Antioxidant vitamin supplements, particularly vitamins
E and C, may protect the aging brain against damage
associated with the pathological changes of Alzheimer's
disease, according to a study conducted by the Johns
Hopkins Bloomberg School
of Public Health and other institutions. The
researchers believe antioxidant vitamin supplements may be
an ideal prevention strategy for our aging population as
they are relatively nontoxic and are thought to have
wide-ranging health benefits. The study is published in the
January issue of the journal Archives of
Neurology.
Peter P. Zandi, lead author of the study and an
assistant professor in the school's
Department of Mental
Health, said, "These results are extremely exciting.
Our study suggests that the regular use of vitamin E in
nutritional supplement doses, especially in combination
with vitamin C, may reduce the risk of developing
Alzheimer's disease."
The researchers examined data from the Cache County
Study, which is a large, population-based investigation of
the prevalence and incidence of Alzheimer's disease and
other dementias. Residents who were 65 or older were
assessed from 1996 to 1997 and again from 1998 to 2000.
Study participants were asked at their first contact about
vitamin usage. The researchers then compared the subsequent
risk of developing Alzheimer's disease over the study
interval among supplement users versus nonusers to come to
their conclusions.
Approximately 17 percent of the study participants
reported taking vitamin E or C supplements. These
individuals were significantly more likely to be female,
younger and better educated and reported better general
health when compared to nonsupplement users. In addition to
those who took vitamin supplements, another 20 percent of
study participants used multivitamins but without a high
dosage of vitamin E or C.
The researchers found a trend toward reduced
Alzheimer's disease with a combination of vitamin E and C
supplements, even after controlling for age, sex, education
and general health. However, there was no notable reduction
in the risk of Alzheimer's disease with vitamin E or
vitamin C alone or with multivitamins. Multivitamins
typically contain the recommended daily allowance of
vitamin E (22 IU or 15 mg) and vitamin C (75-90 mg), while
individual supplements contain doses up to 1,000 IU of
vitamin E and 500-1,000 mg or more of vitamin C.
The researchers explained that the use of vitamins E
and C may offer protection against Alzheimer's disease when
taken together in the higher doses available in individual
supplements. In addition, there may be some protective
effect with vitamin E when it is combined with the lower
doses of vitamin C found in multivitamins.
Zandi said, "Further study with randomized prevention
trials is needed before drawing firm conclusions about the
protective effects of these antioxidants. Such trials
should consider testing a regimen of vitamin E and C in
combination. If effective, the use of these antioxidant
vitamins may offer an attractive strategy for the
prevention of Alzheimer's disease."
The study was funded by grants from the National
Institutes of Health and National Institute of Mental
Health. The Bryan Alzheimer's Disease Center at Duke
University completed the APOE genotyping.
Co-authors of the study from Johns Hopkins were James
C. Anthony, Ara S. Khachaturian and John C.S. Breitner.
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