Omega-3 capsules arranged in the shape of a fish

What is omega-3 made of?

05 Jun 2023

Many of us are already well aware that omega-3s are important for brain functioning, heart health, inflammation, and much more.1

But we often do not know exactly what omega-3s are - or what they are made from.

In short, omega-3s are fatty acids or nutrients found mostly in seafood, but also in greens such as seaweed and algae, as well as in flaxseed oil, chia, and more.

Omega-3 fatty acids explained

Omega-3s are formed in the chloroplasts of grass, leaves, green algae, and other plants.

Humans, animals, and fish cannot produce their own omega-3s. So instead, they get them from this greenery.

For us humans, the best omega-3s that we can get have already been eaten by fish and converted into a type that we can best use for eye, brain, and heart health.2

Omega-3s are a family of polyunsaturated fatty acids. There are actually many types of omega-3s, and their exact chemical composition varies by type.

But it is worth explaining that although fat gets a bit of a bad rap, fatty acids are just a type of carboxylic acid, with a long aliphatic chain.3 Your body needs a certain amount of fat for energy, for protecting organs, and for cell growth.4 Omega-3s, however, are fats that your body does not usually store. Instead, it uses them for brain and eye function.5

Three types of omega-3s

The three types of omega-3s that are most common in your diet and most important for your health are ALA, EPA; and DHA.6

ALA, which stands for alpha-linolenic acid (or α-linolenic acid), is the most common one found in food. Unfortunately, it is also the least useful.

It is still helpful - just not as much as EPA (or eicosapentaenoic acid) and DHA (or docosahexaenoic acid).

ALA is found in flaxseed oil, chia seeds, walnuts, soybeans, and more.

Your body is able to convert a very small percentage of ALA to EPA and DHA. However, it ends up using the rest as it would other fats – for energy or storage.7

EPA and DHA stand for eicosapentaenoic acid and docosahexaenoic acid, respectively.

Though your body uses them differently, both are found in the same foods – mostly oily fishes such as salmon or sardines.

These are the omega-3s that are key structural components of your brain, retina, and other parts of your body.8

Omega-3 supplements and oils

If you cannot, or choose not to eat fish, supplements are one possible alternative when it comes to increasing the amount of omega-3s in your everyday diet.

Microalgae omega-3 supplements

Microalgae contain both EPA and DHA but are not very easy to consume as food.

However, the good news is that you can consume it as a supplement.9

If you are vegetarian but not vegan, it is worth knowing that dairy and eggs from grass-fed animals also contain some EPA and DHA omega-3s.

Algal oil has the highest concentration of EPA and DHA of the various supplement oils. It is also considered to be an environmentally friendly product.10

Flaxseed oil omega-3 supplements

In addition, for people who are allergic to fish (and consequently fish oil), flaxseed oil or ground flaxseed (or related supplements) are often the best options.11

However, they are not the perfect alternative as they only contain ALA omega-3s.

Fish oil supplements

On the other hand, if you are okay with consuming seafood products but cannot find a way to regularly incorporate them into your diet, then cod liver oil is often available as a supplement.

It contains EPA and DHA omega-3s, as well as a significant amount of vitamin D.12

There are other fish oils that people use in supplement form as well, including krill oil and green-lipped mussel oil.

Krill oil is low in contaminants and a potential antioxidant. Its omega-3s are also well absorbed.

Green-lipped mussel oil contains EPA and DHA and trace amounts of ETA – a rare omega-3 that may be even more effective at lowering inflammation.13 People also sometimes use omega-3 supplements to reduce their triglyceride levels and relieve symptoms of rheumatoid arthritis.14

When buying supplements, check that they have EPA and DHA omega-3s, rather than ALA.

And if you use a fish-based omega-3 capsule supplement, be sure to keep an eye on its expiry date.15 Shop Omega-3

Last updated: 4 February 2021


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Donia Hilal

Author: Donia Hilal, Nutritionist

Joined Holland & Barrett: Jan 2018

Bsc in Nutrition, Registered Associate Nutritionist and Certification in Pre and Post Natal Nutrition

Donia started her career as a freelance nutritionist, later she joined Nestle as their Market Nutritionist to help support their healthier product range, before joining the team at Holland & Barrett in January 2018.

Donia has over 6 years experience as a Nutritionist and also works with clients on a one to one basis to support their goals which include weight loss, prenatal and postnatal nutrition and children’s health.