Fatty acids are components of triglycerides, the form in which most dietary lipids are found. Fatty acids are divided into three main classes: saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. Additionally, 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. Therefore, they must be supplied through the diet. Among the essential fatty acids are the omega-3 and omega-6 polyunsaturated fatty acids. 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), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA is considered an essential fatty acid and must be provided 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 the production of hormones that regulate blood clotting and inflammation. (See the collection of Omega 3)
The benefits of omega-3 fatty acids
Studies observe that consuming omega-3 fatty acids may have health benefits, particularly for cardiovascular health. Indeed, omega-3 fatty acids promote a reduction in blood triglycerides, lipids that contribute to the development of heart diseases when present in excess. Some scientific data also suggest that omega-3 fatty acids may help relieve symptoms of rheumatoid arthritis and have a positive effect on mental health (e.g., depression, Alzheimer’s disease), although more studies are needed to confirm these observations.
Dietary 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 plant-based foods such as flaxseed, hemp, chia, soy, and walnuts. (See the Fit-Fit Energy Balls Healthy Snacks 'Grab & Go' 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-linolenic acid, and conjugated linoleic acid. Only LA is essential and must be supplied through the diet. Additionally, like omega-3 fatty acids, omega-6 fatty acids are part of the structure of cell membranes and are involved in the production 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 conducted in ten countries involving a total of 39,740 adults suggest that LA has long-term benefits for the prevention of type 2 diabetes and that AA is not harmful. In 2019, a meta-analysis of 30 prospective studies (68,659 participants) lasting from 2.5 to 31.9 years observed that higher levels of LA and possibly AA were associated with a lower risk of major cardiovascular events.
Dietary 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 certain 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 omega-6 fatty acids, omega-9 fatty acids are not essential because they can be produced by the body.
The benefits of omega-9 fatty acids
In 2021, a systematic review with meta-analysis of 67 trials evaluated the effects of dietary supplementation with olive oil, oleic acid, or hydroxytyrosol, a compound naturally present in olives and olive oil, on metabolic syndrome, a cluster of factors that increase the risk of several chronic diseases. Regarding oleic acid, it had no significant beneficial effect on metabolic syndrome but improved the lipid profile. According to the authors, the results suggest that consuming olive oil or oleic acid is as effective as other strategies for managing metabolic syndrome.
Dietary sources of omega-9 fatty acids
Dietary sources of omega-9 fatty acids include, among others, olive oil, canola oil, and almonds.
References
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- https://www.msdmanuals.com/fr/accueil/sujets-particuliers/compl%C3%A9ments-alimentaires/huile-de-poisson
- https://www.unlockfood.ca/fr/Articles/Sante-du-c%C5%93ur/Acides-gras-omega-3---Oh!-mega-bienfaits!.aspx
- https://www.unlockfood.ca/fr/Articles/Gras/Quelle-est-la-difference-entre-les-acides-gras-ome
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- 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.Circulation, 139(21), 2422–2436. https://doi.org/10.1161/CIRCULATIONAHA.118.038908
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- Whitney, Eleanor N., et al. “The Lipids: Triglycerides, Phospholipids, and Sterols.” Understanding Nutrition, Nelson Education, Toronto, 2013, pp. 128–160.