|
 upplementing diets with antioxidant vitamins C and
E may boost mental ability in later life and could protect against
vascular and some other forms of dementia, according to a study
published in the March 28 issue of Neurology, the American
Academy of Neurology's scientific journal.
 "We
believe antioxidants like vitamin E and C may protect against
vascular dementia by limiting the amount of brain damage that
persists after a stroke," said study author Kamal Masaki,
MD, of the University of Hawaii in Honolulu. "The supplements
may also play a role in providing protection against brain cell
and membrane injury involved in many aging-related diseases,
thus resulting in significantly higher scores on mental performance
tests in later life."
The study
investigated 3,385 Japanese-American men, aged 71-93, participating
in the Honolulu Heart Program, a prospective study of heart disease
and stroke initiated in 1965. The men were interviewed or surveyed
in 1982 and 1988, and were assessed for dementia and mental abilities
during exams in 1991 to 1993. Of the participants, 47 were diagnosed
with Alzheimer's disease, 35 with vascular dementia, 50 with
other or mixed types of dementia, 254 had low cognitive test
scores without diagnosed dementia, and 2,999 men showed no cognitive
difficulties.
Participants
taking both vitamin E and C supplements regularly (at least once
a week) in 1988, were 88 percent less likely to have vascular
dementia four years later and 69 percent less likely to have
forms of dementia other than vascular or Alzheimer's related
dementia or mixed forms of dementia. There was no significant
reduction in the occurrence of Alzheimer's disease four years
later.
Participants
without dementia were evaluated for mental performance and function.
Those who reported taking vitamin E and C supplements in 1988
had an approximately 20 percent greater chance of having better
cognitive function during the 1991-93 examination than those
who did not. However, men taking the supplements in both 1982
and 1988 had an approximately 75 percent greater chance of better
mental performance. This suggests that long-term use could significantly
improve cognitive function in late life.
"We originally
thought that the beneficial impact antioxidant vitamin supplements
had against vascular dementia was the prevention of stroke,"
commented Masaki. "However, to our surprise we found there
was not a significant association between vitamin supplement
use and clinically recognized stroke."
Previous reports
have shown that antioxidants may slow the progression of Alzheimer's
disease and the researchers were also surprised when they did
not find a protective effect against Alzheimer's.
"It is
critically important for patients to practice preventive efforts
shown to lower stroke risk and to have broad ranging beneficial
effects," said Masaki. "More effective strategies for
prevention also must be found. Therefore, a prevention trial
of both vitamin E and C to further examine the potential protective
effects on both vascular dementia and Alzheimer's disease is
needed."
Vascular dementia
is the second most common cause of dementia in the United States
(following Alzheimer's disease) and the most common cause of
dementia in Japan. Those with vascular dementia face the physical
impairment related to stroke, such as paralysis, and speech,
language and visual disturbances, in addition to mental impairment.
|
