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.^8,9 A controlled study showed that a low arachidonic acid diet provided some relief to people with rheumatoid arthritis, an inflammatory disease.¹⁰ 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.¹¹ 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.^12,13 However, production of arachidonic acid from other omega-6 fatty acids appears to be quite limited.¹⁴ Also, gamma-linolenic acid is an omega-6 fatty acid that the body can use to make anti-inflammatory substances.^15,16 Finally, preliminary studies have found that blood measures of inflammation are actually lower in people with higher omega-6 intake,^17,18 and preliminary and controlled studies suggest that high omega-6 intake prevents cardiovascular disease.¹¹ Overall, there appears to be benefit, not risk, in consuming omega-6 fatty acids other than arachidonic acid.