There have been other intriguing
leads, but researchers have been unable to pinpoint any specific dietary factors
that increase the risk of or help to prevent Alzheimer's disease. Some research
has implicated aluminum, which has been found in the abnormal tangles of brain
cells in some Alzheimer's patients. However, extensive studies have failed to
prove that aluminum actually causes the disease, and it now seems more likely
that aluminum is found in Alzheimer's brains because the diseased brain retains
Avoid taking antacids containing
aluminum. Although most researchers discount the aluminum factor, some argue
that while the metal may not cause the disease, its increased concentration in
the Alzheimer's brain worsens the condition. They suggest that patients avoid
taking antacids with large amounts of aluminum or using cookware that allows the
metal to leach into food. Concern has also been raised about the aluminum
content of drinking water in areas where aluminum compounds are used as
flocculating agents in city water treatment.
Diet and Alzheimer's
Researchers are studying the role of
the B-vitamin folate in lowering risk of Alzheimer's. This vitamin helps
regulate blood levels of homocysteine, an amino acid, high levels of which may
play a part in the development of the disease. Studies have shown that people
with Alzheimer's have high homocysteine levels and there is evidence that high
concentrations of homocysteine in healthy adults may lead to Alzheimer's. In
addition to folate, vitamins B6 and B12 help regulate homecysteine levels.
People with high blood cholesterol and high blood pressure are also at increased
risk and taking cholesterol-lowering drugs, particularly the "stains," has been
shown to reduce the risk. Basically, it appears that what is good for the heart
is good for the brain.
The brain is rich in DHA (docosahexaenoic
acid), an omega-3 fatty acid that is plentiful in fatty fish such as salmon,
mackerel, halibut, herring, and sardines. Low levels of this fat have been
associated with age-related dementia, including Alzheimer's disease.
Antioxidants may be preventives.
They mop up free radicals and have been touted as possible preventives for
Alzheimer's since the body's ability to neutralize these rogue substances
declines with age. The most recent studies, however, may end the hype. In a
large trial published in 2003 in the Archives of Neurology, researchers
at Columbia University found that people who had high intakes of vitamins C, E,
and beta carotene did not have a reduced risk of Alzheimer's disease. Trials
with gingko biloba, another antioxidant, have also been less than encouraging.
People with Alzheimer's disease have
abnormally low levels of choline acetyltransferase, an enzyme necessary to make
acetylcholine, a brain chemical believed to be instrumental in learning and
memory. Also, the brain cells most affected by Alzheimer's are those that
normally respond to acetylcholine. In addition, tacrine (Cognex), a drug that
appears to improve the memory of some Alzheimer's patients, increases levels of
acetylcholine. Some nutrition researchers theorize that supplements or foods
high in lecithin or choline (the major component of acetylcholine) can also slow
the progression of Alzheimer's by raising acetylcholine production. So far,
studies have failed to document its value, but some nutritionists feel that
foods high in lecithin and choline may help forestall symptoms and will
certainly do no harm; these include egg yolks, organ meats, soy products,
peanuts, wheat germ, and whole grains.
Monitor nutrition carefully.
As the disease progresses, its victims may forget to eat or eat only sweets or
other favorite foods. patients should be persuaded to eat nutritionally balanced
meals. they may need to be spoon-fed if they have difficulty feeding themselves.
A multivitamin may also be advisable; high-dose supplements should not be
administered unless specifically recommended by a physician.
Even in small amounts, alcohol
destroys brain cells, a loss that a healthy person can tolerate but one that can
accelerate the progression of Alzheimer's disease. Alcohol interacts with
antidepressants, sedatives, and other medications prescribed for Alzheimer's
patients. It's a good idea to avoid all alcohol.
Evidence is accumulating for the "use
it or lose it" theory of reducing Alzheimer's risk. People who exercise their
brains with education, puzzles, games, and museum visits seem to be less
sensitive to brain damage.