Do Omega-6 Fatty Acids Cause Inflammation?
Short answer: No, not in the simplistic way you read about online. Omega-6 fatty acids are essential to health. We do tend to get a lot of them in our diet and often too little omega-3 fatty acids.
Longer answer: It’s a little more complicated than yes/no. Let’s look at it in more detail. Arachidonic acid (AA) is a longer chain fatty acid made from the parent omega-6 fatty acid, Linoleic acid (LA). AA is usually the one blamed as being inflammatory. And it’s true; it is used to create inflammatory compounds (like prostaglandin E2, thromboxane A2). It is also used to make anti-inflammatory molecules (like prostacyclin, lipoxin) though.In addition, other long chain fatty acids in the omega-6 family made from LA are Gamma-Linolenic Acid (GLA) and Dihomo-γ-linolenic acid (DGLA). These are used to make molecules with anti-inflammatory effects and DGLA even inhibits AA from being used to make inflammatory molecules. In addition, production from LA to AA is tightly regulated so increasing LA in the diet will generally not lead to increased AA. Conversion is about 0.2% by weight.
And finally, the body uses the same enzyme (delta-5 desaturase) to produce both the omega-3 Eicosapentaenoic acid (EPA) and the omega-6 Arachidonic acid (AA). If there’s not enough omega-3 in the diet and/or with certain health issues (like type 2 diabetes), more AA will be produced than EPA. With enough omega-3 in the diet, EPA production tends to keep excess AA production and excess inflammation in check.AA is a structurally important fatty acid in the brain—just as important as Docosahexaenoic acid (DHA) from the omega-3 family. Both are key ingredients in breast milk for a reason—growing brains need them. AA has also been found helpful for strength training; it enhanced anaerobic capacity and lessened the inflammatory response to training in some studies. Finally, other studies have found that AA consumption improved upper body strength, lean body mass, and peak power during strength and resistance based training. When does it lead to inflammation? First, if lipid peroxidation (fats in the body being damaged by free radicals) is occurring. Second, if people are dealing with joint pain and inflammatory conditions and are already more metabolically prone to producing inflammatory compounds and not getting enough omega-3 is in the diet. It’s also important to distinguish between acute inflammation—a normal part of the immune response in which omega-6 fatty acids play an important role as substrate for making inflammatory molecules—and chronic inflammation that sets in with chronic disease states and is not the normal, beneficial type of short-term inflammation. http://circ.ahajournals.org/content/119/6/902.full https://www.ncbi.nlm.nih.gov/pubmed/18045476 https://www.ncbi.nlm.nih.gov/pubmed/27182886 http://www.ncbi.nlm.nih.gov/pubmed/25173718