A recent study challenges the widely held belief that omega-3 supplements can enhance brain function and safeguard brain health. Researchers from Keck Medicine at the University of Southern California conducted a two-year trial involving older adults at risk of Alzheimer’s disease. Despite evidence that omega-3s do reach the brain, the study found that high doses of these supplements did not enhance memory, cognitive abilities, or prevent brain cell loss in Alzheimer’s-related regions.

Lead investigator Dr. Hussein Naji Yassine stated that while omega-3s are crucial for forming brain cell connections essential for cognition, the study results do not endorse fish oil supplements as a preventive measure against Alzheimer’s. The trial involved 365 adults aged 55-80 with a low fish intake, a natural source of omega-3 fatty acids, and at an elevated Alzheimer’s risk. Nearly half of the participants carried the APOE4 gene, a significant genetic risk factor for late-onset Alzheimer’s.

Participants were randomly assigned either daily fish oil supplements or a placebo containing 2,000 mg of docosahexaenoic acid (DHA), a brain function-linked omega-3 fatty acid. The study confirmed that DHA from the supplements reached the brain, showing a 17% increase in DHA levels in cerebrospinal fluid after six months. However, cognitive tests and brain scans after two years revealed no significant differences between those taking DHA and those on a placebo.

The researchers are now exploring why omega-3s can reach the brain without producing measurable benefits. They suggest that a Mediterranean-style diet rich in omega-3s may be more effective in reducing Alzheimer’s risk. Dr. Yassine highlighted the importance of lifestyle factors, such as exercise, quality sleep, and a balanced diet, as the most effective means to support brain health.