Advertisement The study was conducted in mice, but senior author Greg Cole said it probably applies to humans as well.
"Our data show it works in animals," said Cole, associate director of the Alzheimer's Disease Research Center at the UCLA David Geffen School of Medicine.
"If this works in people, it's clearly going to be one of the ways we protect ourselves from Alzheimer's disease."
They fed one group food fortified with docosahexenoic acid (DHA), the omega-3 fatty acid found in several types of coldwater fish.
They fed the other group a diet low in DHA.
Diets low in DHA have been linked to impaired mental functioning, and DHA levels are lower in the blood and brains of Alzheimer's disease patients, Cole said.
After three to five months, which translates to several years in humans, the group of mice fed the DHA-rich diet had 70 percent less buildup of amyloid protein in the brain.
While the worth of omega-3 fatty acids to prevent plaque buildup in humans is yet to be proven, Cole pointed out that omega-3 fatty acids are known to have protective effects on human hearts.
The American Heart Association recommends that healthy adults eat a minimum of two servings of fish a week, especially mackerel, sardines, albacore tuna, salmon, lake trout and herring.
Praise for the study Another Alzheimer's expert praised the study.
"There clearly is less of an accumulation of amyloid in these mice given a DHA-enriched diet," he said.
Protection against synaptic damage In another study by Cole's group, published last year in the journal Neuron, the researchers showed that DHA protected against damage to the "synaptic" areas where brain cells communicate and enabled mice to perform better on memory tests.