Omega-3 in your diet – natural sources and practical advice - Blog

As recently as the early 20th century, fat in the diet was regarded primarily as a source of energy. In 1929, however, it was demonstrated that the complete removal of fat from the diet of animals led to characteristic disorders. In the years that followed, the importance of fatty acids belonging to the omega-3 family, including alpha-linolenic acid (ALA), was confirmed. Currently, the most nutritionally important omega-3 fatty acids include alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the sources of which differ significantly.

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What are omega-3 fatty acids and why are they important?
The best natural sources of omega-3 in the diet
How can you plan meals rich in omega-3?
A comparison of bioavailability: plant-based and animal-based products
FAQ – frequently asked questions

What are omega-3 fatty acids and why are they important?

Omega-3 fatty acids are a type of polyunsaturated fatty acid. The most important ones in the human diet are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). ALA is an essential fatty acid, as the body cannot synthesise it on its own and must obtain it from food. ALA can be converted into EPA and DHA, but this conversion is limited, particularly in the stage leading to DHA. For this reason, sources of ALA and sources of ready-made EPA and DHA are not nutritionally equivalent.

The EFSA has established an adequate intake of ALA for adults at 0.5% of dietary energy, and for the combined total of EPA and DHA at 250 mg per day. EPA and DHA are components of the lipids present in cell membranes, whilst DHA is found in large quantities in, amongst other places, nervous tissue. In the European Union, it is permitted to state that EPA and DHA contribute to the normal functioning of the heart. The beneficial effect is obtained with a daily intake of 250 mg of EPA and DHA. It is also permitted to state that DHA contributes to the maintenance of normal brain function, with the beneficial effect being obtained with a daily intake of 250 mg of DHA.

The best natural sources of omega-3 in the diet

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The richest dietary sources of EPA and DHA are oily sea fish. This group includes, amongst others, salmon, herring, sardines, mackerel and sprats. The EPA and DHA content varies depending on the species, the fish’s diet, the season and the part of the fish, which is why a single portion does not always provide the same amount of these fatty acids. Leaner fish, such as cod, pollock and hake, also contain EPA and DHA, but usually in smaller amounts. Other seafood can supplement these, although the omega-3 content depends on the species.

ALA is the predominant omega-3 fatty acid in plant-based products. Good sources include linseed and linseed oil, chia seeds, walnuts and rapeseed oil. ALA is also found in soya oil, hemp seeds and some green vegetables. Under EU regulations, the claim ‘source of omega-3 fatty acids’ requires at least 0.3 g of ALA per 100 g and 100 kcal of the product, or at least 40 mg of the sum of EPA and DHA per 100 g and 100 kcal.

How can you plan meals rich in omega-3?

Meals rich in omega-3 can be planned so that they regularly include both foods providing EPA and DHA and plant-based sources of ALA. Fish can be the main source of fat in a dish and can be combined with potatoes, groats, wholemeal bread and vegetables. Fish can be baked, stewed, steamed or grilled, without the need to fry it in large amounts of fat.

Ground linseed, chia seeds or walnuts can be added to porridge, yoghurt or a smoothie, whilst rapeseed oil can be used to prepare sauces, salads or for quick frying. In the case of linseed, grinding the seeds makes it easier to utilise the fat they contain compared to swallowing whole, unbroken seeds. Linseed oil is best used cold and stored in accordance with the manufacturer’s instructions, as the polyunsaturated fatty acids it contains are susceptible to oxidation.

How to incorporate omega-3-rich foods into your diet

Product	Easy ways to use
Salmon or mackerel	for dinner with vegetables and groats
Herring or sardines	for sandwiches and salads
Linseed	in porridge, yoghurt or smoothies
Chia seeds	in pudding or porridge
Walnuts	as a snack or salad topping
Linseed oil	in sauces and cold dishes

A comparison of bioavailability: plant-based and animal-based products

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When comparing plant and animal sources, it is important to distinguish between the absorption of fatty acids and their subsequent metabolism in the body. ALA from linseed, chia, nuts or rapeseed oil can be absorbed from the digestive tract, but in order for it to become a source of EPA and DHA, it must undergo a series of enzymatic conversions. In humans, the conversion of ALA to EPA is limited, and to DHA it is usually even lower. The extent of this conversion depends, amongst other things, on gender, the amount of specific fatty acids in the diet and individual metabolism, which is influenced, amongst other factors, by levels of physical and mental activity.

"Omega-3 is not a single component, but several different fatty acids. Plant-based foods, such as linseed, chia seeds and walnuts, primarily provide ALA, whilst oily fish are a source of ready-made EPA and DHA. Therefore, the best approach is a varied diet that regularly includes both plant-based sources of omega-3 and foods providing EPA and DHA.” Łukasz Domeracki – Dietitian

FAQ – frequently asked questions

What are the most important omega-3 fatty acids?

Three are of the greatest importance in the diet: ALA, EPA and DHA. ALA is an essential fatty acid that must be obtained from food. The body can produce EPA and DHA to a certain extent from ALA, but this process is limited.

Which foods are the best sources of EPA and DHA?

The most concentrated natural sources are oily sea fish, including salmon, herring, sardines, mackerel and sprats. EPA and DHA are also found in leaner fish and seafood, usually in smaller quantities.

Where can plant-based omega-3s be found?

Good sources of ALA include linseed and linseed oil, chia seeds, walnuts and rapeseed oil. ALA is also found in, amongst other things, hemp seeds and soya oil.

Can linseed and chia seeds replace fish?

They are not a direct equivalent in terms of the type of omega-3. They mainly provide ALA, which must be converted into EPA and DHA, and this conversion is limited – particularly in the case of DHA.

How much EPA and DHA does an adult need?

According to the EFSA, the recommended daily intake of EPA and DHA combined for adults is 250 mg. With this daily intake of EPA and DHA, the EU-approved health claim regarding their contribution to the normal functioning of the heart may also be used.

Is DHA important for the brain?

DHA is found in large quantities in nervous tissue. In the EU, a health claim is permitted stating that DHA contributes to the maintenance of normal brain function, and the beneficial effect is obtained with a daily intake of 250 mg of DHA.

Is it better to eat linseed whole or ground?

Grinding the seeds makes it easier to utilise the fat they contain. Ground linseed can easily be added to porridge, yoghurt or a smoothie.

Is linseed oil suitable for frying?

In practice, it is best used in cold dishes and stored in accordance with the manufacturer’s instructions. It contains a high amount of polyunsaturated fatty acids that are susceptible to oxidation.

What’s the easiest way to increase the amount of omega-3 in your diet?

It’s worth regularly including oily fish and plant-based sources of ALA. Simple additions to everyday meals include ground linseed, chia seeds, walnuts or rapeseed oil.

Sources:

Baker, E. J., Miles, E. A., Burdge, G. C., Yaqoob, P., & Calder, P. C. (2016). Metabolism and functional effects of plant-derived omega-3 fatty acids in humans. Progress in lipid research, 64, 30–56. https://doi.org/10.1016/j.plipres.2016.07.002
Innes, J. K., & Calder, P. C. (2020). Marine Omega-3 (N-3) Fatty Acids for Cardiovascular Health: An Update for 2020. International journal of molecular sciences, 21(4), 1362. https://doi.org/10.3390/ijms21041362
Dyall S. C. (2015). Long-chain omega-3 fatty acids and the brain: a review of the independent and shared effects of EPA, DPA and DHA. Frontiers in aging neuroscience, 7, 52. https://doi.org/10.3389/fnagi.2015.00052