Fish Oil Supplements Found to Have No Meaningful Brain Benefits Despite Reaching the Brain

Study Overview

Fish oil supplements successfully delivered omega-3s to the brain, but a two-year study found no meaningful benefits for memory, cognition, or Alzheimer's-related brain changes. Researchers recruited 365 adults, ages 55 to 80 who rarely ate fish and who study authors considered at risk for Alzheimer's. About half (47%) carried an APOE4 gene, the strongest genetic risk factor for late-onset Alzheimer's.

The Omega-3 Delivery Question

The supplements contained 2,000 mg of docosahexaenoic acid (DHA), a key omega-3 involved in brain function. Researchers first wanted to know whether the key omega-3 nutrient, DHA, was actually reaching the brain. So, they measured DHA levels in the surrounding fluid and found an increase of about 17% after six months of treatment. However, that didn't translate into better outcomes, according to the results. Memory tests and brain scans showed no advantage for those taking fish oil supplements.

Implications for Prevention

The results challenge the idea that fish oil pills can help prevent Alzheimer's and shift attention toward overall diet and lifestyle instead. Americans spend more than $1 billion each year on fish oil supplements, largely because of claims that the omega-3 fatty acids they contain can support brain health.

Clinical Verdict

The two-year, placebo-controlled, double-blinded study of older adults with an elevated risk of developing Alzheimer's showed that high doses of omega-3s did not improve memory, cognitive function or brain cell loss in areas of the brain related to Alzheimer's. This research represents one of the largest and most rigorous investigations into fish oil's cognitive benefits to date.