Yes, it would be possible to avoid all omega-6 fatty acids in a diet, but it would also leave you stuck with an extremely unhealthy and illness-producing diet. Linoleic acid (LA) is the starting point for production of all omega-6 fatty acids in the body, and our bodies cannot make LA. For this reason, it is well established as an essential fatty acid that cannot be omitted from the diet without dramatic and unwanted health consequences.
In addition to LA, there is a second omega-6 fatty acid that has been shown to have important health benefits, and that fatty acid is gamma-linolenic acid (GLA). GLA clearly belongs in the anti-inflammatory category of fatty acids, and it plays a critical role in our health, particularly with respect to our immune and nervous systems. GLA also appears to be especially important for our health when we are still infants, and we can obtain it through breastfeeding.
In contrast to our clear need for LA as an essential omega-6 fatty acid, and for GLA as an anti-inflammatory omega-6, is our relatively high intake of other omega-6 fatty acids, especially in comparison to our intake of omega-3s. In the average U.S. diet, for example, we are taking in four times as much arachidonic acid (an omega-6 fatty acid designed to help increase inflammation) as EPA (eicosapentaenoic acid, an omega-3 fatty acid designed to help decrease inflammation). We are also taking in twice as much arachidonic acid as DHA (docosahexaenoic acid, another omega-3 that is not only anti-inflammatory but critical for optimal cell membrane and nervous system function).
When I look at the most recent data from the Agricultural Research Service at the U.S. Department of Agriculture (USDA), what I see is an average U.S. diet that is consuming very close to the Dietary Reference Intake (DRI) guideline for LA (the most essential omega-6 fat). The DRI range for the omega-6 fatty acid is approximately 12-17 grams, and the U.S. average intake is approximately 15 grams. Based on this information, I cannot recommend a cutback on our intake of this omega-6 fatty acid. But I also see an average U.S. diet that is extremely lopsided with respect to total fat and total saturated fat intake, and one that seems very low in omega-3s. From my point of view, our best bet in this kind of situation is to keep our intake of LA (the most essential omega-6) fairly steady and to focus instead on reduction of total fat intake and especially saturated fat intake. I also think there is much room for us to improve our omega-6 and omega-3 balance. We could accomplish this task by eating less chicken fat and beef fat and egg yolks (where there is more concentration of the pro-inflammatory omega-6 fatty acid called arachidonic acid) and replacing those foods with wild-caught Pacific salmon, walnuts, flaxseeds, soy foods, and other plants that offer us reasonable amounts of omega-3s.