The best food sources of omega-3 and omega-6
Kelsey Brown, BSc
August 31, 2023
Our newest trait release PUFA metabolism and inflammation (FADS1) looks at how we convert polyunsaturated fatty acids (PUFAs) from our diet into omega-3 and omega-6 PUFAs which can impact inflammation, immunity, and brain development. In this article, we’ll provide some deeper insight into what omega-3 and omega-6 are, where we can get these essential nutrients, and their impact on the body.
Polyunsaturated fatty acids (PUFAs)
PUFAs are a group of nutrients that are important for brain development, they regulate the structure and function of neurons (nerve cells that send and receive signals in your brain) and play a role in neuronal survival, helping these cells to survive. PUFAs also play a role in the regulation of inflammatory responses such as brain inflammation and help to regulate the body's immune responses. Due to their role in inflammatory and immune responses, PUFAs can impact an individual’s risk of cardiovascular diseases, diabetes and other diseases linked to chronic inflammation.
Two types of PUFA, which are important nutrients for our health, are omega-6 and omega-3. There are many forms of omega fatty acids, omega-3 fatty acids include alpha-linoleic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA is known as an essential fatty acid, it isn’t produced in our body so needs to be obtained through our diet. The FADS1 enzyme helps to convert ALA from omega-3-rich foods into two other omega-3 fatty acids, EPA and DHA. An essential omega-6 fatty acid is linoleic acid which is obtained through our diet and converted into another omega-6 fatty acid arachidonic acid (AA) by the FADS1 enzyme. Excessively high levels of AA are associated with increased levels of inflammatory markers and a greater risk of coronary artery disease.
Benefits of omega-3 and omega-6 intake
Omega-3 PUFAs such as DHA and EPA are generally known to inhibit inflammation and platelet aggregation (where platelets form together to promote blood clotting) and enhance vasodilation - the widening of arteries and blood vessels to help to promote blood flow, helping to maintain cardiac and vascular function. These PUFAs are seen as a beneficial dietary intervention to help prevent and treat cardiovascular disease.
Omega-6 PUFAs can help to improve cardiovascular health. These PUFAs have an opposing role to omega-3 fatty acids, whereby they help to enhance inflammation, platelet aggregation and vasoconstriction (narrowing of the arteries and blood vessels). High intakes of omega-6 can promote inflammation and, if coupled with low consumption of omega-3 consumption, can lead to poor heart health. There is more evidence to support a more favourable effect of omega-3 than omega-6 on helping to reduce cardiovascular disease risk. Therefore, it is important to get the right proportions of both omega-3 and omega-6 in your diet.
Western diets are known to have excessively high levels of omega-6 due to their content of processed foods and limited intake of oily fish. The recommended ratio of omega-6 to omega-3 is 4:1, whereas in Western diets this ratio can be as high as 25:1. Consuming an excessively high omega-6:omega:3 ratio is thought to contribute to the increasing incidence of inflammatory diseases and cardiovascular diseases.
Sources of omega-3 and omega-6
The Food and Nutrition Board of the Institute of Medicine recommends that an adequate daily intake of omega-3 is 1.6 g for men and 1.1 g for women. The American Heart Association recommends an intake of 5-10% of total energy intake from omega-6 PUFAs: for an intake of 2000 calories, this equates to 11-22 g a day.
Although you can get an adequate amount of omega-3 and omega-6 fatty acids from your diet, there are also supplements available that provide a beneficial amount of omega-3, 6 and 9 PUFAs. Below are some dietary sources of omega-3 and omega-6 PUFAs.
- Fish oil
- Flaxseed oil
- Chia seeds
A 3 oz serving of sardines can have around 2 g of EPA and DHA, so would provide enough omega-3 for the daily adequate amount. The same size serving of herring would provide around 1.5 g of EPA and DHA, so is also a good daily source. 30 g of walnuts contains around 1.8 mg of ALA and a 15 g serving of chia seeds can contain roughly 2.6 g of ALA. Therefore, if eating the right foods (fatty fish, nuts and seeds), it can be easy to get enough omega-3 each day.
- Safflower oil
- Sunflower oil
- Corn oil
- Soybean oil
- Sunflower seeds
- Pumpkin seeds
A tablespoon of sunflower oil contains around 9.3 g of omega-6 fatty acids and a tablespoon of sunflower oil contains 8.9 g. A 30 g serving of walnuts can contain around 10.8 g of omega-6 fatty acids. Eating walnuts can be a good way to get both omega-3 and omega-6 into your system. While good sources of omega-6, be wary of consuming too much of these vegetable oils, as they contain little to no omega-3 and may cause you to consume an unhealthy ratio of omega-6 to omega-3 PUFAs.
Omega-6 can be found in high amounts in fried or processed foods containing corn or soybean oil, so if consuming large amounts of these foods, it is important to balance this out by getting enough omega-3 from fatty fish, seeds and nuts, or limit your intake where possible.
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