Omega-6 fatty acids are a type of polyunsaturated fatty acid not produced by the body.
Diets in which polyunsaturated fatty acids replace saturated fats have been seen to lower negative coronary events. However, animal studies suggest that compared to Omega-3s and saturated fats, Omega-6 promotes inflammation and possibly tumor growth. Research suggests that it is the intake of Omega-6 relative to Omega-3 that is most important in predicting its negative health effects, with greater Omega-3 intake being optimal. In studies where solely Omega-6-rich oil was supplemented, with no Omega-3s to balance, more coronary events were seen compared to controls.
Omega-3 supplements can lose their benefits when the diet is still rich in Omega-6. Recommended Omega-6 to Omega-3 ratios vary between 1:1 (National Insitutes of Health) to 4:1 (Japanese government) to 10:1 (United States National Academy of Science.) Estimates of average intake ratio by typical Americans is between 14 and 25 times more Omega-6 than Omega-3s.
Vegetable oils, notably: sunflower, corn, soybean, cottonseed. Foods containing these oils. Peanut oil, sesame oil. Soybeans and soy products, peanuts, sunflower seeds, sesame seeds.
Advances in Nutrition
University of Maryland Medical Center
The American Journal of Clinical Nutrition