The Army Medical University in China conducted research showing that omega-3 supplements do not protect the brain health of the elderly, as the study found that participants with a genetic risk for Alzheimer’s who took the supplements experienced faster cognitive decline than those who did not take the supplements.
The researchers studied health information from more than 800 participants in the Alzheimer’s Disease Neuroimaging Initiative (ADNI), including about 50 percent of the group who carried the APOE ε4 gene, which has been identified as a risk factor for dementia.
Among those taking 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 in plaques, tangles, or gray matter.
The decline instead correlated with changes in the neuronal synaptic function of the connections between brain cells. “Our results suggest that omega-3 supplementation may negatively impact synaptic integrity in some contexts, ultimately negating its short-term benefits,” the authors explain.
The results do not confirm that omega-3 consumption causes cognitive impairment, but they do show that there is an ideal dosage to obtain maximum benefits. A 2025 systematic review concluded that low doses of omega-3 supplements improve cognitive function, while doses higher than 1,500 milligrams per day have a detrimental effect on the brain.
“Such findings contradict the widely held view about the benefits of omega-3 and require consideration of a more cautious approach to the use of 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 older adults.
Scientists recommend consuming omega-3 fatty acids through natural foods, such as seafood and nuts, rather than through supplements.
