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Ultimate guide to omega-3s: functions, foods, deficiency and supplements
Written byMedico Digital
Reviewed byJulie Cunningham
Explore our ultimate guide to omega-3: essential fatty acids vital for brain and vision health. Discover top food sources, supplements, recommended intake and their potential benefits
Summary
1What is omega-3?
Omega-3 isn’t just one specific nutrient – it’s the name of a family of fatty acids…
2What do omega-3s do?
They’re best known for their role in supporting heart health, but they’re thought to be important for a number of other things too…
3How can I get omega-3s?
Foods high in omega-3s vary from seafood to seeds…
You’ve likely heard omega-3 is important for your health and that fish is packed with it – but what exactly is omega-3 and why do you need it?
Dive in to discover the best sources of these essential fatty acids, how much you should be getting and the possible benefits it could bring.
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
What is omega-3?
Omega-3 isn’t just one specific nutrient – it’s the name of a family of fatty acids. It refers to a group of polyunsaturated fatty acids that perform important functions in your body.1
Polyunsaturated fatty acids are one of the ‘good’ kinds of fat, known as unsaturated fat.1 They can help lower your levels of ‘bad’ cholesterol, which may have negative effects on your body, like increasing your risk of heart disease and stroke.1,2
There are three main types of omega-3 fatty acids:2,3
- alpha-linolenic acid (ALA)
- eicosapentaenoic acid (EPA)
- docosahexaenoic acid (DHA)
ALA is an essential fatty acid, which means your body can’t make it on its own and you need to get it from the food you eat.1-3 And while your body can make EPA and DHA from ALA, it can only do this in very small amounts, so it’s important to include omega-3 sources in your diet to keep these levels topped up.2,3
Omega-3 benefits: what does omega-3 do in the body?
Omega-3s are best known for their role in supporting heart health – lowering levels of ‘bad’ cholesterol and protecting against heart disease.1-9
They’re thought to be important for a number of other things in the body too, from supporting our vision to contributing to brain health.9-13
Scientists are still studying omega-3s to understand how they affect health and recognise the possible benefits they could bring. Some benefits of omega-3 fatty acids include:1-13
- helping the development of a baby’s nervous system
- supporting prenatal and postnatal brain and visual development
- supporting brain function
- reducing inflammation
- supporting the immune system
- supporting the nervous system
Other areas where omega-3 fatty acids show potential benefits, as suggested by emerging research, include:
- weight management14,15
- inflammation 16
- oxidative stress (cell damage caused by a buildup of harmful molecules)17
However, more research is needed to understand the link between omega-3 and each of these possible benefits.
How much omega-3 do I need?
The NHS recommends that everyone should increase their intake of omega-3s.1 We should all try to eat at least two portions of fish a week, one of which should be an oily fish.1,8
Sources of omega-3
Foods high in omega-3s vary from seafood to seeds – whatever your diet, you can make sure you’re getting all the omega-3s you need.1,4,8
Eating oily fish is one of the easiest ways to get a hearty dose of these powerhouse fats.4,8
Oily fish includes:4,8
- mackerel
- kippers/herring
- trout
- salmon
- sardines/pilchards
- sprats
Some white fish (like sea bass or halibut) can also be a source of omega-3, as can shellfish like crab or squid, though they tend to contain lower levels of omega-3.1,8 Fish are also good sources of other nutrients, including vitamin A and vitamin D, protein, and minerals such as iodine, calcium and selenium.8
However, while oily fish are full of omega-3, they tend to contain higher levels of pollutants than other types of seafood.4 As a result, the NHS recommends that girls and women who are trying to conceive or are pregnant or breastfeeding should eat no more than two portions of oily fish each week.4
If you're not a fan of eating fish, or you're a vegan or vegetarian, there are also plenty of plant-based sources of omega-3 such as:1,5,8
If you’re concerned you’re not getting enough omega-3 through your diet, you can take an omega-3 supplement. These include fish-based oils and plant-based options. Although, you should speak to your GP first so they can recommend what’s best for you.
To find out how to get more of this fatty acid in your diet, check out our guide on the best sources of omega-3.
FAQs
Children should be able to get the omega-3 they need from eating oily fish and following a balanced, healthy diet.8
But if they don’t like fish, you could consider an omega-3 capsule. Kids need less omega-3 than adults, so chat to your GP or a dietitian first for their recommendation.8
If you’re pregnant or trying to conceive, you should avoid supplements which contain vitamin A.8
Fish oil supplements can be high in vitamin A, which can harm your unborn baby if you take too much.4,8 Always check the label first.
Yes, there are plenty of plant-based sources of omega-3.8 As a result, vegans and vegetarians can take a supplement which is made from plant-based sources, such as algae or flaxseed.8
The final say
Omega-3s are a family of essential fatty acids, which means that your body can’t make it by itself and relies on you consuming it. The main types are DHA, ALA and EPA.1,2
There are numerous potential benefits of omega-3s for your body, including their role in improving heart health and reducing inflammation.1,4-8
You should be able to get all the omega-3 you need by consuming two portions of fish per week, one of which should be oily.1 However, you can also take an omega-3 supplement to make sure you’re getting enough.
