USC TRIAL FINDS NO COGNITIVE BENEFIT FROM FISH OIL SUPPLEMENTS

Researchers at Keck Medicine of USC said a two-year trial found that high-dose fish oil supplements did not improve memory or thinking skills in adults at increased risk of Alzheimer's disease. The study enrolled 365 people who rarely ate fish. Participants who took omega-3 supplements daily performed no better on cognitive tests than those given a placebo, according to the researchers. Brain scans also showed no protection against shrinkage in a region important for memory.

The researchers reported that the supplements raised levels of a key fatty acid in the fluid surrounding the brain and spinal cord. The findings appeared in the journal eBioMedicine. Nearly half the participants, 47%, carried the APOE4 gene variant, which the researchers described as the strongest known genetic risk factor for late-onset Alzheimer's disease. Omega-3 fatty acids occur in fatty fish including salmon, sardines and mackerel.

Fish oil is among the most widely used dietary supplements in the United States, according to the researchers. They said Americans spend more than $1 billion a year on products containing omega-3 fatty acids. Hussein Naji Yassine, director of the USC Centre for Personalized Brain Health and the study's lead investigator, said the nutrients help form connections between brain cells. “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 said.