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Omega-3: The Ultimate Supplement Guide

Written by Tom Von Deck
Reviewed by Lamia A Kader, MD
omega-3 is probably the most popular supplement in the world

In this Ultimate Supplement Guide, we summarize the scientific literature and answer all of the questions about omega-3 that people are asking the most. Find out what are omega-3 fatty acids, what are their health benefits and how much omega-3 you actually need.

There are very few nutrients that medical scientists have studied more than omega-3 essential fatty acids. Even the generations before these studies supplemented with cod liver oil for the numerous health benefits omega-3 provides.

This article contains more than 50 citations from reputable medical websites and scientific studies. We dug through mountains of medical literature so you don’t have to.

If you have any questions, concerns, or even rebuttals, please contact us or leave a comment below. Don’t be a stranger.

What is Omega-3?

sushi & other seafood provide DHA & EPA omega-3

The term omega-3 refers to a group of fatty acids. Three forms of it are considered essential fatty acids. The word “essential” means your body needs them. They are important parts of the membrane of each of your body’s cells. Your body doesn’t make omega-3. You have to get it from foods and/or supplements. (1)

Omega-3 comes in 11 forms. The three normally regarded as the most important forms are considered essential fatty acids. They are called alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA – which is found in plant foods like flax, nuts, and soy – is far less bioavailable than the other two. This means your body will absorb and use a smaller percentage of it by weight. (1)

This does not mean vegetarians or vegans will not get enough omega-3 from plant sources that provide only ALA. They just need more ALA than they would EPA or DHA, both of which come primarily from fish and seafood. The body will turn some ALA into EPA and a smaller amount of it into DHA.

The percentage of ALA your body will absorb may vary a lot, depending on factors such as:

  • Being a young woman of reproductive age (2)
  • Being pregnant
  • Being a young and healthy man (3)
  • Whether you consume large amounts of omega-6 fatty acids (4)

The unused ALA will be stored and/or used for energy like other fats. (5)

To elaborate, high omega-6 intake decreases your ability to convert ALA to the more usable omega-3 forms. So does being a young male instead of a young female. Young men may need to consume twice as much ALA as young women for the same effects.

Keep reading, and you’ll learn what omega-3 fatty acids do for you, the benefits they provide, proper dosages, side effects, and more.

DPA: The “Newest” Omega-3 Fatty Acid

There is a fourth omega-3 compound that scientists have recently begun studying more frequently, and that is docosapentaenoic acid (DPA). Babies typically get equal portions of DPA and DHA – and a smaller portion of EPA – from human breast milk. From fish oils and seafood – the primary sources of DHA and EPA – you will get DPA, too, but far less of it than the others. However, your body absorbs and uses DPA more efficiently than others. (6)

DPA can convert to EPA and DHA in the body.

Like the other omega-3 types, DPA is a polyunsaturated fatty acid (PUFA). It is sometimes considered an “intermediary” essential fatty acid and sometimes just a PUFA. Scientists still argue about whether it should be considered a type of omega-3 at all.

The more DPA is studied in medical science, the more important it is reported to be. New studies tend to reveal new benefits.

How do Omega-3 Essential Fatty Acids Work?

While there is a lot of overlap between DHA, EPA, DPA, and ALA, they all have different functions as well.

  • Your skin, brain, and eye cells have a lot of DHA. (7)
  • EPA may play a bigger role in fighting inflammation than the others because your body uses it to produce anti-inflammatory molecules called eicosanoids. It is also widely recognized for its role in cardiovascular health. (8)
  • DPA is increasingly being recognized for its anti-inflammatory, cognitive, and cardiovascular benefits, but the knowledge base is young.

Omega-3 is involved in so many body processes that you won’t begin to get a clear picture of their numerous jobs until you get to the “What are the Benefits” section below.

Why Does Your Brain Need Omega-3?

omega-3 supplements relieve brain inflammation

A significant percentage of this fat is omega-3 in the form of DHA.

According to animal studies, deficiency in omega-3’s DHA form in developing brains can cause: (9)

  • Problems generating new brain cells
  • Learning disabilities
  • Vision problems
  • Neurotransmitter metabolism issues

Your brain cells contain DPA and EPA. However, the amount of DHA is hundreds of times greater. All of them play a role in brain health. DHA helps keep your brain cell membranes more fluid and elastic and ensures they can signal to other brain cells properly. (10)(11)

What are the Best Omega-3 Food Sources?

walnuts are high in ALA omega-3

List of Plant-Based ALA-Rich Foods

List of Plant-Based ALA-Rich Foods

The top plant sources of ALA are: (12)(13)

  • Flaxseed oil
  • Chia seeds
  • Walnuts

These are the clear winners among plant sources of ALA omega-3.

