How DHA Omega-3 Fatty Acid Affects the Brain

The brain is one of the most complex organs in the body, and it’s no small feat to keep it running optimally. And although your brain only accounts for two percent of your body’s mass, it consumes 20 percent of your body’s energy.1 A large portion of the brain is made up of organic compounds called long-chain omega-3 polyunsaturated fatty acids (PUFAs). Because PUFAs are present in great numbers, they play a crucial role in how the brain develops in infancy and how it ages. One PUFA in particular, docosahexaenoic acid (DHA), plays an essential role in cognitive function.* DHA: A Brain Building Block* Of the three main omega-3s in the human body – DHA, alpha-linolenic acid (ALA), and eicosapentaenoic acid (EPA) – DHA accounts for more than 90 percent of the PUFAs in the brain. DHA is especially abundant in the gray matter – the part of the brain that, among other functions, helps retain memories and control movement.1 The frontal and prefrontal lobes of the brain rely heavily on an optimal DHA level. These lobes are responsible for your ability to plan, problem solve, and pay attention, as well as for your emotional, social, and behavioral development. DHA, EPA, and their byproducts (metabolites) also influence blood flow within the brain, the chemical messengers that keep your body running (neurotransmitters), and other brain-related activities, such as making new neurons (nerve cells).*1 DHA Food Sources The body can't produce omega-3s on its own. Although it can convert some ALA to DHA, the amount is very small. ALA is found mainly in plant-based foods, such as kale, spinach, walnuts, flax seed oil, hemp seeds, edamame, avocadoes, and oatmeal. Consuming foods and supplements that contain DHA is the only practical way to increase its level in the body. The most common source of DHA is fish. Fatty fish, such as salmon, herring, mackerel, and sardines, contain some of the highest amounts, while less fatty fish, such as cod and tilapia, have lower amounts.2,3 You can also find DHA in fortified products, including certain brands of eggs, yogurt, and milk, and in nutritional supplements. Some of the most common supplements contain fish oil, krill oil, or cod liver oil. Vegetarians can find DHA in algal (algae) oil and seaweed products.2 Sources of DHADHA amount (in grams)Fish oil from salmon (1 tablespoon)2.48Farmed or wild Atlantic salmon, cooked (3 ounces)1.24 (farmed) 1.22 (wild)Atlantic herring, cooked (3 ounces)0.94Atlantic sardines, canned in oil, drained with bone (1 cup)0.76Atlantic mackerel, cooked (3 ounces)0.59Canned pink salmon, drained (3 ounces)0.63Sea bass, cooked (3 ounces)0.47Wild rainbow trout, cooked (3 ounces)0.44Anchovies, canned in oil, drained (1-ounce boneless)0.37Tuna, light, canned in water, drained (3 ounces)0.17 Source: USDA National Nutrient Database for Standard Reference2,4 DHA: Impact on Cognitive Function Research indicates that an overall healthy diet that includes omega-3s positively impacts brain function and might even decrease the risk for neurodegenerative conditions. The Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet is a style of eating that emphasizes healthful foods and incorporates omega-3s in the form of fatty fish. In one study, the MIND diet was associated with a 53-percent lower risk of Alzheimer’s disease.5 Research on omega-3s points to other possible benefits as well. A systematic review and meta-analysis of 25 studies suggests that supplementing with omega-3s might support memory in healthy individuals without dementia*6 Another study found that women with low levels of omega-3s in their blood scored lower on cognitive tests measuring attention than women with higher levels of omega-3s.7 However, it’s important to note that the women who scored lower still ranked within normal range. Because there are no conventional treatments for cognitive decline, there’s significant interest in whether omega-3s can help mitigate its progression.* Some research has found that individuals with cognitive decline tend to have lower levels of DHA.* In addition, higher levels of DHA seem to help preserve brain volume.* Some studies suggest that DHA is protective and beneficial when consumed earlier in life, before cognitive problems develop.8 To date, however, there is no research that indicates omega-3s can treat or prevent the signs and symptoms of dementia in humans. It's possible that DHA might help the brain indirectly by supporting healthy cardiovascular function.* Heart disease and dementia often co-exist in older adults. Supplementing with DHA has been linked to maintenance of healthy arteries and triglyeride levels.* Supplementation is also associated with supporting verbal fluency in an aging population.*2,9 It's important to keep in mind that, although many studies are encouraging, not all research confirms the same results. More studies are needed to clarify and determine the potential beneficial effects of DHA on human cognition. Important Considerations Before Increasing DHA While researchers sort out the influence of omega-3s on cognition, experts recommend an adequate amount for your overall health. There’s no recommended daily intake for omega-3s such as DHA, nor is there a known minimum level the body needs to maintain normal brain function. However, experts recommend consuming at least eight ounces of fatty fish per week.2 If you don’t have a diet high in fatty fish, then you might consider taking a fish oil supplement. A typical dose is 1 to 3 grams of DHA-EPA. Omega-3 supplements are generally well-tolerated when taken as recommended. However, if you are taking a medication, then it’s best to check with your health-care practitioner before taking a supplement, because there might be potential interactions. For example, fish oil can increase blood clotting time, so you might need to avoid taking fish oil if you’re on an anti-clotting drug, such as warfarin.2,5 Keep in mind that no single component of your diet or lifestyle is a cure-all. Not smoking, getting sufficient sleep, exercising, eating ample amounts of fruits and vegetables, and mind-body exercises, such as yoga and meditation, will help keep your brain healthy. A Word from Thorne When choosing an omega-3 supplement, it is important to find a trusted supplier that tests every product to ensure the absence of contaminants, including heavy metals, signs of oxidation, etc. Explore Thorne’s omega-3 products, including the newest addition – Advanced DHA, containing 650 mg DHA and 200 mg EPA per 2 softgels. References

1. Weiser MJ, Butt CM, Mohajeri MH. Docosahexaenoic acid and cognition throughout the lifespan. Nutrients 2016;8(2):99.

2. Omega-3 fatty acids: Fact sheet for health professionals. National Institutes of Health Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/. [Accessed May 24, 2022]

3. What are Omega-3 fatty acids? Academy of Nutrition and Dietetics. https://www.eatright.org/food/vitamins-and-supplements/types-of-vitamins-and-nutrients/what-are-omega-3-fatty-acids. [Accessed May 24, 2022]

4. Nutrients: DHA. USDA National Nutrient Database for Standard Reference. https://ods.od.nih.gov/pubs/usdandb/DHA-Content.pdf. [Accessed May 24, 2022]

5. Rakel D, ed. Chapter 11: Alzheimer’s Disease. In: Integrative Medicine. 4th ed. Elsevier; 2018. https://www.clinicalkey.com. [Accessed May 24, 2022]

6. Alex A, Abbott KA, McEvoy M, et al. Long-chain omega-3 polyunsaturated fatty acids and cognitive decline in non-demented adults: a systematic review and meta-analysis. Nutr Rev 2020;78(7):563-557.

7. Cook RL, Parker HM, Donges CE, et al. Omega-3 polyunsaturated fatty acids status and cognitive function in young women. Lipids Health Dis 2019;18(1):194.

8. Wood A, Chappell H, Zulyniak M. Dietary and supplemental long-chain omega-3 fatty acids as moderators of cognitive impairment . . . . Eur J Nutr 2022;61(2):589-604.

9. Heath RJ, Wood TR. Why have the benefits of DHA not been borne out . . . ? A narrative review focused on DHA metabolism and adipose tissue. Int J Mol Sci 2021;22(21):11826.