UCLA neuroscientists have shown for the first time that a diet high in the omega-3 fatty acid DHA helps protect the brain against the memory loss and cell damage caused by Alzheimer's disease. The new research suggests that a DHA-rich diet may lower one's risk of Alzheimer's disease and help slow progression of the disorder in its later stages. The journal Neuron reported the findings on Sept. 2.
"This is the first proof that our diets affect how our brain cells communicate with each other under the duress of Alzheimer's disease," said Greg Cole, senior author and a professor of neurology at the David Geffen School of Medicine at UCLA. "We saw that a diet rich in DHA, or docosahexaenoic acid, dramatically reduces the impact of the Alzheimer's gene.
"Consuming more DHA is something the average person can easily control," added Cole, associate director of the UCLA Alzheimer's Disease Research Center. "Anyone can buy DHA in its purified form, fish-oil capsules, high-fat fish or DHA-supplemented eggs."
Cole and his colleagues focused on Alzheimer's damage to synapses — 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 UCLA researchers created a mouse model to test environmental risk factors for the disorder. When the mice developed the lesions, but showed minimal memory loss or synaptic brain damage, however, the scientists took a closer look at the animals' diet.
"We discovered that the mice lived on a nutritious diet of soy and fish — two ingredients chock-full of omega-3 fatty acids," said Sally Frautschy, co-author and an associate professor of neurology at the school.
"Because earlier studies suggest that omega-3 fatty acids may prevent Alzheimer's disease, we realized that the mice's diet could be countering the very thing we were trying to accomplish — showing the progression of the Alzheimer's-related brain damage," she said.
The UCLA team swapped safflower oil for the soy and fish to create an unhealthful diet depleted of omega-3 fatty acids. They divided the animals into two sets of older mice, which already showed brain lesions but displayed no major loss of brain-cell activity. The researchers placed both groups on the new diet, but fed the second group DHA supplements from algae.
After five months, the researchers compared each set of mice to a control group that consumed the same diet but did not carry the Alzheimer's genes. The results surprised them.
"We found high amounts of synaptic damage in the brains of the Alzheimer's-diseased mice that ate the DHA-depleted diet," Frautschy said. "These changes closely resembled those we see in the brains of people with Alzheimer's disease."
Although the mice on the DHA-supplemented diet also carried the Alzheimer's genes, they still performed much better in memory testing than the mice in the first group.
"After adjusting for all possible variables, DHA was the only factor remaining that protected the mice against the synaptic damage and memory loss that should have resulted from their Alzheimer's genes," Cole said. "We concluded that the DHA-enriched diet was holding their genetic disease at bay."
The present results provide, for the first time, evidence that the combination of genetic (mutant human APP) and environmental risk factors (dietary essential fatty acids) for AD can act synergistically to quantitatively reduce synaptic proteins, specifically, dendritic scaffold proteins, that are critical for cognition as evidenced by memory deficits observed in the Morris water maze paradigm," wrote the researchers.
"The results show a dramatic impact of diet on the expression of the AD-related postsynaptic marker phenotype and provide new insight into how essential fatty acid intake may modulate the expression of neurodegenerative diseases, including AD," they wrote.
The researchers also wrote that their findings "suggest that patients bearing a genetic risk of AD may be more vulnerable to a lack of essential fatty acids," which tend to be reduced in the brain both in normal aging and AD. They concluded that their findings "support the idea that increased DHA intake should be considered as a potential neuroprotective strategy for AD."
Omega 3 fatty acids are not the only nutrients that have been found to slow Alzheimer's Disease progression in mice genetically engineered to develop the disease. Dr. James Joseph, associate professor of nutrition and chief of the Neuroscience Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts Univesity has found that blueberries help maintain normal cognitive function in mice genetically engineered to develop Alzheimer's.
Joseph continues to research the benefits of blueberries, which, among other things, have been found to improve memory. Collaborating with researchers at the University of Florida, Joseph is working worked with double-transgenic mice that have been genetically programmed to have Alzheimer's disease. When fed a diet of blueberries for 11 months, the mice's Y-maze performance was normal, and he recorded in them a higher level of expression of enzymes associated with signal transduction than in the control group.
"Either directly or working as an antioxidant, the diet appears to have an effect on synaptic plasticityŃthe signal transduction or communication between neurons," says Joseph.
The challenge, then, is to find a way to make a blueberry fish dish. I personally find that pineapple works mixed in as a flavoring with salmon. Haven't tried blueberries and salmon yet.
|Share |||Randall Parker, 2004 September 14 01:35 PM Brain Alzheimers Disease|