Written By: N. Lothungbeni Humtsoe | Updated : May 5, 2026 1:54 PM IST
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Omega-3 supplements have been extensively marketed as a convenient supplement addition to a daily routine for supporting brain functions particularly as one ages. Millions of adults have been using fish oil, flaxseed and krill oil capsules to maintain memory, enhance concentration and lower the risk of memory loss. However a new study published in the Journal of Prevention of Alzheimer's Disease questions this long-held belief and it is possible that the relationship between omega-3 supplements and brain ageing is far more complex than previously thought.
Chinese researchers examined data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) a long-term project that monitored the health of the brain, its memory changes and the progression of Alzheimer's disease. The research investigated whether there was any quantifiable effect of omega-3 supplementation on cognitive decline and changes in the brain related to Alzheimer's over time.
The results were surprising as researchers found out that the intake of omega-3 supplements by the participants resulted in a faster cognitive decline in participants compared to nonparticipants across three commonly used scales: the Mini-Mental State Examination (MMSE), Alzheimer Disease Assessment Scale Cognitive Subscale (ADAS-Cog13) and Clinical Dementia Rating Sum of Boxes (CDR-SB).
Scientists claim that these findings contradict the generally accepted belief according to which omega-3 plays a protective role in the brain. Rather supplementation was found to be associated with a statistically significant decrease in cognitive decline.
A team of researchers examined about 1,814 elderly people on the basis of age, gender, status in terms of genetic predisposition (APOE 4 status) and medical condition. The final analysis involved 273 users and 546 nonusers of omega-3 who were followed between five and six years with mild cognitive impairment and those with Alzheimer's disease. The supplement use reported was mostly that of fish oil, but flax and krill oil were also covered.
Scientists found that memory and thinking scores decreased more quickly in research participants taking omega-3 as a supplement. Although the rate of deterioration was lower than the average annual deterioration observed in Alzheimer's disease the trend was still similar in the various cognitive tests.
"These findings challenge the prevailing view of omega-3 as uniformly beneficial and highlight the need for a cautious reassessment of its widespread use for cognitive protection," write the authors led by researchers at the Army Medical University in China. "From a clinical and public health standpoint, our findings suggest that a more nuanced assessment and further research are warranted."
Interestingly, brain imaging analysis provided one of the most interesting aspects of the study. The result showed that the accelerated cognitive impairment among omega-3 users was not associated with traditional Alzheimer markers like accumulation of amyloid plaques, buildup of tau proteins or loss of brain volume.
Rather the variation was found to be associated with individuals who have lowered glucose metabolism in certain regions of the brain. It was quantified with the help of FDG-PET scans which determine the effectiveness of brain cells in using energy. It is important to note that reduced brain functioning is commonly related to lower glucose metabolism. The brain imaging partially explained the relationship between the use of omega-3 and the cognitive decline in this study indicating that the use of energy in brain cells might have a role.
Although omega-3 fatty acids may still have an advantage this study highlights the importance of a more personalised and careful dietary plan regarding supplementation.
Differences in metabolism, genetic predisposition and brain energy use may influence how individuals respond to supplementation.
They may benefit some people but their effects can vary depending on individual factors like genetics and overall health.
Some evidence from recent research suggests certain individuals may experience faster decline though results are not conclusive.
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