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Omega-3 Fatty Acids: A Complete Guide To Why They're So Good For Inflammation & Brain Health

Darcy McDonough, M.S.
August 18, 2018
Darcy McDonough, M.S.
mbg Nutrition & Health Writer
By Darcy McDonough, M.S.
mbg Nutrition & Health Writer
Darcy McDonough is the Senior Manager, SEO & Content Strategy at mbg. She has a master’s degree in nutrition interventions, communication, and behavior change from the Tufts Friedman School of Nutrition Science and Policy.
Photo by Nadine Greeff
August 18, 2018

At this point, it's safe to say the low-fat '90s are 100 percent over. Thanks to a newfound understanding of "good" fat versus "bad" fat, avocados are on practically every menu, and health-conscious people are spiking their coffee with butter and coating their veggies in coconut oil. Given this sudden surge in "good" fat consumption, you may be surprised to find out more than 90 percent of Americans are deficient in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two types of "good" omega-3 fatty acids.

Found predominantly in fish, flaxseeds, and walnuts, omega-3 fatty acids are crucial for proper development, cardiovascular protection, and brain health. So why aren't we getting enough of this important nutrient? Here, we break down all the benefits of omega-3 fatty acids, why we don't get enough, and how to get more of 'em:

The basics: omega-6s versus omega-3s.

Omega-6 and omega-3 fatty acids are two types of polyunsaturated fat, also known as the "good" kind of fat. They are both essential fatty acids1, which means that our body cannot produce an adequate amount on its own, so we must rely on our diet to achieve optimal levels. Once ingested, omega-6 and omega-3 are both transformed into other important fatty acids in the body. Omega-3, typically consumed in the alpha-linolenic acid (ALA) form, is converted to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) by the body, while omega-6 is converted into arachidonic acid (AA). Omega-3 and omega-6 compete for enzymes2 in the body to help them perform these conversions. So if you are predominantly consuming only one type of fatty acid, it may inhibit the other one from getting enough access to the enzymes. This is why it is important to consume them in the correct ratio.

Most researchers agree the optimal ratio of omega-6 to omega-33 is about 2:1, but the average American consumes a ratio closer to 20:1—yikes. That's because omega-6s, found in vegetable oils, are super prevalent in the modern diet, while omega-3s are a bit tougher to find. Overconsumption of omega-6 coupled with underconsumption of omega-3 has created a drastically skewed ratio and widespread deficiency in DHA and EPA. Luckily, simple diet tweaks and supplementation can help you balance your omega fatty acids and improve your health.

The health benefits of omega-3s.

The lack of omega-3s in our diet is concerning because this kind of fat plays such a pivotal role in supporting overall health—from our hearts and our brains to our inflammatory response and our body's endocannabinoid production. Here are some of the major benefits of omega-3s and why it's a good idea to make sure you're getting enough.

Omega-3s support the endocannabinoid system.

The endocannabinoid system (ECS), a network of enzymes, receptors, and cannabinoids in our body, has been increasingly studied for its role in regulating pain, stress, anxiety, and inflammation. This "master regulatory system" interacts with compounds called cannabinoids that we produce naturally in our body (called endocannabinoids) or that we consume from plants (phytocannabinoids—like cannabis, which contains the well-known cannabinoids CBD and THC). These compounds bind to and activate cannabinoid receptors4 throughout the body, which are believed to be how the ECS mediates pain and bolsters the immune system.

The cannabinoids our body produces (endocannabinoids) are synthesized from omega-3s. Therefore, consuming enough omega-3s is crucial for maintaining adequate levels of endocannabinoids to keep the ECS functioning optimally. Additionally, the chemical reactions that convert omega-3s into cannabinoids have been shown to have anti-inflammatory benefits. Researchers believe that many of the anti-inflammatory health benefits of consuming omega-3s can be attributed to their role in supporting the ECS.

Omega-3s and heart disease.

You've likely already heard about the connection between omega-3s and heart health, and the important role they play in regulating and reducing triglycerides. Triglyceride levels are one of the key indicators of heart health and cardiovascular disease risk, along with HDL and LDL levels. High triglyceride levels have been associated with atherosclerosis5, the hardening of the arteries, which leads to heart attacks. Many studies have shown that omega-3s can help reduce triglyceride levels. In fact, the FDA has approved medications derived from omega-3-rich fish oil to treat extremely high triglyceride levels. Triglyceride lowering isn't the only way omega-3s can be heart healthy, though. The anti-inflammatory properties of omega-3s, via the aforementioned endocannabinoid system, may protect blood vessels6 from damage. Additionally, omega-3 supplementation has been found to slow resting heart rate7, which can be a risk factor for sudden cardiac death.

