X-Message-Number: 28469
Date: Tue, 19 Sep 2006 21:35:09 -0700 (PDT)
From: Doug Skrecky <>
Subject: fruit juices seem to protect against Alzheimer's

Juices May Reduce Alzheimer's Disease Risk
In a large epidemiological study, researchers found that people who drank
three or more servings of fruit and vegetable juices per week had a 76
percent lower risk of developing Alzheimer's disease than those who drank
juice less than once per week.

The study by Qi Dai, M.D., Ph.D., assistant professor of Medicine, and
colleagues appears in the September issue of The American Journal of
Medicine.

The researchers followed a subset of subjects from a large cross-cultural
study of dementia, called the Ni-Hon-Sea Project, which investigated
Alzheimer's disease and vascular dementia in older Japanese populations
living in Japan, Hawaii and Seattle, Wash.

For the current study, called the Kame Project, the researchers
identified 1,836 dementia-free subjects in the Seattle population and
collected information on their dietary consumption of fruit and vegetable
juices. They then assessed cognitive function every two years for up to
10 years.

After controlling for possible confounding factors like smoking,
education, physical activity and fat intake, the researchers found that
those who reported drinking juices three or more times per week were 76
percent less likely to develop signs of Alzheimer's disease than those
who drank less than one serving per week.

The benefit appeared particularly enhanced in subjects who carry the
apolipoprotein E  -4 allele, a genetic marker linked to late-onset
Alzheimer's disease -- the most common form of the disease, which
typically occurs after the age of 65.

The researchers chose to study this group because of the low incidence
rate of Alzheimer's disease in the Japanese population. However, the
incidence of Alzheimer's in Japanese people living in the United States
is higher, approaching the incidence rates in Americans. This pointed to
environmental factors like diet and lifestyle as important contributors to
disease risk.

Originally, researchers suspected that high intakes of antioxidant
vitamins (vitamins C, E and -carotene) might provide some protection
against Alzheimer's disease, but recent clinical studies have not
supported this hypothesis.

"We thought that the underlying component may not be vitamins, that there
was maybe something else," Dai said.

Dai began to suspect that another class of antioxidant chemicals, known
as polyphenols, could play a role. Polyphenols are non-vitamin
antioxidants common in the diet and particularly abundant in teas, juices
and wines. Most polyphenols exist primarily in the skins and peels of
fruits and vegetables. Recent studies have shown that polyphenols (like
resveratrol in wine) extend maximum lifespan by 59 percent and delay
age-dependent decay of cognitive performance in animal models.

[Doug's note: This 59 percent figure was from a lifespan study of a short
lived fish species.]

"Also, animal studies and cell culture studies confirmed that some
polyphenols from juices showed a stronger neuroprotective effect than
antioxidant vitamins. So we are now looking at polyphenols," Dai said.

The next step, said Dai, is to test the subjects' blood samples to see if
elevated levels of polyphenols are related to the reduced risk of
cognitive decline and Alzheimer's disease. This would provide further
evidence of the role of juice polyphenols in Alzheimer's disease risk. It
also may point to the types of juice that would be most beneficial.

We don't know if it is a specific type of juice (that reduces risk). That
information was not collected in the current study," said Dai. "But we
can use plasma to narrow down the kinds of juices."

However promising the study results appear, Dai cautioned, it's important
that the general public not jump the gun regarding the value of juice as
a preventive measure for Alzheimer's disease.

"A few years ago, hormone replacement therapy, NSAIDs (nonsteroidal
anti-inflammatory drugs) and antioxidant vitamins showed promise (in
preventing or slowing Alzheimer's disease), but recent clinical trials
indicate that they do not," Dai said. "More study, I think, is needed."

(abstract below)

The American Journal of Medicine
Volume 119, Issue 9 , September 2006, Pages 751-759
Fruit and Vegetable Juices and Alzheimer's Disease: The Kame Project
Abstract
Background
Growing evidence suggests that oxidative damage caused by the beta-amyloid
peptide in the pathogenesis of Alzheimer's disease may be hydrogen
peroxide mediated. Many polyphenols, the most abundant dietary
antioxidants, possess stronger neuroprotection against hydrogen peroxide
than antioxidant vitamins.

Methods
We tested whether consumption of fruit and vegetable juices, containing a
high concentration of polyphenols, decreases the risk of incident
probable Alzheimer's disease in the Kame Project cohort, a
population-based prospective study of 1836 Japanese Americans in King
County, Washington, who were dementia-free at baseline (1992-1994) and
were followed through 2001.

Results
After adjustment for potential confounders, the hazard ratio for probable
Alzheimer's disease was 0.24 (95% confidence interval [CI],
0.09-0.61) comparing subjects who drank juices at least 3 times per week
with those who drank less often than once per week with a hazard ratio of
0.84 (95% CI, 0.31-2.29) for those drinking juices 1 to 2 times per week
(P for trend < .01). This inverse association tended to be more
pronounced among those with an apolipoprotein E-4 allele and those who
were not physically active. Conversely, no association was observed for
dietary intake of vitamins E, C, or beta-carotene or tea consumption.

Conclusions
Fruit and vegetable juices may play an important role in delaying the
onset of Alzheimer's disease, particularly among those who are at high
risk for the disease. These results may lead to a new avenue of inquiry
in the prevention of Alzheimer's disease.

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