Omega-3 fatty acids lower risk of dementia, cognitive decline

Omega-3 polyunsaturated fatty acid intake provides neurological benefits by reducing the risk of Alzheimer’s disease (AD) or cognitive decline in older adults, reports a study.

The authors obtained longitudinal data from 1,135 participants without dementia (mean age 73 years) in the Alzheimer’s Disease Neuroimaging Initiative (ADNI) to explore the relationship of omega-3 fatty acid supplementation and blood biomarkers with incident AD during follow-up at 6 years.

In addition, a meta-analysis of cohort studies was conducted to examine the longitudinal associations of omega-3 dietary intake and its peripheral markers with all-cause dementia or cognitive decline. Finally, the authors performed causal dose‒response analyses using a robust error meta-regression model.

Long-term use of omega-3 fatty acid supplements in the ADNI cohort resulted in a 64-percent decrease in AD risk (hazard ratio, 0.36, 95 percent confidence interval [CI], 0.18‒0.72; p=0.004).

Following the inclusion of 48 longitudinal studies involving a total of 103,651 participants, the authors found a moderate-to-high level of evidence for a 20-percent reduced risk of all-cause dementia or cognitive decline with dietary intake of omega-3 fatty acids, particularly for docosahexaenoic acid (DHA) intake (relative risk [RR], 0.82; I², 63.6 percent; p=0.001) and for studies adjusted for apolipoprotein APOE ε4 status (RR, 0.83; I², 65 percent; p=0.006).

Every 0.1-g/day increase in DHA or eicosapentaenoic acid (EPA) intake also contributed to about 8 percent to 9.9 percent decrease in the risk of cognitive decline (p<0.0005). Moderate-to-high levels of evidence suggested that higher levels of plasma EPA (RR, 0.88; I², 38.1 percent) and erythrocyte membrane DHA (RR, 0.94; I², 0.4 percent) correlated with a lower cognitive decline risk.

“Dietary intake or long-term supplementation of omega-3 fatty acids may help reduce risk of AD or cognitive decline,” the authors said.