Démystifions les acides gras oméga-3, 6 et 9

Fatty acids are constituents of triglycerides, the form in which most dietary lipids are found. Fatty acids fall into three main classes: saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. In addition, fatty acids can be essential or non-essential.Essential fatty acids cannot be made by the body and are necessary for its development and functioning. They must therefore be provided by food.. Among the essential fatty acids are the polyunsaturated fatty acids omega-3 and omega-6. As for non-essential fatty acids, they include, among others, omega-9 fatty acids.

Omega-3 fatty acids

The need to consume omega-3 fatty acids

There are three types of omega-3 fatty acids: alpha-linolenic acid (ALA), eicosapentanoic acid (EPA) and docosahexaenoic acid (DHA). ALA is considered an essential fatty acid and must be supplied through the diet. EPA and DHA can be synthesized from ALA. However, this conversion is inefficient. Omega-3 fatty acids are necessary for the development and functioning of the brain, nervous system and retina. They are also an integral part of cell membranes and are involved in making hormones that regulate blood clotting and inflammation. (See the collection ofOmega 3)

The benefits of omega-3 fatty acids

Studies observe that the consumption of omega-3 fatty acids could have health benefits, especially in terms of cardiovascular health. Indeed, omega-3 fatty acids promote a decrease in blood triglycerides, lipids that contribute to the development of heart disease when they are present in excess. Some scientific data also suggests that omega-3 fatty acids may help relieve symptoms of rheumatoid arthritis and have a positive effect on mental health (eg depression, Alzheimer's disease), although more studies are available. necessary to confirm these observations.

Food sources of omega-3 fatty acids

The best dietary sources of EPA and DHA are fatty fish, such as salmon, sardines, trout, and mackerel. As for ALA, it is mainly found in foods of plant origin such as flax, hemp, chia, soy and walnuts. (See theHealthy Snacks Fit-Fit 'Grab & Go' Energy Balls Figs, Walnuts & Chia Seeds)

Omega-6 fatty acids

The need to consume omega-6 fatty acids

There are four types of omega-6 fatty acids: linoleic acid (LA), arachidonic acid (AA), gamma-linoleic acid, and conjugated linoleic acid. Only LA is essential and must be provided by food. Additionally, like omega-3 fatty acids, omega-6 fatty acids are part of the structure of cell membranes and are involved in the manufacture of hormones that play a role in blood clotting and inflammatory responses.

The benefits of omega-6 fatty acids

Data from a 2017 meta-analysis of 20 prospective cohort studies performed in ten countries and involving a total of 39,740 adults suggest that LA has long-term benefits for the prevention of type 2 diabetes and that the 'AA is not harmful. In 2019, a meta-analysis of 30 prospective studies (68,659 participants) ranging in duration from 2.5 to 31.9 years observed that higher levels of AL and possibly AA were associated with risk lower number of major cardiovascular events.

Food sources of omega-6 fatty acids

Dietary sources of LA include vegetable oils (e.g. sunflower, soy, canola), nuts (e.g. walnuts, pistachios) and seeds (e.g. pumpkin, sesame). As for AA, it is mainly found in red meat, poultry, eggs and some fish.

Omega-9 fatty acids

Omega-9 fatty acids generally belong to the family of monounsaturated fatty acids. Oleic acid is an omega-9 fatty acid and the predominant monounsaturated fatty acid in the diet. Unlike omega-3 and 6 fatty acids, omega-9 fatty acids are not essential because they can be made by the body.

The benefits of omega-9 fatty acids

In 2021, a systematic review with meta-analysis of 67 trials assessed the effects of dietary supplementation with olive oil, oleic acid or hydroxytyrosol, a compound naturally present in olive and olive oil. , on the metabolic syndrome, a set of factors that increase the risk of several chronic diseases. At the level of oleic acid, it did not have a significant beneficial effect on the metabolic syndrome, but it did improve the lipid profile. According to the authors, the results suggest that consuming olive oil or oleic acid is as effective as the other strategies for managing metabolic syndrome.

Food sources of omega-9 fatty acids

Food sources of omega-9 fatty acids include, but are not limited to,olive oil, canola oil and almonds.


  1. https://www.merckmanuals.com/professional/special-subjects/dietary-supplements/fish-oil
  2. https://www.msdmanuals.com/en/home/special-topics/food-compl%C3%A9ments/fish-oil
  3. https://www.unlockfood.ca/fr/Articles/Sante-du-c%C5%93ur/Acides-grass-omega-3---Oh!-mega-benefits!.aspx
  4. https://www.unlockfood.ca/en/Articles/Fat/What-is-the-difference-between-fatty-acids-ome
  5. https://www.anses.fr/fr/content/les-lipides
  6. https://extenso.org/article/le-point-sur-les-acides-gras-omega-3/
  7. https://www.anses.fr/fr/content/les-acides-gras-om%C3%A9ga-3
  8. Abdelhamid, A.S., Brown, T.J., Brainard, J.S., Biswas, P., Thorpe, G.C., Moore, H.J., Deane, K.H., Summerbell, C.D., Worthington, H.V., Song, F., & Hooper, L. (2020) . Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease.The Cochrane database of systematic reviews,3(3), CD003177.https://doi.org/10.1002/14651858.CD003177.pub5
  9. https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/types-of-fat/omega-3-fats/
  10. https://extenso.org/documents/files/2014zp-omega-6-versionfinale.pdf
  11. Wu, J., Marklund, M., Imamura, F., Tintle, N., Ardisson Korat, A. V., de Goede, J., Zhou, X., Yang, W. S., de Oliveira Otto, M. C., Kröger, J. , Qureshi, W., Virtanen, J. K., Bassett, J. K., Frazier-Wood, A. C., Lankinen, M., Murphy, R. A., Rajaobelina, K., Del Gobbo, L. C., Forouhi, N. G., Luben, R., Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Fatty Acids and Outcomes Research Consortium (FORCE) (2017). Omega-6 fatty acid biomarkers and incident type 2 diabetes: pooled analysis of individual-level data for 39,740 adults from 20 prospective cohort studies..The lancet. Diabetes & endocrinology,5(12), 965974. https://doi.org/10.1016/S2213-8587(17)30307-8
  12. Marklund, M., Wu, J., Imamura, F., Del Gobbo, L. C., Fretts, A., de Goede, J., Shi, P., Tintle, N., Wennberg, M., Aslibekyan, S. , Chen, T. A., de Oliveira Otto, M. C., Hirakawa, Y., Eriksen, H. H., Kröger, J., Laguzzi, F., Lankinen, M., Murphy, R. A., Prem, K., Samieri, C., Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Fatty Acids and Outcomes Research Consortium (FORCE) (2019). Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality..Traffic,139(21), 24222436. https://doi.org/10.1161/CIRCULATIONAHA.118.038908
  13. Pastor, R., Bouzas, C., & Tur, J.A. (2021). Beneficial effects of dietary supplementation with olive oil, oleic acid, or hydroxytyrosol in metabolic syndrome: Systematic review and meta-analysis.Free radical biology & medicine,172, 372385. https://doi.org/10.1016/j.freeradbiomed.2021.06.017
  14. Whitney, Eleanor N., et al. The Lipids: Triglycerides, Phospholipids, and Sterols.” UnderstandingNutrition, Nelson Education, Toronto, 2013, p. 128160..

Article written by:

Marie-Noël Marsan, Nutritionist


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