Omega-3 fatty acids are essential fats that you must get from the diet.
This is the ultimate beginner's guide to omega-3 fatty acids.
Omega-3 fatty acids are a family of polyunsaturated fats that we must get from the diet. They are also called n-3 or ω-3 fatty acids.
They are termed essential fatty acids because they are needed for health, but the body can not produce them on its own like other fats.
The polyunsaturated part means that the fatty acids have several double bonds in their chemical structure. Omega-6 fatty acids are another type of polyunsaturated fat.
The "omega" naming convention has to do with the placement of the double bond on the fatty acid molecule. Omega-3s have the first double bond placed 3 carbon atoms away from the omega end.
Read this for a more detailed explanation: What Are Omega-3 Fatty Acids? Explained in Human Terms.
Bottom Line: Omega-3 fatty acids are polyunsaturated fats that your body needs, but can not produce on its own. For this reason, they are classified as essential fatty acids.
There are many fatty acids that technically belong to the omega-3 family.
These three are the most important:
1. EPA (Eicosapentaenoic Acid)
EPA is a 20-carbon-long omega-3 fatty acid. It is primarily found in fatty fish, seafood and fish oil.
This fatty acid has many essential functions. Most importantly, it is used to form signalling molecules called eicosanoids. This can lead to reduced inflammation (
EPA has been found to be particularly effective against certain mental conditions, especially depression (
2. DHA (Docosahexaenoic Acid)
DHA is a 22-carbon-long omega-3 fatty acid. It is primarily found in fatty fish, seafood, fish oils and algae.
The main role of DHA is to serve as a structural component in cell membranes, particularly in nerve cells in the brain and eyes. It constitutes about 40% of polyunsaturated fats in the brain (
3. ALA (Alpha-Linolenic Acid)
ALA is an 18-carbon-long omega-3 fatty acid. It is found in high-fat plant foods, especially flax seeds, chia seeds and walnuts.
Despite being the most common omega-3 fat in the diet, ALA is not very active in the body. It needs to be converted into EPA and DHA in order to become active (
Unfortunately, this process is highly inefficient in humans. Only about 5% gets converted into EPA, and as little as 0.5% get converted into DHA (
For this reason, ALA should never be relied on as the sole omega-3 source. Most of the ALA you eat will simply be used for energy.
Bottom Line: There are three main types of omega-3 fats in the diet. EPA and DHA are found in seafood and fish, while ALA is mostly found in high-fat plant foods.
Omega-3 fatty acids are among the most comprehensively studied nutrients on earth.
They have been shown to have powerful health benefits for various body systems.
- Blood triglycerides: Omega-3 supplements can lower blood triglycerides significantly (
14, 15, 16).
- Cancer: Consuming foods high in omega-3 has been linked to a reduced risk of colon, prostate and breast cancer. However, not all studies agree (
17, 18, 19, 20, 21, 22).
- Fatty liver: Taking omega-3 fatty acid supplements can help get rid of excess fat from the liver (
- Depression and anxiety: Taking omega-3 supplements, such as fish oil, can help reduce symptoms of depression and anxiety (
25, 26, 27, 28).
- Inflammation and pain: Omega-3s can reduce inflammation and symptoms of various autoimmune diseases, such as rheumatoid arthritis. They are also very effective at reducing menstrual pain (
29, 30, 31).
- ADHD: In children with ADHD, omega-3 supplements can significantly improve various symptoms (
- Asthma: Omega-3s may help prevent asthma in children and young adults (
- Baby development: DHA taken during pregnancy and breastfeeding can improve the baby's intelligence and eye health (
36, 37, 38).
- Dementia: Some studies link a higher omega-3 intake to a reduced risk of Alzheimer's disease and dementia (
39, 40, 41).
Unfortunately, despite improving several risk factors for heart disease, omega-3 fatty acids have not been shown to prevent heart attacks or strokes. The largest studies that look at the body of evidence find no benefit (
Here is a detailed article about the health benefits of omega-3: 17 Science-Based Benefits of Omega-3 Fatty Acids.
Bottom Line: Omega-3 fatty acids have been studied thoroughly. They have been shown to fight depression, reduce fatty liver, lower blood triglycerides and help prevent asthma, to name a few.
