There are three kinds of polyunsaturated fatty acids (PUFA): omega-3, -6 and -9. Omega-3 and -6 are termed essential fatty acids because the body cannot synthesise them, and they must therefore be acquired through dietary consumption. (The body can make its own omega-9.)
PUFAs regulate a wide variety of biological functions, ranging from blood pressure and blood clotting to the optimal development and functioning of the brain, eye and nervous system. In addition, the metabolic end-products – arachidonic acid in the omega-6 series, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the omega-3 series – play essential roles in regulating the immune and inflammatory responses.
The ratio today
Over the past few decades, in the typical Western diet, the consumption of omega-6 fatty acids has increased and omega-3 decreased. In earlier times the ratio was 1:1, but nowadays it often is 15–20:1 or even higher.
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This high ratio of omega-6 fatty acids is not desirable, as too much of it can contribute to pro-thrombotic processes such as clotting and also because they are pro-inflammatory. Because inflammation plays an important role in the development of chronic diseases, too much omega-6 plays a role in the predisposition toward, as well as the exacerbation of conditions such as obesity, diabetes, metabolic syndrome, cardiovascular diseases, arthritis, Alzheimer’s, depression and many types of cancer.
Therefore, decreasing the ratio of omega-6 to omega-3 brings about a lower incidence of these chronic inflammatory diseases. The optimal recommended omega-6 to omega-3 ratio is 1–4:1.
How does one achieve the optimal ratio?
Decreasing our omega-6 intake and increasing our consumption of omega-3 fatty acids can be accomplished by:
1. Replacing dietary vegetable oils high in omega-6 fatty acids (e.g. corn, sunflower, safflower, and cottonseed oils, shortening, margarine) with oils high in omega-3 fatty acids (flax, chia, hemp, rapeseed/canola).
2. Increasing our consumption of fatty fish to 2–3 times per week, can help us to decrease our consumption of red meat (esp. grain-fed beef and lamb), which is high in omega 6 fatty acids.
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Practical tips for consuming more omega-3 fatty acids and less omega 6 fatty acids:
- Eating at least two 120g servings of seafood or fatty fish such as salmon, pilchards, sardines, mackerel, trout or fresh tuna per week reduces the risk of disease. With wild caught fish, e.g. salmon, being the best option. Be cautious however, when consuming king mackerel due to its high mercury content. Omega-3 fatty acids are however not limited to fish, they are also found in walnuts and vegetable oils like chia, flax and hemp seeds.
- Replace sunflower oil with vegetable oils such as canola oil, flaxseed oil, walnut oil and olive oil.
- Add walnuts, chia seeds (soaked) or ground flaxseed to cereals, smoothies, yogurt and salads.
- Choose enriched or pastured omega 3 eggs and grass-fed meat products.
- Substitute ground flaxseeds for butter or oils when baking. You can substitute 1 tablespoon of oil with 3 tablespoons of ground flaxseed.
- Limit products manufactured with oils containing omega 6 fatty acids such as mayonnaise and salad dressings, and try to avoid processed foods such as crisps, take away foods, deep fried foods (onion rings, chips, chicken nuggets or pieces) and baked goods such as biscuits, cupcakes, or crackers etc.
- If you consume substantial amounts of conventional meat products and/or don’t eat sufficient fatty fish, consider taking a fish oil supplement.
As omega-3 helps to combat chronic inflammatory diseases, the American Heart Association recommends an intake of 500 to 1,000 mg of DHA and EPA per day, preferably from eating foods like fatty fish at least twice a week. They also recommend the regular intake of omega-3-rich plant sources, such as flaxseed, chia seeds and walnuts.
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1. Calder, PC. 2012. Mechanisms of Action of (n-3) Fatty Acids. The Journal of Nutrition, 142: 592S–599S
2. Patterson, E., Wall, R., Fitzgerald, GF., Ross, RP and Stanton C. 2012. Health Implications of High Dietary Omega-6 Polyunsaturated Fatty Acids. Journal of Nutrition and Metabolism. Volume 2012, Article ID 539426, 16 pages
3. Simopoulos, AP. 2016. An Increase in the Omega-6/Omega-3 Fatty Acid Ratio Increases the Risk for Obesity. Nutrients, 8, 128
4. De Lorgeril M and Salen P. 2012. New insights into the health effects of dietary saturated and omega-6 and omega-3 polyunsaturated fatty acids. BMC Medicine, 10:50