Omega-3 fatty acids are polyunsaturated fatty acids (PUFAs), a type of essential fat involved in several metabolic processes. They are a crucial component of good health. Research shows that omega-3 fatty acids reduce inflammation and may reduce the risk of chronic diseases such as heart disease, cancer, and arthritis—conditions that often have a high inflammatory process at their root. But perhaps most impressive is the research that confirms the benefits of omega-3s on the brain.
There are 11 types of omega-3s, but the most well-known for their beneficial properties are alpha-linoleic acid (ALA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA).
Dietary sources of ALA, DHA, and EPA
The modern American diet is typically low in omega-3 and high in omega-6 fatty acids (another form of polyunsaturated fatty acid). Too much omega-6 causes inflammation, but interestingly enough, too much omega-3 can also be bad; it's all about keeping the ratio of omega-3:omega-6 in check.
A well-balanced diet with natural sources of ALA, DHA, and EPA is fundamental to maintaining a healthy ratio that prevents inflammation and promotes long-term health.
ALA comes from plants and is the most largely consumed form of omega-3 in the typical American diet. It serves as an energy source for our cells, and a small percent is converted into DHA and EPA. Dietary sources of ALA include flaxseeds and flax oil, walnuts and walnut oil, chia seeds, pumpkin seeds, hemp seeds and hemp oil, mustard oil, most leafy green vegetables, and tofu. Some research is being done on algal oil, as it may be more bioavailable, meaning it will be easier to absorb and converts easily to DHA in the body. One study found micro-algae were able to increase blood erythrocyte and plasma DHA, a marker of absorption. For vegans and vegetarians, this may be a promising alternative to fish oils. Some supplement brands have already started creating vegetarian EPA/DHA supplements from algal oil for those who prefer not to take fish oils.
DHA and EPA are found in fatty, cold-water fish, such as salmon, trout, cod liver, herring, mackerel, and sardines; shellfish such as shrimp, oysters, clams, and scallops. These sources of omega-3 are most bioavailable. However, it's important to purchase wild caught fish and check out seafoodwatch.org to see which fish are lowest in mercury and other environmental toxins. A balance of sources from plants and seafood will help you find the right balance of these essential fatty acids.
When diets don't meet the mark, supplementation may be recommended but should always be done under the supervision of a doctor and dietitian for these reasons:
- A doctor and/or a dietitian-nutritionist can monitor the ratio of omega 3:6. Certain health conditions may benefit from additional omega-3; in this case, proper dosage should be determined by a doctor.
- When a diet is already rich in omega-3, supplementation may throw a proper omega 3:6 ratio off-balance and unintentionally cause inflammation.
- There are some supplements of omega-3 that are actually inflammatory. Many retail brands of omega-3 or fish oils come from sources of fish that are fed an atypical diet of corn and soy, which alters the composition of fatty acids in the fish oil. This can cause inflammation. As supplements do not require FDA approval, a dietitian or doctor can recommend a trusted brand.
Effects of Omega-3 Fatty Acids on the Brain
Research shows that omega-3 fatty acids can be effective in treating depressive conditions, such as major depressive disorder or bipolar disorder.
Post-stroke & post-concussion
A recent study found that giving DHA post-concussion helps in the repair and recovery from injury. A 2015 study found evidence that supported the clinical use of omega-3 in treating "stroke and other acute neurological diseases" due, in part, to its anti-inflammatory and anti-apoptotic (prevention of cell death) properties.
Neuropathic pain, or pain due to damage of the peripheral or central nervous system, can cause debilitating pain for those affected. In 2010, a review of case studies found that patients with neuropathic pain who were treated with high doses of omega-3 fish oil had "clinically significant pain reduction" and improved function.
Diets high in omega-3 fatty acids have been found to lessen the frequency and occurrence of migraine headaches.
DHA is extremely important for brain development and function. Studies show that when DHA levels are low, the brain is more susceptible to degeneration. Omega-3 fatty acids help scavenge free radicals (atoms, molecules, or ions with unpaired electrons) that attach inappropriately to tissue and damage it.
A recent study found that "omega-3 polyunsaturated fatty acids, which are found in fish oil, could improve the function of the glymphatic system, which facilitates the clearance of waste from the brain, and promote the clearance of metabolites including amyloid-β peptides, a primary culprit in Alzheimer's disease.”
Improved cognitive performance
Studies also show that DHA supplementation can improve cognitive performance.
How much is enough?
Eating a Mediterranean diet with plenty of fruits, vegetables, whole grains, nuts, lean meat, and cold-water fish will help a person consume more omega-3s on a regular basis. Current literature advises that at least two 3.5-oz. portions of oily fish should be eaten weekly. Determining the correct intake of omega-3 fatty acids depends on an individual's age, overall state of physical and mental health, and whether there is a history of trauma that suggests heightened inflammation. To find out the amount that is best for your unique condition, make sure to consult with your health care provider.
This article as co-authored by Vanessa Berenstein, M.A., R.D..