One of the omega-6 fatty acids, arachidonic acid, can be used by the body to make substances that are inflammatory, increase blood clotting, or constrict blood vessels.^{16, 17} A controlled study showed that a low arachidonic acid diet provided some relief to people with rheumatoid arthritis, an inflammatory disease.¹⁸ However, studies of the effect of arachidonic acid on heart disease risk factors have found either no effect or a beneficial effect of higher arachidonic acid intake.¹⁹ More research is needed to determine the effects of arachidonic acid on different diseases.

Since arachidonic acid can be made from other omega-6 fatty acids, some authorities have theorized that reducing the consumption of all omega-6 fatty acids might help prevent or relieve inflammatory diseases and other conditions, such as heart disease, that are associated with certain arachidonic acid byproducts.^{20, 21} However, production of arachidonic acid from other omega-6 fatty acids appears to be quite limited.²²Also, gamma-linolenic acid is an omega-6 fatty acid that the body can use to make anti-inflammatory substances.^{23, 24} Finally, preliminary studies have found that blood measures of inflammation are actually lower in people with higher omega-6 intake,^{25, 26} and preliminary and controlled studies suggest that high omega-6 intake prevents cardiovascular disease.²⁷ Overall, there appears to be benefit, not risk, in consuming omega-6 fatty acids other than arachidonic acid.