Omega-3 fatty acids are a type of unsaturated fat that you can only get from your diet. They’re important for brain development, cell structure and producing hormones. They also reduce inflammation in your body and might protect you from chronic diseases, like heart disease. Oily fish is usually the best source of omega-3 fats. It’s also important to get the right omega-6 to omega-3 ratio.

What are omega-3 fatty acids?

Omega-3 fatty acids are a type of essential unsaturated fat that you must get from food or supplements.

The three most important types of omega-3s are:

  • Docosahexaenoic acid (DHA): This is the most important omega-3 fat in your body. It makes up an important part of your brain and eyes. This is mostly found in animal products, like oily fish. You can also get some DHA from grass-fed meat, eggs and dairy.
  • Eicosapentaenoic acid (EPA): This is mostly found in animal products, like oily fish.
  • Alpha-linoleic acid (ALA): This is the most common omega-3 fat in food. Your body needs to convert this into EPA and DHA before it can use it. ALA is found in things like flaxseed, chia seeds, walnuts and hemp seeds.

Benefits of omega-3 fatty acids

Omega-3s are essential for your health. They make up a really important part of the structure of each cell in your body and help you to produce hormones. Omega-3s are also really important for brain growth and development in babies.

Eating high amounts of omega-3s is also linked to a whole range of other health benefits. This is mainly because they can help reduce long-term, low levels of inflammation (chronic inflammation).

Heart health
The anti-inflammatory benefits of omega-3s can stop your heart and blood vessels from getting damaged. They might also lower your blood lipids (triglycerides), blood pressure and risk of blood clotting. This can 
reduce your risk of things like heart attack, stroke and sudden cardiac death.

Arthritis
Omega-3 fats might help ease arthritis symptoms by reducing the inflammation and pain in your joints. They’re also linked to improved bone and joint health, which might help protect you against arthritis and osteoporosis.

Cancer
A diet high in omega-3s is linked to a lower risk of some cancers, particularly colon cancer.

Mental health
A diet high in omega-3s, particularly EPA, might help treat or protect you against depression and anxiety.

Sleep
A diet high in omega-3s, particularly DHA, might help you have longer, better quality sleep. This is probably because omega-3s are linked to the sleep hormone, melatonin, which helps you fall asleep.

Obesity
A diet high in omega-3 fats might increase your metabolism and aid weight loss. Omega-3s might also improve gut health which is thought to offer some protection against obesity.

Getting omega-3s from your diet

Oily fish, like salmon, trout, mackerel, tuna and sardines, is one of the best sources of omega-3s. It’s recommended that you aim to eat two portions a week. Although not as rich in omega-3s, other animal sources include grass-fed meat and omega-3 enriched eggs.

There are some plant sources of omega-3, like flaxseeds, chia seeds, walnuts and hemp seeds. But your body finds it harder to use this type of omega-3 (ALA). If you’re vegan, vegetarian or don’t eat a lot of fish you might need to think about taking a supplement.

Getting omega-3s from supplements

There’s lots of omega-3 supplements to choose from but some are better than others. Natural fish oil, krill oil, mammalian oil, green-lipped mussel oil and algal oil (vegan) are all good omega-3 supplement options.

You should also make sure the supplements contain both EPA and DHA and see how much EPA and DHA is actually in it — natural fish oils usually contain about 30% EPA and DHA which is enough for most people.

Another thing to look out for is the form of omega-3 in the supplement. Your body finds it easier to absorb omega-3s in the form of free fatty acids, although this is mostly found in foods. So the next best form is triglycerides and phospholipids. Try to avoid ones that come in the form of ethyl esters as these are harder for your body to absorb.

Read more in our article on omega-3 supplements.

Your Omega-6 to Omega-3 ratio

As well as including lots of omega-3 rich foods in your diet, you also have to make sure you’re not eating too much omega-6 fats. While omega-3s reduce inflammation in your body, omega-6s promote it. Omega-6s are still essential for your health — for example, inflammation helps your body fight infections. But too much inflammation can put you at risk of things like heart disease, cancer, arthritis and diabetes.

It’s important to have balanced amounts of omega-6s and omega-3s — this is measured by looking at your omega-6 to omega-3 ratio. Ideally, this ratio should be 2:1. But most Western diets are way too high in omega-6 so the ratio is around 10:1, or even higher in some cases.

To lower the amount of omega-6 fats in your diet avoid processed vegetable oils. These include vegetable oil, corn oil, safflower oil, soybean oil, and cottonseed oil. You should also avoid processed foods that contain these.

How to test your omega-3 and omega-6 fatty acids

You can check the level of omega-3 and omega-6 fats in your body with a simple finger-prick blood test. This will also tell you your omega-6 to omega-3 ratio. From this, you can get an idea of the level of inflammation in your body and your risk of heart disease.

References:

Berger, M. E., Smesny, S., Kim, S. W., Davey, C. G., Rice, S., Sarnyai, Z., … & Amminger, G. P. (2017). Omega-6 to omega-3 polyunsaturated fatty acid ratio and subsequent mood disorders in young people with at-risk mental states: a 7-year longitudinal study. Translational psychiatry, 7(8), e1220.

Krishnadas, R., & Cavanagh, J. (2012). Depression: an inflammatory illness?. J Neurol Neurosurg Psychiatry, jnnp-2011.

Riediger, N. D., Othman, R. A., Suh, M., & Moghadasian, M. H. (2009). A systemic review of the roles of n-3 fatty acids in health and disease. Journal of the American Dietetic Association, 109(4), 668-679.

Simopoulos, A. P. (2016). An increase in the omega-6/omega-3 fatty acid ratio increases the risk for obesity. Nutrients, 8(3), 128.

Simopoulos, A. P. (2002). The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomedicine & pharmacotherapy, 56(8), 365-379.

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