Omega-3 Fatty Acids for Brain Health

Dr. David Wiss

November 16, 2021

Mental Health

Omega-3 fatty acids are polyunsaturated fatty acids that have been popularized in the form of fish oil supplementation. Seafood remains the best source of omega-3, but other sources include walnuts, flaxseeds, and chia seeds. Omega-3 is considered essential because the body cannot produce these compounds from other lipid structures, therefore, they must be obtained from food or supplements. Algae supplements are becoming popular as plant sources of omega-3 among those who choose not to consume fish or don’t enjoy it.

Omega-3 has received considerable attention for its anti-inflammatory properties (through eicosanoid pathways), however, it has not lived up to its hype in preventing cardiovascular disease [1]. Comprehensive reviews of the available data have suggested that the protective effect of omega-3 on cardiovascular outcomes increases with dosage [2]. Importantly, it may be the ratio of omega-3 to omega-6 that matters most, which is not easy to control in long-term clinical trials. It is critical to remember that the observable effects of omega-3 are largely dependent on the outcome measure used, and other control measures in the study.

Inconsistencies in the medical literature have left many clinicians and consumers confused. Many trials have been conducted on various chronic conditions, but research has shifted focus toward mental health outcomes. 


Does Omega-3 Have an Impact on Mental Health?

Before answering, let us cover some of the basics so you know what to look for. In fish oil supplements or other non-marine sources of omega-3 (e.g., flax oil) one can expect to see milligram counts for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These are the essential and sought-after omega-3 compounds that confer health benefits, particularly if one is deficient. Many research studies have tried to determine which fatty acid is more beneficial, and the findings are mixed. Some evidence suggests that EPA by itself is protective of cardiovascular health, whereas combined EPA+DHA had no effect [3]. Meanwhile, DHA may be more beneficial for brain health and cognitive function, particularly throughout childhood and adolescence [4]. 


Which Form of Omega-3 is More Important for Mental Health?

EPA is converted to DHA in the body, yet many experts agree that both should be present in supplemental form. When looking to add omega-3 nutrition, make sure you are getting at least 1.5g (1,500mg) of EPA and DHA combined, and do not be fooled by supplements that offer grams or milligrams of total oil rather than total EPA and DHA content. For example, 3g of fish oil does not mean 3g of EPA/DHA. Some products have higher concentrations of EPA/DHA than others. This is generally one way to evaluate the quality of the product.

Deficiencies in omega-3 have been linked to aggressive behaviors, impulsivity, and attention deficit hyperactivity disorder (ADHD) [5,6]. Deficiencies have also been implicated in increasing vulnerability to alcohol and drug use disorders. Supplementation appears helpful in reducing neuroinflammation [7,8]. Omega-3 fatty acids are often recommended in the nutritional management of substance use disorders, and in “lifestyle medicine” approaches for anxiety disorders. This concept of using the diet for anxiety management is becoming increasingly popular. 

Marine-based omega-3 supplementation show promise in improving symptoms of borderline personality disorder (BPD) [9]. Higher intakes of omega-3 have been linked to decreased risk for depressive symptoms [10,11]. It appears that EPA is more responsible for this effect [12]. Investigators who have described similar links between omega-3 and anxiety propose that DHA does not readily cross the blood-brain barrier compared to EPA [13]. While DHA is critical for brain health, EPA is a precursor and, therefore may be the more important ingredient in supplementation.



More research is needed to identify the optimal type and dose of omega-3 supplementation for various mental health conditions. In the meantime, our recommendation of at least 1.5g (1,500mg) of EPA and DHA combined is sound. Currently, it is hard to know the optimal ratio of EPA:DHA for behavioral health, and it likely varies from person to person based on individual conversion capacity. The best practice is to favor higher amounts of EPA rather than DHA. Supplementation plus regular intake of fatty fish, walnuts, flaxseed, and chia should do the trick! Also, storage of supplementation is critical: avoid heat and light, and never use supplements that have expired—your brain will thank you!

Welcome to the wonderful world of nutritional psychiatry, where food, supplements, and nutraceuticals are used to improve mental health symptoms. It is not imperative to eliminate ultra-processed foods but it is important to focus on anti-inflammatory eating by consuming a diet high in polyphenols and omega-3 fatty acids. Reducing inflammation can be done through the Mediterranean Diet and we can teach you the steps to move in that direction. Meanwhile, the most important thing is to eat in a way that is sustainable to you and culturally appropriate. You can always incorporate principles into your current nutrition regimen and see how it impacts your quality of life. 


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