• Posted June 19, 2026

Fish Oil Supplements May Be A Bust For Alzheimer's Prevention

Millions of Americans take fish oil supplements hoping to keep their brains sharp as they age.

But evidence just published in the journal EBioMedicine suggests those capsules may not deliver the cognitive boost many expect.

"We all wish there was a silver bullet for preventing Alzheimer's, but our findings showed that fish oil supplements do not appear to protect brain health," said lead author Dr. Hussein Naji Yassine, director of the USC Center for Personalized Brain Health. 

"While omega-3s play an important role in forming brain cell connections needed for cognition, our results do not support fish oil supplements as a preventive measure against Alzheimer’s," he added in a news release.

A two-year clinical trial followed 365 adults between the ages of 55 and 80 who were at increased risk for Alzheimer's disease. Participants received either a daily high-dose omega-3 supplement or a placebo.

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.

But 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.

Participants who received DHA saw no improvement in memory or cognitive function, and the supplements did not slow shrinkage in brain regions linked to Alzheimer's disease, according to the results.

Researchers say the findings suggest fish oil supplements alone are unlikely to prevent the most common form of dementia.

"Staying healthy throughout life remains the most powerful tool we have for reducing Alzheimer’s risk, including regular exercise, quality sleep and a balanced diet," Yassine said.

More information

The Alzheimer's Association has more on maintaining a healthy brain.

SOURCE: HealthDay TV, June 19, 2026