Two-year trial finds high-dose fish oil does not boost memory or curb brain shrinkage
A two-year USC study showed that daily fish oil supplements raised DHA levels in the brain but did not improve cognition or prevent hippocampal atrophy in older adults at risk for Alzheimer’s.
In a double-blind, placebo-controlled trial, 365 older adults with elevated Alzheimer’s risk were randomly assigned to receive either a high-dose fish oil supplement or an inactive placebo for two years. Participants, many carrying the APOE4 gene, showed a 17% increase in DHA concentrations in cerebrospinal fluid, indicating successful transport of the fatty acid to the brain. Despite this, follow-up assessments revealed no advantage in memory, thinking skills, or preservation of hippocampal size compared with the control group.
Lead investigator Hussein Naji Yassine noted that while omega-3s are essential for neuronal connections, the study does not support supplements as a preventive strategy for Alzheimer’s. The team plans to explore how dietary patterns, health status, and genetics influence the brain’s use of omega-3s and to develop agents that might enhance nutrient uptake. The findings underscore the importance of broader lifestyle measures—exercise, sleep, and a nutritious diet—over reliance on single-nutrient pills.
Why it matters
The study challenges the belief that fish oil pills alone can protect aging brains, guiding consumers and clinicians toward more holistic prevention strategies.
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