Fish Oil for Depression and Anxiety: The Underdog Supplement

Many of us know that fish oil is beneficial in the prevention and treatment of cardiovascular and metabolic diseases, such as conditions of high lipids and high blood sugar. We’ve also heard that it is anti-inflammatory and, therefore, may be helpful in autoimmune conditions like rheumatoid arthritis or autoimmune thyroid disease.

However, you may be surprised to hear that fish oil is one of my favorite nutritional and supplemental recommendations for my patients with depression and anxiety. I consider it the underdog supplement for mental health.

Supplements like St. John’s Wort and L-theanine for treating mental health are well-known for their direct effects on important neurotransmitters like serotonin and GABA. So how does fish oil compare to popular supplements like these, what does it do, and how does it work? 

Well first, let’s learn a little bit about the foods we eat. 

The standard American diet is chalk full of omega-6 fatty acids. From foods like processed meats and snack chips to vegetable and canola oils used in cooking, omega-6 fatty acids are found everywhere and are consumed in significantly large amounts daily by the average American. These fatty acids are precursors to pro-inflammatory molecules². 

Omega-3 fatty acids, on the other hand, are harder to come by. We still eat them in things like seafood, olive oil, and flax seeds, but not at nearly high amounts. These are precursors to the anti-inflammatory molecules EPA and DHA².

How does this relate to mental health? 

Studies with omega-3 fatty acids have been shown to decrease anxiety, enhance memory and focus, and improve depressive symptoms³. They work by improving our nervous system function and by decreasing inflammation in the nervous system. 

EPA and DHA are healthy for our cell membranes. They improve how we transmit signals with neurotransmitters, such as dopamine, GABA, and serotonin, which are implicated in anxiety and depression³. 

Lastly, mental health conditions have also been associated with inflammation in the nervous system³, which can be ameliorated by decreasing intake of the pro-inflammatory omega-6 fatty acids and increasing the anti-inflammatory omega-3’s.

How can you apply this to your life?

It is always important to start with your diet before considering supplementation. 

• Eat foods high in omega 3’s like wild-caught salmon, herring, trout, flax seeds, flax oil, and olive oil. Wild-caught salmon has a significantly better percentage of omega-3’s than farmed salmon. 
• Decrease all processed and packaged foods, especially deli meats and foods cooked with peanut and canola oils. Important note: omega-6 fatty acids still have some health benefits. It is the high quantitythat makes them something to watch out for. There are still healthy foods that are high in omega-6’s such as nuts and seeds.

If you have anxiety or depression, high doses of supplemental fish oil (3-16 grams daily) may be warranted to see clinical benefit⁴.  

Please consult your doctor before initiating any changes to your nutrition or supplementation regimen. Fish oil can interact with medications like blood thinners and supplementation is not appropriate for all cases. This is not medical advice and not meant to replace standard of care.

1. Kiecolt-Glaser JK, Belury MA, Andridge R, Malarkey WB, Glaser R. Omega-3 supplementation lowers inflammation and anxiety in medical students: a randomized controlled trial. Brain Behav Immun. 2011;25(8):1725-1734. doi:10.1016/j.bbi.2011.07.229
2. Liput KP, Lepczyński A, Ogłuszka M, et al. Effects of Dietary n-3 and n-6 Polyunsaturated Fatty Acids in Inflammation and Cancerogenesis. Int J Mol Sci. 2021;22(13):6965. Published 2021 Jun 28. doi:10.3390/ijms22136965
3. McNamara RK, Strawn JR. Role of Long-Chain Omega-3 Fatty Acids in Psychiatric Practice. PharmaNutrition. 2013;1(2):41-49. doi:10.1016/j.phanu.2012.10.004
4. McNamara RK, Strimpfel J, Jandacek R, et al. Detection and Treatment of Long-Chain Omega-3 Fatty Acid Deficiency in Adolescents with SSRI-Resistant Major Depressive Disorder. PharmaNutrition. 2014;2(2):38-46. doi:10.1016/j.phanu.2014.02.002