A high intake of the omega-3 fatty acid DHA can help protect the
brain from memory loss and cell damage caused by Alzheimer's disease.
For the first time, neuroscientists have research that suggests
that a diet rich in DHA, or docosahexaenoic acid, may help slow
the progression of Alzheimer's and even lower the risk of getting
the disorder.
Researchers said the study proved that DHA "dramatically reduces
the impact of the Alzheimer's gene."
They also said the average American easily can add more omega-3
DHA to his or her diet. Alzheimer's experts suggest several DHA
product options, including fish-oil capsules, high-fat fish or DHA-supplemented
eggs. The human brain absorbs DHA rapidly, making a constant supply
critical for proper cognitive function, eye development and mental
tasks. DHA helps keep the brain membrane fluid, move proteins and
helps to convert signals from other parts of the body into action.
During the study, researchers focused on Alzheimer's damage to
synapses, which are the chemical connections between brain cells
that enable memory and learning.
By using mice bred with genetic mutations that cause the brain
lesions linked to advanced Alzheimer's disease, the scientists created
a mouse model to test environmental risk factors for the disorder.
The mice developed lesions, but they showed minimal memory loss
or synaptic brain damage. That's when the researchers took a closer
look at what the mice ate.
They discovered that the mice primarily consumed soy and fish,
two ingredients rich in omega-3 fatty acids.
Because previous research had suggested that omega-3 might prevent
Alzheimer's disease, the scientists thought the animals' diet could
be fighting the progression of brain damage.
To test this theory, the mice were divided into two groups of older
mice, which already showed brain lesions but showed no major loss
of brain-cell activity. Researchers fed both groups of mice safflower
oil, which is not high in omega-3 fatty acids, instead of fish and
soy. The second group also consumed DHA supplements from algae.
After five months, scientists compared each group of mice to a
control group that consumed the same diet but did not carry the
Alzheimer's genes. The results surprised them.
According to researchers, they found a great deal of synaptic damage
in the brains of the Alzheimer's mice that ate a low-DHA diet. The
results were very similar to the changes seen in human Alzheimer's
patients. Those mice with the disease that did consume large amounts
of DHA performed better during memory tests than the first group.
Scientists concluded that DHA was the only possible factor that
could have protected the mice from the synaptic damage and memory
loss that should have occurred from the disease-carrying genes.
In other words, it kept Alzheimer's at bay.
Head researchers on the team hope to use this information in a
new study that will track DHA-related biomarkers in urine and spinal
fluid of Alzheimer's patients. Detecting the biomarkers earlier
would mean sooner treatment.
Inexpensive sources of DHA include coldwater fish, such as salmon,
halibut, mackerel, sardines and herring. These fish consume algae,
which is high in DHA. However, these fish are more prone to absorbing
mercury, dioxin, PCP and other metals. A less risky, but more expensive,
option is to consume fish oil or purified DHA supplements made from
algae. Other options include DHA-rich eggs laid by chickens that
eat DHA-supplemented feed.
EurekAlert
September 1, 2004
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