Nutrition & DietLarge Trial Finds Fish Oil Supplements Offer No Brain Health or Memory Benefits
A major two-year clinical trial from Keck Medicine of USC tested whether high-dose omega-3 fish oil supplements could protect brain health in older adults at elevated Alzheimer's risk. The study enrolled 365 adults aged 55–80 who rarely ate fish, nearly half carrying the APOE4 gene. Participants took 2,000 mg of DHA daily or a placebo. DHA successfully reached the brain, confirmed by a 17% rise in cerebrospinal fluid levels. Despite this, supplement takers showed no improvement in memory or cognition compared to placebo, and brain scans revealed no slowdown in hippocampal shrinkage. Researchers conclude fish oil pills are unlikely to prevent Alzheimer's, redirecting focus toward whole diet and lifestyle approaches.
