Findings published in the journal Alzheimer's & Dementia indicated that fish oil supplements may conserve brain volume and cognition across the spectrum of normal aging and neurodegeneration.
“This study is the first to report an association between fish oil supplements use and brain structural changes in all three cognitive diagnostic groups; these findings may suggest a potential role for fish oil supplements by reducing neurodegeneration over time,” wrote the researchers. “The neuroprotective activities of n-3 PUFAs may be largely mediated through vascular effects; however, other mechanisms have been proposed, including the activities of neuroprotectin D1 (NPD1), a potent lipid mediator synthesized from DHA during periods of oxidative stress.”
The study analyzed data from 229 cognitively normal individuals, 397 patients with mild cognitive impairment, and 193 patients with Alzheimer's disease. While all the groups experienced benefits, the response was not observed for people with the genetic risk factor for Alzheimer's disease (AD) known as ApoE4. Previous data indicates that carriers of the APOE4 allelic variant (about 25% of whites) are at a several-fold increased risk of Alzheimer’s disease.
However, the researchers could not conclude a causal effect of fish oil supplements on cognition and brain atrophy. Despite this, the results “highlight the need for future research on the effects of long-term fish oil supplement use on cognitive aging and dementia prevention in middle-aged and older adults”, they said.