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In the News
Fish Oil May Help
Prevent Alzheimer's
The omega-3 fatty acids found in fish oil might play an important role in
preventing Alzheimer's disease, according to a research team at the
University of California, Los Angeles (UCLA). Published in the Dec. 26 issue
of the Journal of Neuroscience, the scientists demonstrated that the omega-3
fatty acid docosahexaenoic acid (DHA) increases the production of LR11, a
protein that is found at reduced levels in Alzheimer's patients. LR11 is
known to destroy the protein that forms the plaques associated with the
disease, the researchers explained.
The plaques are actually a buildup of a protein called beta amyloid, which
is thought to be toxic to brain cells. Higher levels of LR11 prevent the
manufacturing of the toxic proteins, which is why researchers believe the
low levels found in the brains of Alzheimer's patients may be a contributing
factor to the disease.
Alzheimer's is a debilitating neurodegenerative disease that causes memory
loss, dementia, personality change and ultimately death. The Alzheimer's
Association estimates that 5.1 million Americans are currently afflicted
with the disease. The association predicts that may increase to between 11
million and 16 million people by 2050.
The researchers tested the effects of DHA by adding it directly to human and
animal neurons grown in the laboratory.
"We found that even low doses of DHA increased the levels of LR11 in rat
neurons, while dietary DHA increased LR11 in brains of rats or older mice
that had been genetically altered to develop Alzheimer's disease," lead
researcher Greg Cole, associate director of UCLA's Alzheimer Disease
Research Center, said in a prepared statement.
Fatty acids such as DHA are considered essential fatty acids, because the
body cannot make them from other sources and must obtain them through diet.
Years of research have shown that DHA is the most abundant essential fatty
acid in the brain, Cole said, and that it is critical to fetal and infant
brain development. Studies have also linked low levels of DHA in the brain
to cognitive impairment and have shown that lower levels may increase
oxidative stress in the brains of Alzheimer's patients.
The research team acknowledged that their work does not identify a dosage of
DHA that people could take to prevent Alzheimer's, but they recommend eating
more fatty fish or taking a supplement. They did not recommend taking DHA to
try to slow the progression of Alzheimer's.
Flax Seed May Slow
Prostate cancer
A new study commissioned by the National Institute of Health shows real
promise for a nutritional aid in the fight against prostate cancer.
The flaxseed study was aimed at fighting prostate cancer, not treating a
side effect. The edible seed has been used for hundreds of years in cereals
and breads and is high in beneficial omega-3 fatty acids and in lignan, a
substance that can affect hormone levels and perhaps squelch their
cancer-promoting effects.
Four groups of about 40 men who were scheduled to have their prostates
removed three weeks later were assigned to get either 30 grams of powdered
flaxseed, a low-fat diet, both or neither until their surgery.
After the men's prostates were removed, researchers found that tumors had
been growing 30 to 40 percent slower in the two groups taking flaxseed,
based on how quickly cells were multiplying. Low-fat diets had no effect on
this, said Wendy Demark-Wahnefried of Duke University Medical Center, who
led the study.
"Our findings are compelling but they're preliminary," she cautioned. But
several doctors said flaxseed is nutritious and seems to have little
downside other than a sawdust-like consistency, since it must be used ground
or powdered because it has an inedible hull or coating. Scientists plans to
study flaxseed on men with prostate cancer that comes back after initial
treatment, and Canadian scientists also are testing it for breast cancer,
she said.
Vitamin D deficiency tied to higher blood pressure
Low blood concentrations of
vitamin D may be associated with higher blood pressure in whites, indicating
a risk of developing hypertension, or high blood that requires medical
treatment, researchers report. However, this relationship was not noted
among blacks.
"Though easily corrected by taking a vitamin D supplement or having
causal sunlight exposure, vitamin D insufficiency is highly prevalent in the
United States," Dr. Vin Tangpricha told Reuters Health.
