Fish Oil and Brain Health

Omega-3 fatty acids are known for cardiovascular benefits, such as lowering triglycerides and reducing inflammation.^1-5

A meta-analysis found that people with the highest consumption of EPA and DHA (omega-3s in fish oil) have an associated 14% reduction in risk of death from any cause, compared to the lowest consumption.⁶

In addition, fish oil’s effect on brain health continues to make headlines. Here are a few recent highlights.

Protection Against Neurotoxins

A study published in the journal Neurology added to the evidence that omega-3s protect against neurotoxins, substances that damage the brain or nervous system.⁷

More than 1,300 elderly women underwent a brain MRI. In order to determine how much pollution exposure these women had, researchers used their addresses to assess their exposure to a category of air pollution (called PM^2.5) for the three years prior to the MRI. This is known as a using a spatiotemporal model.

PM^2.5 is known to have neurotoxic effects. Exposure is associated with smaller white matter volumes, which have been linked to strokes, cognitive decline, and dementia.^8,9

The researchers examined the association between omega-3 blood levels and PM^2.5 exposure with brain volumes.

Results showed that women with higher levels of omega-3 fatty acids had significantly greater volumes of hippocampus (an area of the brain associated with cognition and memory) and white matter (which contains the nerve fibers that connect brain cells).

Importantly, higher omega-3 levels reduced the negative connection between PM ^2.5 exposure and white matter volumes in the total brain and in specific brain areas (frontal, parietal, and temporal).

These results indicate that women with higher levels of omega-3 fatty acids were protected against the brain-damaging effects of PM ^2.5 exposure.

Improved Depression Symptoms

In a meta-analysis published in Translational Psychiatry, researchers found that taking a daily omega-3 fatty acid supplement with a high ratio of EPA to DHA significantly improved symptoms of mild to moderate depression (including depressed mood, sleep problems, and fatigue) in pregnant and postpartum women.¹⁰

Omega-3 doses of the studies included ranged from 1 gram to 6 grams daily. These dosages were all well-tolerated.

Better Stroke Outcomes

Several animal studies have found that resolvins (anti-inflammatory mediators the body produces from DHA and EPA) decreased brain damage caused by a stroke, and reversed stroke-induced neurological dysfunction.¹¹

Protecting Brain Structure

Omega-3 fatty acids are a key structural component of all cell membranes.

Brain cell membranes are especially rich in EPA/DHA.¹²

Electrical signals generated in brain cell membranes play a role in everything from simple movement, to language, reasoning, memory formation, and recall.

These signals cannot be conducted properly without myelin, which insulates the fibers of nerve cells.¹³

Omega-3s are an essential structural component of the myelin sheaths that cover nerve fibers.¹⁴

Preclinical data indicate that omega-3 intake impacts levels of brain growth factors that support the survival, development, and adaptability of neurons.^15-17

A laboratory model study of Alzheimer’s disease found that even short-term omega-3 intake improved the function of brain cells in animals that had not yet developed dementia symptoms.¹⁸

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References

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11. Tulowiecka N, Kotlega D, Prowans P, et al. The Role of Resolvins: EPA and DHA Derivatives Can Be Useful in the Prevention and Treatment of Ischemic Stroke. Int J Mol Sci. 2020 Oct 15;21(20).
12. Surette ME. The science behind dietary omega-3 fatty acids. CMAJ. 2008 Jan 15;178(2):177-80.
13. Available at: https://www.ncbi.nlm.nih.gov/books/NBK10921/. Accessed December 2, 2021.
14. Chen S, Zhang H, Pu H, et al. n-3 PUFA supplementation benefits microglial responses to myelin pathology. Sci Rep. 2014 Dec 12;4(1):7458.
15. Jiang LH, Shi Y, Wang LS, et al. The influence of orally administered docosahexaenoic acid on cognitive ability in aged mice. J Nutr Biochem. 2009 Sep;20(9):735-41.
16. Wu A, Ying Z, Gomez-Pinilla F. Docosahexaenoic acid dietary supplementation enhances the effects of exercise on synaptic plasticity and cognition. Neuroscience. 2008 Aug 26;155(3):751-9.
17. Knochel C, Voss M, Gruter F, et al. Omega 3 Fatty Acids: Novel Neurotherapeutic Targets for Cognitive Dysfunction in Mood Disorders and Schizophrenia? Curr Neuropharmacol. 2015;13(5):663-80.
18. Jovic M, Loncarevic-Vasiljkovic N, Ivkovic S, et al. Short-term fish oil supplementation applied in presymptomatic stage of Alzheimer’s disease enhances microglial/macrophage barrier and prevents neuritic dystrophy in parietal cortex of 5xFAD mouse model. PLoS One. 2019;14(5):e0216726.