Omega-3 fatty acids have also been shown to be especially beneficial for individuals who have already experienced a cardiac episode. Studies have found that including fish oil8 or fatty fish9 in post-heart-attack care significantly reduced the risk of a second heart attack or sudden death. The evidence for omega-3s for preventive care in healthy individuals is less clear. Studies have shown that omega-3 supplementation can lower the risk of sudden cardiac death and that omega-3 consumption is associated with lower levels of cardiac disease, but other studies have shown little or no cardiac benefit from taking fish oil supplements. The American Heart Association only endorses the use of omega-3s for those who have suffered a recent heart attack. While the jury is still out on preventive care, it is clear omega-3s offer heart-healing benefits for those at high risk or who have experienced a cardiac episode.

Omega-3s and the brain.

The brain is mostly made up of fat—in fact, 60 percent of the dry weight of the brain is fat10, primarily the omega-3 fatty acid DHA. Consuming adequate amounts of both omega-6s and omega-3s is crucial for brain development, integrity, function, and maintenance. Researchers believe fatty acids protect cognitive function by maintaining the fluidity of cells in the brain, increasing synaptic activity,11 and acting as messengers12 to dictate the synthesis and function of neurotransmitters. To this point, one study13 found that elderly adults with the highest levels of DHA were 47 percent less likely to develop dementia.

Omega-3 deficiency, on the other hand, has been shown to impair cognitive function, learning, and memory. Knowing this, it probably won't surprise you to learn that studies have found that dementia patients have low omega-3 levels14. Omega-3 supplementation has not been able to successfully reverse dementia symptoms, but it may be able to protect healthy brains and delay cognitive decline in mild cases. In one study, healthy young adults with low dietary omega-3 consumption saw improvements in memory and recall reaction time15 when they supplemented with omega-3s. Additionally, omega-3 supplementation improved memory and learning in adults with mild cognitive decline. Getting enough omega-3s is an important way to protect and support brain health.

Omega-3s, inflammation, and depression.

Low omega-3 levels have been associated with chronic inflammation16, potentially contributing to depression symptoms. Chronic inflammation may trigger or exacerbate depression17 by interfering with cell signaling in the brain, inhibiting neurotransmitter production, and messing with the central nervous system. Additionally, omega-3 fatty acids are integral to the production of serotonin, "the happiness hormone"—meaning: Not getting enough omega-3s might contribute to depression in more ways than one. In fact, many patients with depression have been found to have increased levels of inflammation17 and low levels of omega-3s, furthering evidence of the connection between omega-3s and depression.

And now, some good news: Consuming omega-3-rich foods or supplements may offer protective, and even therapeutic, benefits against depression. Omega-3 fatty acids are a known anti-inflammatory and may regulate and inhibit the inflammatory cytokines associated with depression. In fact, one study found that individuals who had the highest intake of omega-3s had a 20 percent lower risk of depression16. Similar associations have been found between national fish consumption18 levels and depression rates. In terms of treating depression, results have been conflicted for omega-3 supplementation. Many studies19 have shown promising results, while others have found no effect. Differences in dosing, type of omega-3s used, and severity of depression may account for these disparities. Omega-3s are generally considered to alleviate mild to moderate depression symptoms when used in conjunction with other treatment therapies.

How to increase your omega-3 levels.

Foods high in omega-3s.

Photo: Nataša Mandić

It is always best to try to get all of your vitamins and nutrients from a balanced diet, something often referred to as a "food first" approach. On that note, some foods high in omega-3s include:

  • Salmon
  • Sardines
  • Halibut
  • Flaxseeds
  • Walnuts
  • Chia seeds
  • Soybeans

Omega-3 supplementation: dosages and side effects.

The American Heart Association20 recommends eating at least two servings of fish each week in order to maintain optimal omega-3 levels. If you are worried about mercury in fish, have dietary restrictions, or otherwise don't think you're getting enough omega-3s, supplements are a great option. Integrative neurologist, mbg Collective member, and author of the best-selling book Grain Brain, Dr. David Perlmutter, suggests 800 to 1,200 mg of DHA daily, and the USDA recommends1 a maximum of 2 grams daily. Be careful not to go overboard—there is such a thing as too much good fat. Also, although omega-3 supplements are considered safe, they do have some mild side effects, including fishy burps and indigestion. Always be sure to check with your doctor before starting a new supplement regimen because omega-3s may interact with other medications, especially anticoagulants.

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Darcy McDonough, M.S. author page.
Darcy McDonough, M.S.
mbg Nutrition & Health Writer

Darcy McDonough, M.S., is the Senior Manager, SEO & Content Strategy at mindbodygreen. She holds a master’s degree in nutrition interventions, communication, and behavior change from Tufts Friedman School of Nutrition Science and Policy. She has previously worked in nutrition communications for Joy Bauer, the nutrition and health expert for NBC’s TODAY Show.

McDonough has developed & lead nutrition education programming in schools. She’s covered a wide range of topics as a health & nutrition reporter from the rise in the use of psychedelics for depression to the frustrating trend in shorter doctors' appointments and the connection between diet and disease.