There is no specific recommended daily intake for omega-3 fatty acids.
Mainstream health organizations like the World Health Organization and European Food Safety Authority recommend a minimum of 250-500 mg combined EPA and DHA each day for healthy adults (
The American Heart Association recommends eating fatty fish at least two times per week in order to ensure optimal omega-3 intake for heart disease prevention (48).
If you are trying to improve a specific health condition, then ask your doctor for dosage recommendations.
Read more about the optimal omega-3 intake: How Much Omega-3 Should You Take Per Day?
Bottom Line: It is generally recommended to eat fatty fish at least two times per week, or to take at least 250-500 mg combined EPA and DHA per day from a supplement.
The best way to ensure optimal omega-3 intake is to eat fatty fish at least twice a week.
However, if you don't eat a lot of fatty fish or seafood, then it is probably a good idea to take a supplement.
In fact, most of the studies on the benefits of omega-3 used supplements, so they can definitely be beneficial.
Good supplements with EPA and DHA include fish oil and krill oil. For vegetarians and vegans, taking a DHA supplement made from algae is recommended.
When it comes to omega-3 supplements, there are many choices and not all of them are good. Some supplements may even contain harmful compounds because of pollution in the sea.
Read more here: Omega-3 Supplement Guide: What to Buy, and Why.
Bottom Line: People who do not eat fatty fish or seafood often should consider taking an omega-3 supplement. Fish oil and krill oil are good choices, and DHA from algae is recommended for vegetarians and vegans.
When it comes to nutrition, more is not always better.
As with many other nutrients, there is an upper limit to how much you should take.
According to the FDA, taking up to 2000 mg of combined EPA and DHA per day from supplements is safe.
In high doses, omega-3s can cause blood thinning and excessive bleeding. Speak to your doctor if you have a bleeding disorder or are taking blood thinning medications.
Some omega-3 supplements, especially fish oil, can also cause digestive problems and unpleasant fish oil burps.
Another thing to keep in mind is that many omega-3 supplements are high in calories. Cod liver oil is also very high in vitamin A, which can be harmful in large doses (53).
Make sure to read and follow the dosage instructions.
Bottom Line: Taking up to 2000 mg of omega-3 per day from supplements is safe according to the FDA. Speak to a doctor if you take blood thinning medications or have a bleeding disorder.
Getting plenty of omega-3 fats from whole foods is actually not that hard, at least not if you eat fish.
Here are a few foods that are very high in omega-3:
- Salmon: 4,023 mg per serving (EPA and DHA).
- Cod liver oil: 2,664 mg per serving (EPA and DHA).
- Sardines: 2,205 mg per serving (EPA and DHA).
- Anchovies: 951 mg per serving (EPA and DHA).
- Flax seeds: 2,338 mg per serving (ALA).
- Chia seeds: 4,915 mg per serving (ALA).
- Walnuts: 2,542 mg per serving (ALA).
Several other common plant foods are also high in the omega-3 fatty acid ALA. This includes soybeans, hemp seeds and walnuts. Some vegetables also contain small amounts, including spinach and Brussels sprouts.
Read more: 12 Foods That Are Very High in Omega-3.
Bottom Line: Foods that are very high in EPA and DHA include salmon, cod liver oil, sardines and anchovies. Foods that are high in ALA include flax seeds, chia seeds and walnuts.
Here are quick answers to some common questions that frequently come up about omega-3 fatty acids and fish oils.
1. What is the best form of fish oil?
Most fish oils are in the ethyl ester form.
2. What happens with excess omega-3s in the body?
They will simply be used as a source of calories, like other fats.
3. Can you cook with omega-3 oils?
It is not recommended to cook with them, because they are high in polyunsaturated fats, which can easily damage in high heat.
For this reason, you should also store them in a dark, cool place and not buy in bulk because they can perish.
There is a lot of controversy in nutrition, and it often seems like people can't agree on anything. However, there is almost universal agreement about the importance of omega-3 fatty acids.
They are among the most studied nutrients on the planet, and few things are as well supported by studies as their immense health benefits.
If you don't eat fatty fish or seafood often, then you should seriously consider taking an omega-3 supplement.
It is an incredibly simple but highly effective way to improve both physical and mental health, and may reduce your risk of disease down the line.