Omega-3 supplements linked to faster cognitive decline in high-risk patients

The Army Medical University in China conducted research which demonstrates that omega-3 supplements do not protect the brain health of elderly individuals because the study found that participants with genetic Alzheimer's risk who used the supplements experienced faster cognitive decline than those who did not use the supplements.

The researchers studied health information from more than 800 participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI), which included approximately 50 per cent of the group carrying the APOE ε4 gene, which has been identified as a dementia risk factor.

In those using the omega-3 supplements, there was greater cognitive decline on the Mini-Mental State Examination scale, which tests memory, attention, and language. There were faster increases in cognitive decline scores, even without changes to plaques, tangles, or grey matter.

The decline correlated instead with changes to neuronal synaptic function the connections between brain cells. "Our results suggest that omega-3 supplementation may, in some contexts, adversely affect synaptic integrity, ultimately counteracting its short-term benefits," the authors explained.

The results do not confirm that the consumption of omega-3 causes cognitive impairment, but they show that there is an ideal dosage for obtaining maximum benefits. In a systematic review conducted in 2025, it was concluded that low doses of omega-3 supplements enhance cognitive function, whereas doses higher than 1,500 milligrams per day have a detrimental effect on the brain.

"Such findings contradict the widespread notion about omega-3 benefits and require the consideration of a more cautious approach to using such products," the scientists noted. The study authors noted that their research is purely observational and only involves a predominantly white and well-educated population of elderly people.

Scientists advise consuming omega-3 fatty acids through natural foods, such as seafood and nuts, rather than supplements.