If you’re considering taking an omega-3 supplement or are concerned about your nutritional needs, you should speak to a healthcare professional, such as your GP or a registered dietician, for tailored advice.
The advice in this article is for information only and should not replace medical care. Please check with your GP or healthcare professional before trying any supplements, treatments or remedies. Food supplements must not be used as a substitute for a varied and balanced diet and a healthy lifestyle.
While we strive for accuracy and balance, please be aware that this article may discuss products available for purchase through Holland & Barrett. Consult a healthcare professional before making any health-related decisions.
- NHS. Facts about fat [Internet]. [cited 2024 Aug 14]. Available from: https://www.nhs.uk/live-well/eat-well/food-types/different-fats-nutrition/
- National Institutes of Health (NIH). Omega-3 fatty acids [Internet]. NIH [reviewed 2022 Jul 18; cited 2024 Aug 14]. Available from: https://ods.od.nih.gov/factsheets/Omega3FattyAcids-Consumer/
- EUFIC. The importance of omega-3 and omega-6 fatty acids [Internet]. [cited 2024 Aug 23]. Available from: https://www.eufic.org/en/whats-in-food/article/the-importance-of-omega-3-and-omega-6-fatty-acids
- NHS. Fish and shellfish [Internet]. [cited 2024 Aug 14]. Available from: https://www.nhs.uk/live-well/eat-well/food-types/fish-and-shellfish-nutrition/
- NHS. Royal United Hospitals Bath. Are you having a nutritionally adequate diet? [Internet]. [cited 2024 Aug 14]. Available from: https://www.ruh.nhs.uk/zz_content_include/services/clinical_depts/dietetics/documents/Are_you_having_a_nutritionally_adequate_intake.pdf
- British Dietetic Association. Fat [Internet]. [cited 2024 Aug 14]. Available from: https://www.bda.uk.com/resource/fat.html
- Djuricic I, Calder PC. Beneficial outcomes of omega-6 and omega-3 polyunsaturated fatty acids on human health: An update for 2021. Nutrients. 2021;13(7):2421. https://doi.org/10.3390/nu13072421
- British Dietetic Association. Omega-3 [Internet]. [cited 2024 Aug 14]. Available from: https://www.bda.uk.com/resource/omega-3.html
- National Institutes of Health. Office of Dietary Supplements - Omega-3 fatty acids [Internet]. [cited 2024 Aug 14]. Available from: https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/#h7
- Lange KW. Omega-3 fatty acids and mental health. Global Health J. 2020;4(1):18–30. https://doi.org/10.1016/j.glohj.2020.01.004
- NHS. The links between diet and behaviour: The influence of nutrition on mental health [Internet]. [cited 2024 Aug 14]. Available from: https://www.oxfordhealth.nhs.uk/cotswoldhouse/wp-content/uploads/sites/7/2013/04/The-links-between-nutrition-and-mental-health.pdf
- van der Wurff ISM, et al. Effect of omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFA) supplementation on cognition in children and adolescents: A systematic literature review with a focus on n-3 LCPUFA blood values and dose of DHA and EPA. Nutrients. 2020;12(10):3115. https://doi.org/10.3390/nu12103115
- Alzheimer’s Society. Diet and dementia [Internet]. Alzheimer’s Society [reviewed 2023 Dec; cited 2024 Oct 1]. Available from: https://www.alzheimers.org.uk/about-dementia/managing-the-risk-of-dementia/additional-treatments-for-dementia-risk/diet
- Onakpoya IJ, Posadzki PP, Watson LK, Davies LA, Ernst E. The efficacy of long-term conjugated linoleic acid (CLA) supplementation on body composition in overweight and obese individuals: a systematic review and meta-analysis of randomized clinical trials. European Journal of Nutrition [Internet]. 2011 Oct 12 [cited 2024 Nov 13]; 51: 127-134. Available from: https://link.springer.com/article/10.1007/s00394-011-0253-9
- Namazi N, Irandoost P, Larijani B, Azadbakht L. The effects of supplementation with conjugated linoleic acid on anthropometric indices and body composition in overweight and obese subjects: A systematic review and meta-analysis. Crit Rev Food Sci Nutr [Internet]. 2019 Jan 22 [cited 2024 Nov 13]; 59(17): 2720-33. Available from: https://pubmed.ncbi.nlm.nih.gov/29672124/
- Kavyani Z et al. Efficacy of the omega-3 fatty acids supplementation on inflammatory biomarkers: An umbrella meta-analysis. Int Immunopharmacol [Internet]. 2022 Jul 30 [cited 2024 Nov 13]. Available from: https://pubmed.ncbi.nlm.nih.gov/35914448
- Heshmati J et al. Omega-3 fatty acids supplementation and oxidative stress parameters: A systematic review and meta-analysis of clinical trials. Pharmacol Res [Internet]. 2019 Sep 26 [cited 2024 Nov 13]. Available from: https://pubmed.ncbi.nlm.nih.gov/31563611/
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