As we age, our brains experience moderate shrinkage—but excessive brain atrophy can be a sign of Alzheimer’s disease. A new study published in the journal of Neurology suggests that individuals with higher levels of the long-chain omega-3 fatty acids EPA and DHA (both exclusively found in fish, and fish and algae-derived supplements) maintain their brain volume better than those with lower omega-3 levels.
The research team assessed the levels of long-chain omega-3 EPA and DHA in more than 1,000 postmenopausal women and determined brain volumes with MRI scans. Eight years later, they conducted brain scans on the same group of women, who had reached an average age of 78. The results: women who had greater levels of these omega-3s also demonstrated larger total brain volume.
Women with fatty acid levels twice as high as their peers (7.5 percent vs. 3.4 percent) had a total brain volume 0.7 percent bigger. The volume of their hippocampi—a region of the brain that shows signs of shrinkage in Alzheimer’s patients even before symptoms manifest—was 2.7 percent larger. A study from 2012 evaluating a different group of people similarly reported that individuals with low DHA blood levels had a greater risk of smaller brain volumes and other signs of accelerated brain aging.
Individuals can raise their EPA and DHA levels with changes in diet and supplements. The long-chain omega-3s' EPA and DHA can be found in fish and fish oil supplements, as well as some vegetarian supplements derived from algae. These fatty acids have previously been shown to traverse the blood-brain barrier in patients with Alzheimer’s. Although short-chain omega-3 fatty acids like ALA can be found in spinach, walnuts and flax, these sources are unlikely to raise your blood levels of the long-chain EPA and DHA.
For more detail on the strengths and limitations of the evidence that long-chain omega-3 fatty acids safely protect the brain, ingested through diet or supplements, see our scientific report on the subject.
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