Thromboembolism is the most widespread underlying condition responsible for morbidity and mortality in cardiovascular disease. Haemostasis relies heavily on platelet adhesion, activation and aggregation; however, these processes are also responsible for thrombosis and vessel obstruction at the location of ruptured atherosclerotic lesions which lead to heart attack and stroke.

Polyunsaturated fatty acids (PUFAs) such as omega 3 and omega 6, are essential components of platelet lipid cell membrane and have an essential role in platelet function. Research has shown that dietary PUFAs have been used to reduce inflammation, decrease the progression of cardiovascular disease and prevent acute cardiovascular events. There have also been studies showing the relationship to fish intake and reduced risk of venous thromboembolism.

PUFAs also have an impact on the atherosclerotic process. In blood vessels they improve endothelial function; apply antioxidant, anti-inflammatory, and antithrombotic actions; interrupt the progress of plaques development, improving blood wall stability; and decrease wall stiffening.

These types of essential fats cannot be produced in the body, and must be obtained through the diet. There are three types of Omega 3 – eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are commonly found in fish;  and alpha-linolenic acid (ALA) can be found in vegetable oils and nuts (especially walnuts), flax seeds and flaxseed oil, leafy vegetables, and some animal fat, especially in grassfed animals. However, ALA is seen as primarily being used for energy, and its conversion into EPA and DHA is restricted.

The metabolites (substances made when the body breaks down food, drugs or chemicals) of Omega-6 are mainly proinflammatory/proaggregatory, which can contribute to the risk of cardiovascular events. Therefore, Omega-3 and Omega-6 are intended to balance each other when they are consumed in the diet at a ratio of around 1 to 1.

An increase in Omega-6 fatty acids and alteration in the ratio, could move this balance into a proinflammatory/proaggregatory state, and influence platelet aggregation, coagulation and thrombosis. Omega-6 food sources include corn and peanut oil, soy beans, poultry, eggs, nuts, fast foods, processed snacks, fatty and cured meats. One study found that fish oil lowered platelet aggregation, whereas soy lecithin enhanced platelet reactivity.

For PUFAs to be beneficial for heart health, the quantity is important. The World Health Organization, American Dietetic Association, American Heart Association and many government bodies in Europe, Australia and New Zealand recommend between 140mg to 600g of EPA and DHA daily. The average daily suggestion is 500mg. This equates to roughly 2 servings (30-40g) of oily fish (salmon, tuna, mackerel and sardines) per week. For example, 100g of Tasmanian salmon has approximately 350mg of EPA and 530mg of DHA.

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References

• Adili, R., Hawley, M., & Holinstat, M. (2018). Regulation of platelet function and thrombosis by omega-3 and omega-6 polyunsaturated fatty acids. Prostaglandins & Other Lipid Mediators, 139, 10–18. https://doi.org/10.1016/j.prostaglandins.2018.09.005
• Colussi, G., Catena, C., Novello, M., Bertin, N., & Sechi, L. A. (2017). Impact of omega-3 polyunsaturated fatty acids on vascular function and blood pressure: Relevance for cardiovascular outcomes. Nutrition, Metabolism, and Cardiovascular Diseases, 27(3), 191–200. https://doi.org/10.1016/j.numecd.2016.07.011
• Golanski, J., Szymanska, P., & Rozalski, M. (2021). Effects of omega-3 polyunsaturated fatty acids and their metabolites on haemostasis - Current perspectives in cardiovascular disease. International Journal of Molecular Sciences, 22(5), 2394-. https://doi.org/10.3390/ijms22052394Molendi-Coste, O., Legry, V., & Leclercq, I. A. (2011). Why and How Meet n-3 PUFA Dietary Recommendations? Gastroenterology Research and Practice, 2011(2011), 1–11. https://doi.org/10.1155/2011/364040
• Zhang, Y., Ding, J., Guo, H., Liang, J., & Li, Y. (2020). Associations of fish and omega-3 fatty acids consumption with the risk of venous thromboembolism. A meta-analysis of prospective cohort studies. Frontiers in Nutrition (Lausanne), 7, 614784–614784. https://doi.org/10.3389/fnut.2020.614784
• https://www.tassal.com.au/product/tassal-tasmanian-salmon-portions/
• Dietary fat: Know which to choose - Mayo Clinic