Omega-3 fatty acids (omega-3s) are a type of polyunsaturated fat important for building cells in your eyes and brain. They also help in the functions of your heart, lungs, blood vessels, and more. Your body can't effectively make these fatty acids on its own, so you need to get them through your diet.
There are three main types of omega-3 fatty acids: docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and alpha-linolenic acid (ALA). DHA and EPA are mostly found in seafood, while ALA can be found in certain plant foods.
Your body can start using DHA and EPA immediately to perform critical functions, but it converts ALA into DHA and EPA for use.1 However, the conversion rate is very low. The body only converts about 7-21% of ALA into EPA and about 0.01-1% of ALA into DHA.
Because of this low conversion rate, the most effective way to reach and maintain healthy omega-3 fatty acid levels is to consume foods rich in DHA and EPA or to take supplements that contain DHA and EPA, like fish oil, krill oil, and algal oil supplements.
For the same reason, much of the research around the benefits of omega-3 fatty acid supplements is done on supplements providing DHA and EPA, not ALA.
Could Support Heart Health
Omega-3 fatty acids can help protect cardiovascular health because they may help lower inflammation, blood lipid levels, and blood pressure. Omega-3 supplements may also help improve blood flow, increase levels of heart-protective HDL cholesterol, and support a healthy heart rate.
An analysis of research from 13 studies involving 127,477 participants found consuming EPA and DHA omega-3 supplements was associated with a significantly lower risk of heart attack, coronary heart disease, and total heart disease. It was also associated with a lower risk of death caused by heart disease.
The researchers also found taking higher-dose omega-3 supplements was linked to greater cardiovascular benefits. Every 1,000 mg per day dose of EPA and DHA corresponded to 9% lower risk of heart attack and 7% lower risk of total coronary heart disease.
May Improve Inflammation Symptoms
EPA and DHA omega-3 fatty acids help regulate inflammation in the body by influencing the inflammatory response and reducing levels of some inflammatory proteins.
High-dose omega-3 supplements have been shown to improve symptoms related to certain inflammatory conditions, such as rheumatoid arthritis (RA) and inflammatory bowel disease (IBD).
A review of research found consuming omega-3 fatty acid supplements significantly reduced pain in people with rheumatoid arthritis. Most of the included studies used doses ranging from 1.5 to 4 grams of combined DHA and EPA per day.
Research also shows taking omega-3 fatty acid supplements could help reduce intestinal inflammation, decrease disease activity, and improve the quality of life in people with IBD, including people with ulcerative colitis.
However, researchers in both cases noted more, higher-quality evidence was needed to confirm these benefits.
Could Support and Improve Brain Health
Omega-3 fatty acids are essential to neurological health and play an important role in brain development and function.
Studies show supplementing with omega-3 fatty acids may help protect against cognitive decline and promote healthy brain functioning in older and younger populations.
For example, in a review of 82 randomized control trials, 43.6% of the included studies reported a positive cognitive outcome after supplementation with omega-3s compared to placebo treatment.
Among the studies conducted on older adults with mild cognitive impairment, 66.7% reported a positive cognitive outcome related to omega-3 supplementation compared to placebo treatments.
Omega-3 supplements have also been shown to improve brain function, such as memory and attention, in older adults and children.
Additionally, omega-3s play an important role in brain development, which is why most experts recommend people who are pregnant supplement with omega-3s throughout pregnancy in order to maintain optimal blood levels of DHA and EPA to support fetal development.
May Help Treat Depression Symptoms
Taking omega-3s may help improve symptoms of depression.
A review of studies including 2,160 participants found omega-3 supplementation showed an overall beneficial effect on depressive symptoms.
Based on the included studies, the researchers concluded omega-3 formulations containing 60% or more EPA and supplements containing one or more grams of EPA per day were most effective.
Has Potential to Improve Other Conditions
Omega-3 fatty acids have protective effects on heart and brain health as well as anti-inflammatory properties. Because of this, researchers have looked at the use of omega-3 fatty acid supplements for complementary treatment of many physical and neurological conditions.
Some research has found evidence suggesting omega-3 supplements may benefit people with various health conditions when used along with primary treatments. These conditions include:
- Type-2 diabetes
- Parkinson’s disease
- Attention-deficit/hyperactivity disorder (ADHD)
Good Sources of Omega-3 Fatty Acids
While omega-3 deficiency is rare in the United States, many people have insufficient levels of the fatty acid. This may be because the average American diet is low in omega-3-rich foods.
EPA and DHA are mainly found in seafood, while ALA is found in certain plant foods. Here are the best sources of DHA, EPA, and ALA.
