Omega-3 fats and cognitive decline: What you need to know

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This review aims to provide an updated understanding of the role of omega-3 polyunsaturated fatty acids (n-3 PUFA) in preventing cognitive decline and dementia.

Recent findings from prospective studies and meta-analyses have shed light on the potential benefits of fish consumption and n-3 PUFA intake in reducing the risk of mild cognitive decline and Alzheimer’s disease.

This review summarizes the key findings, including the effects of n-3 PUFA supplementation and potential factors influencing outcomes.

Omega-3 Fatty Acids and Cognitive Decline

Several studies have indicated that consuming fish or foods rich in n-3 PUFA may have a protective effect against cognitive decline and Alzheimer’s disease.

Randomized controlled trials (RCTs) focusing on people with mild cognitive impairment have shown that supplementation with a specific n-3 PUFA called docosahexaenoic acid (DHA) can help slow down cognitive decline.

However, the benefits of n-3 PUFA supplementation in individuals with Alzheimer’s disease have been less conclusive.

Role of n-3 PUFA in Cognitive Aging

In individuals with clinical coronary artery disease (CAD), research suggests that a daily intake of 3.36 grams of eicosapentaenoic acid (EPA) and DHA, both n-3 PUFA, can slow down cognitive aging by approximately 2.5 years.

This finding highlights the potential of n-3 PUFA in preserving cognitive function in specific populations.

Variability in Research Outcomes

RCTs conducted on cognitively healthy individuals aged over 55 years have produced mixed results regarding the benefits of n-3 PUFA supplementation.

While some studies reported positive effects on cognitive function, others did not show strong  benefits.

Various factors may contribute to these inconsistencies, including differences in dosage, trial duration, genetic factors (such as the apolipoproteinE genotype), sex, stage and rate of cognitive decline, cognitive testing methods, and individual characteristics.

Exploring Mechanisms: Neuroprotectin D1

One potential mechanism underlying the beneficial effects of n-3 PUFA, particularly DHA, is the production of neuroprotectin D1.

This compound, derived from DHA, may play a role in protecting brain health and function.

Summary and Recommendations

Based on the current evidence, people with early memory complaints, a family history of dementia, or clinical CAD should be advised about the potential benefits of consuming fish and considering n-3 PUFA supplementation.

ApolipoproteinE4 carriers, a genetic risk factor for Alzheimer’s disease, may particularly benefit from DHA supplementation before the onset of cognitive decline.

However, it is important to consider the variability in outcomes seen across studies and the influence of factors such as dosage, trial duration, and individual characteristics.

Further research is needed to better understand the optimal strategies for utilizing n-3 PUFA in preventing cognitive decline and dementia.


Omega-3 fatty acids, specifically n-3 PUFA, have shown promise in reducing the risk of cognitive decline and Alzheimer’s disease.

Fish consumption and n-3 PUFA supplementation, particularly with DHA, have demonstrated beneficial effects in people with mild cognitive impairment and clinical CAD.

However, more research is required to better understand the optimal dosages, duration of supplementation.

Overall, incorporating n-3 PUFA-rich foods into the diet and considering supplementation may offer potential cognitive benefits, but personalized approaches and further research are needed for precise recommendations.

The study was published in Current Opinion in Lipidology.

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