More Than a Number: The Difference Between Omega-3, -6, and -9

Fats and particularly mono- and polyunsaturated fatty acids have surged in popularity in recent years as important components of a healthy diet. In particular, omega-3 and omega-6 have been noted for how they benefit the body. But what about omega-9? All of these unsaturated fatty acids are necessary within the body, so what makes them special, and how are they different from one another?

The essentials of essential fatty acids

Alpha linolenic acid (ALA) is an essential omega-3 fat, and linoleic acid (LA) is an essential omega-6 fat; they are “essential” by definition because they cannot be produced in the human body, but rather must be obtained through diet or supplements.1 ALA and LA are basic fats that are important in the daily functioning of bodily tissues.2 However, one must be careful to balance each of these essential fatty acids, because the biological activities of omega-6 can compete with those of omega-3 in the body.3 Furthermore, they share the same enzymes required to produce long-chain polyunsaturated fatty acids like arachidonic acid (AA) from LA and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from ALA.3

Meet omega-3 fats

One of the better-known omega fatty acids, omega-3s are found in both marine and plant sources. While ALA is found in plants (e.g. flaxseeds, chia, walnuts), oily fish like salmon, herring, tuna, and sardines are good sources of EPA and DHA.3 DHA is particularly important for visual and neurological development,3 while EPA is known to support cardiovascular health.4 While a Dietary Reference Intake (DRI) exists for ALA (1.1-1.6 g/day for adults),1 a DRI does not exist (yet) for EPA and DHA. However, the American Heart Association (AHA) encourages seafood consumption, recommending that healthy adults eat a variety of oily fish, at least two servings per week, which nets approximately 500 mg/day of combined EPA and DHA; sadly, over 90% of the US population fails to meet this recommendation.5 Although EPA and DHA can technically be made in the body from ALA, that conversion is very inefficient, so it is prudent to consume EPA and DHA directly3 from seafood and high-quality supplements.

Meet omega-6 fats

The standard American diet is typically rich in omega-6 fatty acids, so meeting the DRI for LA (11-17 g/day for adults)1 is not a challenge. Sources include safflower, sunflower, sesame, soybean, and corn oil, as well as Brazil nuts and pine nuts.3 Evening primrose and borage seed oil are examples of supplements that feature omega-6 fats. According to the AHA, 5% to 15% of daily calories should come from omega-6 fatty acids.6

Last but not least…omega-9 fats

Omega-9 fatty acids (e.g. oleic and mead acids) can be made by the body, but the conversion enzymes required for synthesis prefer omega-3 and omega-6 over omega-9 fatty acids, so synthesis of omega-9 fatty acids only occurs when intake of omega-3 and -6 fats are very low.3 Omega-9 is from a family of monounsaturated fats found in vegetables and animal fats. Often associated with Mediterranean dietary patterns, sources of omega-9 fats include avocados, cashews, almonds, olives, and pecans.7-8

The ohhhh of omega fatty acids

It’s not always easy to get the right amount of each unsaturated fatty acid, but with the advice of your healthcare practitioner, you can be on the road to realizing the many health benefits that each fat provides.

References:

Dietary References Intakes for Energy, Carbohydrate. Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2002/2005).
Essential Fatty Acids. Available at: http://www.pcrm.org/health/health-topics/essential-fatty-acids. Accessed July 5, 2018.
Oregon State University. The Linus Pauling Institute: Micronutrient Information Center. Essential Fatty Acids. http://lpi.oregonstate.edu/mic/other-nutrients/essential-fatty-acids. Accessed July 5, 2018.
EPA (Eicosapentaenoic Acid). https://www.webmd.com/vitamins/ai/ingredientmono-994/epa-eicosapentaenoic-acid. Accessed July 5, 2018.
Richter CK et al. Total long-chain n-3 fatty acid intake and food sources in the United States compared to recommended intakes: NHANES 2003-2008. 2017;52(11):917-927.
Harris W et al. Omega-6 fatty acids and risk for cardiovascular disease: a science advisory from the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing; and Council on Epidemiology and Prevention. Circulation. 2009;119;902-917.
Cooli J. Omega-9 Benefits: Are You Getting Enough? https://universityhealthnews.com/daily/nutrition/omega-9-benefits-are-you-getting-enough. Accessed July 10, 2018.
Finucane O et al. Monounsaturated fatty acid–enriched high-fat diets impede adipose NLRP3 inflammasome–mediated IL-1β secretion and insulin resistance despite obesity. 2015;64(6):2116-2128.