- Flax oil: 7.26 grams (g) ALA per tablespoon
- Chia seeds: 5.06 g ALA per 1-ounce (oz) serving
- Flaxseed: 2.35 g ALA per tablespoon
- Salmon, wild: 1.24 g DHA and 0.59 g EPA per 3-oz serving
- Herring: 0.94 g DHA and 0.77 g EPA per 3-oz serving
- Sardines: 0.74 g DHA and 0.45 g EPA per 3-oz serving
- Oysters: 0.14 g ALA, 0.23 g DHA, and 0.30 g EPA per 3-oz serving
Seafood is the richest source of EPA and DHA. However, other foods like egg yolks and pastured dairy products contain small amounts.
ALA is concentrated in plant foods, such as nuts and seeds, but can also be found in certain oils. Some animal products, like dairy and beef, also provide small amounts of ALA.
How to Take Omega-3 Fatty Acids
Omega-3 fatty acid supplements are usually found in gel-cap form, but they are also available in liquid and gummy form.
Most DHA- and EPA-based supplements are derived from fish or krill. However, there are plant-based DHA and EPA supplements that are appropriate for people following plant-based or vegan diets.
Those who want to take a plant-based omega-3 supplement should consider algal oil-based products. Algal oil contains DHA and EPA, and studies show it's similar in effectiveness to fish-based products in raising levels of these omega-3 fatty acids in the body.
Omega-3 supplements can be taken at any time of day. Some research indicates omega-3s are better absorbed when taken with a meal containing fat, so it may be beneficial to take omega-3 supplements with food.
Taking omega-3 supplements with meals may also help reduce the chances of side effects like nausea and a fishy aftertaste.
Dosage
Dosing recommendations for EPA and DHA vary. Most omega-3 supplements provide 500-1,200 mg of combined EPA and DHA per serving.
People with health conditions like high triglycerides or inflammatory diseases may benefit from higher omega-3 doses exceeding 2 grams per day.
Studies show omega-3 fatty acids at varying dosing can benefit different populations, including pregnant and breastfeeding women, those with inflammatory diseases, and people with heart disease.
It’s important to talk to your healthcare provider if you have questions regarding omega-3 dosing.
Are Omega-3 Fatty Acids Safe?
Omega-3 fatty acids are generally considered safe, but taking them in high doses may not be safe for everyone. The U.S. Food and Drug Administration (FDA) recommends the daily intake of omega-3 fatty acids should not exceed three grams of combined EPA and DHA, with no more than two grams per day coming from supplements.
Unless a higher dose is recommended by a healthcare provider, you shouldn’t take omega-3 supplement doses exceeding two grams per day.
High doses of supplemental EPA and DHA may alter the body’s inflammatory response which could reduce immune function. High doses of EPA and DHA can also inhibit blood clotting, which can cause bleeding issues.
Potential Drug Interactions
Omega-3s have the potential to interact with medications used to thin the blood, which are called anticoagulants. These drugs help prevent blood clotting.
At high doses, omega-3 supplements can also inhibit blood clotting. Because of this, high-dose DHA and EPA supplements may interact with blood-thinning medications, including Warfarin (Coumadin).
What to Look For
When shopping for an omega-3 supplement, it’s important to choose high-quality products from trusted supplement brands.
Whenever possible, purchase omega-3 supplements that have been third-party tested by organizations like ConsumerLab and NSF International, which set strict standards for supplement quality and safety. Many omega-3 supplements, such as fish oil and algal oil, are third-party tested for contaminants such as heavy metals.
It’s also important to choose supplements you can easily tolerate. If you have difficulty swallowing pills, you may want to purchase a liquid or gummy omega-3 supplement.
Can You Take Too Much Omega-3
Unless you have a specific health condition that benefits from high-dose EPA and DHA supplementation, you should not take more than two grams of supplemental EPA and DHA per day.
Taking more than this could increase the risk of side effects, including adverse effects on the immune system and increased bleeding risk.
Side Effects of Omega-3s
Omega-3 supplements are relatively safe, but could cause minor side effects such as:
- A fishy aftertaste
- Odorous breath or sweat
- Heartburn
- Nausea
- Diarrhea
- Stomach cramps
- Headache
Taking high-dose omega-3 supplements could inhibit blood clotting, which may increase bleeding risk. However, taking recommended doses of omega-3s alone should not cause significant bleeding risk.
A Quick Review
Omega-3 fatty acids play important roles in the body, such as regulating inflammation, supporting healthy neurological function, and providing structure to cells.
You can get omega-3 fatty acids from seafood like salmon or sardines as well as seeds like chia and flax. However, many people are deficient in omega-3 fatty acids. Omega-3 supplements, such as fish oil, krill oil, and algal oil, can help support healthy DHA and EPA levels and may benefit those with certain health conditions, such as rheumatoid arthritis and heart disease.
If you’re interested in taking an omega-3 supplement, consider speaking with your healthcare provider to discuss your EPA and DHA needs and appropriate dosing.
