Omega-3 supplements are popular among many older adults to help combat age-related issues. They are often marketed as supporting cardiovascular health and reducing the risk of cognitive decline and dementia. However, a new study published in The Journal of Prevention of Alzheimer's Disease suggests that these oral capsules may actually be linked to a faster decline in cognitive function.
Many senior citizens swear by oral supplements and the benefits they bring. However, the scientific evidence is mixed. While animal and observational studies have indicated possible protective effects on the aging brain, controlled trials with humans have not shown such cognitive benefits.
To try to find definitive answers about whether the supplements actually slow cognitive decline, researchers from China used long-term patient data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) and studied highly detailed brain scans.
The omega-3 paradox
The study examined cognitive and brain imaging changes over five years in 273 omega-3 users and compared them with a control group of 546 non-users. These were matched for age, sex, genetics, and diagnosis.
The results revealed that participants taking omega-3 supplements showed a more rapid decline across the three primary cognitive assessments (MMSE, ADAS-Cog13, and CDR-SB) each person completed during the study.
This pattern remained the same regardless of genetics. Both groups had the same number of people with the APOE ε4 gene, which is associated with increased risk for Alzheimer's. This suggests the difference in decline was unlikely to be explained by this major genetic risk factor alone.
To see why this might be the case, the researchers studied brain scans to look for physical changes. The faster decline did not appear to be caused by the typical signs of Alzheimer's, such as the buildup of amyloid plaques or abnormal clumps of tau proteins.
Glucose and the aging brain
Instead, the scans revealed a significant drop in brain glucose metabolism, which the research team believes may be linked to omega-3 supplementation. This reduction is often associated with synaptic dysfunction, meaning that while the physical structure of the brain may remain relatively intact, communication between brain cells may be less efficient.
"Omega-3 supplementation may be associated with accelerated cognitive decline in older adults, potentially through adverse effects on cerebral synaptic function rather than classical AD proteinopathies," wrote the study authors in their paper.
The team points out that their results are not conclusive. This was an observational study, not a clinical trial, that identified an association rather than a definitive cause. Nonetheless, it's a correlation that needs further investigation.
"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."
This article was originally published on MedicalXpress Breaking News-and-Events.