Find out all about omega-3, including what it does, how much you need, where to find it, and who might need to supplement their diet
Written by Carole Beck on December 6, 2018
Reviewed by Azmina Govindji on December 10, 2018
Overview of omega-3
What is omega-3 and what does it do?
Omega-3 is a type of polyunsaturated fatty acid. We need omega-3 fatty acids for:1
- blood cholesterol
- blood pressure
- children’s growth and development
There are three types of omega-3 fatty acids:
- ALA (alpha-linolenic acid)
- EPA (eicosapentaenoic acid)
- DHA (docosahexaenoic acid)
We have to get all our omega-3 fatty acids from food. Good food sources include nuts and flaxseed oil (ALA) and oily fish, shellfish and marine algae (EPA and DHA).2
You might need to take an omega-3 supplement if you don’t eat fish, are vegetarian or vegan.
What does omega-3 do in the body?
Here’s what each type of omega-3 essential fatty acid does inside the body:3
ALA: needed for children’s normal growth and development, and helps reduce levels of unhealthy LDL cholesterol
DHA: important for a healthy heart, as it helps maintain normal blood pressure, and levels of triglycerides, a type of fat in the blood. It also contributes to normal brain development and vision, and baby’s brain and eye development during pregnancy
EPA: like DHA, it helps maintain normal blood pressure and triglycerides level
ALA is the only type of omega-3 that can’t be made in our body, so we need to make sure we get enough in our diet.
In a pinch, the body can convert ALA into EPA and DHA – though this takes time and doesn’t produce much. So, dietitians advise us to eat foods containing EPA and DHA, like oily fish.4
We need a balance of fats in our diet to stay healthy; an excess of omega-6 fatty acid – another essential fatty acid that our bodies need to source from food – compared to omega-3 can lead to:
Omega-6 is found in vegetable oils, margarine, breads, cakes and biscuits, so it’s best to cut down on processed foods to help reduce your intake, while at the same time upping your intake of omega-3 foods, like oily fish.6
How much omega-3 do I need?
There is no recommendation for omega-3 in UK, though most of us get enough ALA from our food.
However, many people don’t eat enough EPA or DHA, so the UK government advises two portions of fish a week – one of which should be an oily fish7 – or about 450mg of EPA and DHA a day.8
How much omega-3 do children need?
To get enough EPA and DHA, children should eat the following portions of oily fish every week:9
- 18 months-3 years – ¼ – ¾ small fillet
- 4-6 years – ½ to 1 small fillet
- 7-11 years – 1 – 1 ½ small fillets
Which foods are the best sources of omega-3?
The best animal food sources of omega-3 include:
The best plant sources of omega-3:
- ground flaxseeds and flaxseed oil
- rapeseed oil
- nuts – particularly walnuts, almonds, pecans and peanuts
- soy beans and tofu
- algae – this is the only vegetarian source of omega-3 that contains EPA and DHA
- fortified foods, such as eggs enriched with omega-310,11
What are the symptoms of an omega-3 deficiency?
- dry skin, hair and nails
- difficulty concentrating
- stiff joints
What happens if I consume too much omega-3?
Up to 5000mg per day of omega-3 is safe, according to the European Food Safety Authority.13 However, we only need a tenth of this.
If you take more than this, there are risks of:
- excessive bleeding or blood thinning
- impaired regulation of blood glucose levels
- reduced immune function14
When should I take omega-3 supplements?
Most people can get enough omega-3 from their diet, but if you don’t like fish, or are vegetarian or vegan, you might need an omega-3 supplement. Algal oil is the vegan equivalent of fish oil. Eating algae is how fish get their omega-3!
Don’t take fish oil supplements if you are prescribed medication for high blood pressure to avoid any interaction.15
Should children take an omega-3 supplement?
Children should be able to get the omega-3 they need from eating oily fish. However, if they don’t like fish, a supplement may help them reach their daily needs. Read the label to check it’s suitable for children.
Should women take an omega-3 supplement in pregnancy?
You should be able to get all the omega-3 you need from eating a balanced diet, but if you don’t like fish, are vegetarian or vegan, you may benefit from a supplement.
- fish liver supplements, like cod liver oil – it contains high levels of vitamin A, which could be harmful to your unborn baby
- supplements containing more than 450mg of EPA and DHA a day – this has not been proven safe16
What are the benefits of taking an omega-3 supplement?
Historic studies on heart health showed a very positive impact of fish oils on risk of heart attack in ‘at risk’ populations. A 2011 US study reported that 3g or more of omega-3 a day can reduce the levels of fat, such as triglycerides, in your blood,17 while a 2012 report in Advances in Nutrition found that EPA and DHA supplementation can help keep arteries functioning normally.18
Scientists are also examining the role of omega-3 supplements in brain health – in particular with regards to ageing and mood – although more studies need to be done.19
Advice is for information only and should not replace medical care. Please check with your GP before trying any remedies.
1. European Commission. EU Register on nutrition and health claims. Available from: http://ec.europa.eu/food/safety/labelling_nutrition/claims/register/public/?event=register.home
2. Kat Gal. Medical News Today. What are the best sources of omega-3? Available from: https://www.medicalnewstoday.com/articles/323144.php
3. As Source 1
4. British Dietetic Association. Food Fact Sheet: Omega-3. Available from: https://www.bda.uk.com/foodfacts/omega3.pdf
5. Simopoulos AP. An Increase in the Omega-6/Omega-3 Fatty Acid Ratio Increases the Risk for Obesity. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4808858/
6. The European Food Information Council. The importance of omega-3 and omega-6 fatty acids. Available from: https://www.eufic.org/en/food-today/article/the-importance-of-omega-3-and-omega-6-fatty-acids
7. British Nutrition Foundation. n-3 Fatty Acids and Health. Available from: https://www.nutrition.org.uk/attachments/156_n-3%20Fatty%20acids%20and%20health%20summary.pdf
8. Sarah Schenker. Babycentre. Is it safe to take fish oil supplements in pregnancy? Available from: https://www.babycentre.co.uk/x541094/is-it-safe-to-take-fish-oil-supplements-in-pregnancy
9. As Source 4
10. Great Western Hospitals NHS Foundation Trust. Omega 3 Fatty Acids and Heart Health. Available from: https://www.gwh.nhs.uk/media/31921/omega3_fatty_acids_and_heart_health.pdf
11. Freydis Hjalmarsdottir. Healthline. 12 Foods that Are Very High in Omega-3. Available from: https://www.healthline.com/nutrition/12-omega-3-rich-foods
12. Jami Cooley. University Health News. Omega-3 Benefits and Deficiency Symptoms: Why You Need This Essential Fatty Acid. Available from: https://universityhealthnews.com/daily/nutrition/omega-3/
13. European Food Safety Authority. EFSA assesses safety of long-chain omega-3 fatty acids. Available from: https://www.efsa.europa.eu/en/press/news/120727
14. As above
15. NHS Choices. Supplements Who Needs Them? Available from: https://www.nhs.uk/news/2011/05May/Documents/BtH_supplements.pdf
16. As Source 8
17. Shearer GC, Savinova OV, Harris WS. Fish oil – how does it reduce plasma triglycerides? Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3563284/
18. Swanson D, Block R, Mousa SA. Omega-3 Fatty Acids EPA and DHA: Health Benefits Throughout Life. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3262608/
19. Cutuli D. Functional and Structural Benefits Induced by Omega-3 Polyunsaturated Fatty Acids During Aging. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5543674/