Tangpricha and colleagues, all from Emory University School of Medicine
in Atlanta, looked at the association between systolic blood pressure - the
top number of the blood pressure reading representing the pressure during
contraction of the heart muscle -- and vitamin D levels among 7,699 adults
without high blood pressure. Forty-seven percent were male, 61 percent were
white, and 39 percent were black.
The study population had participated in the third National Health and
Examination Survey conducted from 1988 to 1994, which provides the most
recent nationally representative data on vitamin D concentrations among U.S.
adults, the investigators report in the American Journal of Clinical
Nutrition.
Overall, 61 percent of whites and 92 percent of blacks had vitamin D
deficiency. Most (63 percent) of the participants were 18 to 49 years old,
and 37 percent were 50 years or older when systolic blood pressure and
vitamin D measurements were obtained.
The investigators found that white participants with sufficient vitamin D
levels had a 20-percent lower rise in age-associated systolic blood pressure
compared with those with insufficient vitamin D levels. This relationship
was not statistically significant in blacks.
"This paper does not provide direct evidence that vitamin D
supplementation will lower blood pressure," Tangpricha cautions.
He and colleagues suggest that further research examine in more detail
how vitamin D status affects blood pressure in black and white populations.
Improved methods for detecting vitamin D deficiency are also necessary, they
conclude.
SOURCE: American Journal of Clinical Nutrition, January
2008.
Higher Folate Levels Linked to Reduced Risk
for Alzheimer’s Disease
ScienceDaily (Jan. 9, 2007) — Individuals who
take in higher levels of the nutrient folate through
both diet and supplements may have a reduced
risk of developing Alzheimer’s disease, according
to a report in the January issue of Archives of
Neurology, one of the JAMA/Archives journals.
By the year 2047, the prevalence of Alzheimer’s disease
is expected to quadruple. Delaying the onset of this
neurodegenerative disease would significantly reduce
the burden it causes. Researchers suspect that elevated
levels of the amino acid homocysteine in the blood, which
is linked to a higher risk for cardiovascular disease and
stroke, may also increase the risk for Alzheimer’s disease.
Folate, vitamin B12 and vitamin B6, are important in
the body’s processing of homocysteine – therefore,
deficiencies in these nutrients increase homocysteine
levels and may contribute to cardiovascular disease,
stroke and dementia.
José A. Luchsinger, M.D., Columbia University
Medical Center, New York, and colleagues examined,
interviewed and assessed the diets of 965 individuals
without dementia between 1992 and 1994 and then
followed them for an average of 6.1 years to see if they
developed Alzheimer’s disease. The participants had an
average age of 75.8 and 70.2 percent were women,
32.6 percent African-American, 45.3 percent Hispanic
and 22.1 percent white.
During the follow-up period, 192 of the participants
developed Alzheimer’s disease. When the individuals
were divided into four groups based on the total level
of folate they took in through food and supplements
and the analysis was adjusted for patient characteristics,
comorbid diseases and B12 and B6 intake, the risk of
Alzheimer’s disease was lower in the groups with higher
intake. Neither dietary folate nor supplements alone
were significantly linked to Alzheimer’s disease risk; only
the two in combination appeared to produce an effect.
Levels of the vitamins B12 and B6 were not associated
with Alzheimer’s disease risk.
Higher folate intake was modestly correlated with
lower homocysteine levels, “indirectly suggesting that a
lower homocysteine level is a potential mechanism for
the association between higher folate intake and a lower
Alzheimer’s disease risk,” the authors write.
Definitive conclusions about the role of folate in
the development of Alzheimer’s disease cannot yet be
made. The findings of this study are in contrast to those
of some other research, and other compounds (such as
hormones) perceived to reduce the risk for dementia in
observational studies did not do so in randomized trials.
Thus, the decision to increase folate intake to prevent
Alzheimer’s disease should await clinical trials.
Adapted from materials provided by JAMA and Archives
Journals, via EurekAlert!, a service of AAAS.
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