Omega 3 – What’s it all about?

Omega 3

Omega-3 has been a pretty hot topic in the media for the last few years and it’s also super relevant at the moment as a lot of attention has also been given to plant-based diets too.

I’ve previously written about other nutrients that are relevant for maternal and infant nutrition such as: Calcium, iron, iodine and vitamin D. Now is the turn of this very complex and little understood nutrient – Omega-3!

What is omega 3?

Omega-3 Fatty Acids are a family of PUFAS (polyunsaturated fatty acids) classified by their chemical structure; ‘poly’ meaning many and ‘unsaturated’ meaning double bonds.

There are different forms of omega-3 fats, and these are:

  1. ALA
  2. EPA
  3. DHA

ALA (alpha-linolenic acid): this cannot be made in the body and therefore we use the term ‘essential’ to describe this fatty acid, meaning it is important we take this in via our diet.

EPA (eicosapentaenoic acid): this is made from ALA in our bodies and these are long-chain fatty acids which help to produce chemicals called eicosanoids. These chemicals can help reduce inflammation.

DHA (docosahexaenoic acid): this is also made from ALA in our bodies and is important for keeping our brain development and function in tip top condition.

The conversion of EPA and DHA from ALA happens slowly and only in relatively small amounts – so it is thought to be important that we also consume plenty of EPA and DHA directly from our diet.

The current average intake in adults is 1% in men and 1.1% in women (British Nutrition Foundation., 2019). Recommendations are that as a minimum we should have 0.2% of our food energy coming from Omega-3s.

Health benefits

There are a whole range of potential benefits that Omega-3 can offer us that include heart health, mental health and infant development.

Omega-3 may help to prevent irregular heartbeats and improve the cholesterol balance of blood by increasing levels of the good cholesterol (HDL).

There is also emerging research that suggests that omega-3 may help mild to major depression – to read more about this check out this NHS summary of a systematic review on the topic!

Omega-3s for mum and baby

Before baby has even arrived, incorporating fish into your diet during pregnancy appears to be beneficial for baby’s development, however it’s important to remember that this may also be due to the other nutrients found in fish such as:

  • Selenium
  • Iodine

…which are also really good for baby’s brain too!

DHA concentrations are involved in visual and neural function and, in fact, during the last trimester baby accrues about 50mg to 70mg a day! Therefore DHA is really important for mum to get in order to help baby’s brain development.

After baby has arrived and as baby grows up, omega-3s make a great addition to any healthy diet and may even be protective in maintaining good memory and prevention and treatment of depression! (BDA)

Where does Omega-3 come from in our diets?

Oily fish are the richest source of omega-3 and these can be found in foods such as:

  • Herring
  • Kippers
  • Mackerel
  • Pilchards
  • Sardines
  • Trout

Canned fish can be a good source of omega-3s and tend to be a lot more convenient and cheaper but please do check the label – the British Heart Foundation endorses the Princes brand of tinned fish as it has a higher omega-3 content so it might be worth looking out for this on your next food shop!

White fish and shellfish also contain good amounts:

  • Sea bass
  • Sea bream
  • Mussels
  • Oysters
  • Squid
  • Crab

Omega 3I don’t like fish – how do I get my omega-3?

There are small amounts of omega-3 in a range of other foods such as:

  • Dark green leafy vegetables (spinach and kale)
  • Soya beans and tofu
  • Nuts (walnuts, pecans, peanuts and almonds)
  • Linseeds, rapeseed, canola and flaxseed oil

These foods are a source of ALA. This is the family of omega-3 fats that cannot be made in the body so must be consumed in out diet.

These foods still make up a great part of any healthy, balanced diet but it is important to keep in mind that they do not contain the same omega-3 fats that you will get from fish (EPA/DHA)

If you do not like/eat fish, it may be worth considering supplementation but please do consult your GP first.

Some foods have been fortified with omega-3 and these can be incredibly useful sources if you are someone who avoids fish. These included eggs and certain milks as well as yoghurt and bread – to check this, have a look at the packaging when you’re next at the supermarket.

Omega-3 supplements:

Being vegan will restrict the variety of food in which you can get your DHA and EPA requirements. However, most DHA and EPA supplements are derived from algae and so will be suitable options for vegans or those avoiding fish. Research on the bioavailability of this IS limited, however it is indeed an original source of DHA and EPA – interestingly, the reason for the high quantities of these fatty acids in fish is because they consumed the algae in the first place!!

Recommended amounts

In the UK, the Government recommends that we have 2 portions of fish a week – one of which should be oily as part of a balanced diet (one portion equates to around 140g when cooked) – this is the same as America, however Australia recommendations are between 2 and 3 portions a week.

Although we do not have specific recommendations for the amount of omega-3s we should be consuming, research suggests that consumption of 2 portions of fish a week would have significant public health benefits across the UK (such as reducing cardiovascular disease).

This recommendation should also apply to pregnant and lactating women, subject to the restrictions on certain fish (which include marlin, swordfish, shark and tuna) – this is because there is a risk that the pollutants (specifically mercury) may build up in the body, negatively effecting on the development of a foetus.

However, for the majority of the population, the health benefits of eating oily fish regularly far outweigh the potential risks of the build-up of pollutants!

I’ve also written previously about fish recommendations for babies and toddlers here, which includes a table with the recommendations laid out clearly.

Below is a guideline demonstrating the portion amounts for baby from 18 months onwards from the British Dietetic Association.

It is recommended that children under the age of 16 avoid eating shark, swordfish or marlin because of the levels of mercury found in these fish, which may damage the child’s nervous system.

TOP TIP: when food shopping, pick up fish last and take is straight home!


Fish stocks are rapidly depleting (such as wild salmon and trout) and most of us should try and ensure that the fish we buy comes from sustainable sources.

When choosing your fish at the supermarket, look out for the marine stewardship council (MSC) certified products. You can also search for the good fish guide from the Marine Conservation Society (they also have an app!) – here’s the link:


Currently in the UK there are no recommendations for omega-3 supplements. However, if you do choose to take supplements it is important to remember the following (via British Dietetic Association):

  1. Look for omega-3 oil rather than fish liver oil
  2. Check the vitamin A content (do not take supplements containing vitamin A if you are pregnant or planning a baby – more on this in a bit!)
  3. Choose an age-appropriate supplement (children will need less than adults)
  4. Seek advice from a Nutritionist/Dietitian or your GP if you are concerned

It is also important to look for accreditation badges as the BBC suggests that brands that have sought accreditation are more likely to have good quality control in place.

Fish store their vitamin A in their livers so if you are pregnant or planning a baby, supplements containing vitamin A such as fish liver oil supplements, high-dose multivitamin supplements or any supplements containing vitamin A (sometimes written as retinol) must be avoided – too much vitamin A can harm the unborn baby.

SACN advises that pregnant women should not have more than 1.5mg of vitamin A per day (from food and supplements combined)

More information:

Article written by Holly Roper MSc student University of Sheffield with support from SR Nutrition.

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