One U.S. tablespoon, or 14.8mL, of flaxseed oil, can give you 6,700mg to 7,300mg.

An ounce (28.35g) of dried chia seeds provides 5,100mg.

An ounce of walnuts can give you 2,600mg.

Honorable mentions go to hemp seeds, hemp hearts, walnut oil, canola oil, and soybean oil. Be mindful that canola and soybean oils are also high in omega-6 fatty acids. They decrease your body’s absorption of omega-3 because these two groups compete with each other. Safflower and sunflower oils are also high in omega-6.

Plant-Based DHA-Rich & EPA-Rich Foods

If you do a quick internet search on plants that deliver the DHA and EPA forms of omega-3, you may find websites that tout seaweed as a good source. If you look a little closer, you’ll find that 10g of nori seaweed will yield only 10mg-20mg of omega-3. Wakame seaweed will yield the same amount. You will need to eat hundreds of grams of seaweed to meet daily omega-3 requirements. On the bright side, seaweed has far more omega-3 than omega-6. (14)

If you’re a vegetarian looking for direct sources of DHA and/or EPA, your best bet is to go with algae-based (algal) oil. Most algal oil supplements provide DHA and very little EPA. However, some do deliver a lot of both. The human body absorbs the DHA in algal oil fairly easily. (15)

List of Non-Plant DHA-Rich & EPA-Rich Foods

The foods highest in DHA and EPA are seafood like fatty fish and shellfish.

The top non-plant food sources of DHA and EPA are: (16)

  • Salmon
  • Sardines
  • Herring
  • Mackerel
  • Anchovy
  • Cod liver oil
  • Tuna
  • Oysters

100g (3.5oz) of salmon gives you 2,260mg of total omega-3. Herring and anchovy supply a similar amount. Compare that to 1,480mg from sardines. 100g of oysters will yield 435mg of omega-3, roughly a full day’s worth for the average person. Cod liver oil provides almost 2,700mg per tablespoon (14.8mL).

What are the Benefits of Omega-3?

salmon provides essential fatty acids

Omega-3 Relieves Depression Symptoms

In a Norwegian study of nearly 22,000 participants in their 40’s and 70’s found that 2.5% of those who used cod liver oil daily had “High levels of depressive symptoms.” 3.8% of non-users had these symptoms, so they experienced the symptoms at 1.5 times the rate of users. Those who used cod liver oil for longer periods had symptoms at lower rates than those who used it for shorter periods. (17)

In a 2016 analysis of existing randomized placebo studies of people with major depressive disorder, scientists concluded that high-dose (1,000mg-6,000mg) omega-3 supplementation improved symptoms significantly. Omega-3 supplements with antidepressants were even more successful. Omega-3’s EPA form and combinations of EPA and DHA proved to be more successful than DHA alone. (18)

Another analysis of studies singled out EPA as a mood-improver and anti-inflammatory agent in cases of major depressive disorder. They noted that successful supplements were limited to those with EPA levels of at least 60% of total omega-3. Any supplement with a ratio lower than 60/40 EPA/DHA was ineffective at improving depression symptoms. (19)

This is why Ultra Pure Omega-3 by Intelligent Labs is 60/40 EPA/DHA.

Omega-3 Lowers Anxiety

Healthy medical students tested 20% lower for anxiety symptoms than those who took a placebo in a 12-week 2011 study. The omega-3 supplement they took daily was over 2,000mg EPA and 348mg DHA. The best results occurred in those with higher omega-3 to omega-6 ratios in blood samples. (20)

A 2018 analysis of studies demonstrated that omega-3 successfully reduced anxiety in those with and without anxiety-related diagnoses. Researchers noted that the placebo studies bringing significant results used omega-3 doses of 2,000mg or more per day. Those with specific anxiety-related diagnoses received the greatest benefits. There were a total of 1,203 participants in the studies they looked at. (21)

Omega-3 Reduces Severity of ADHD Symptoms

In a 2017 review of 16 controlled studies of children and young people with Attention Deficit Hyperactivity Disorder (ADHD), researchers reported improvements in impulsive behavior, hyperactivity, attention span, reading, visual learning, working memory, and short-term memory. They said supplementation with omega-3 and omega-6, d