DHA (docosahexaenoic acid) is an omega-3 long-chain polyunsaturated fatty acid (LCPUFA). ARA (arachidonic acid) is an omega-6 long-chain polyunsaturated fatty acid (LCPUFA). Both are non-essential fatty acids because the human body has the capability of making them from other available fats already consumed. DHA is made from linolenic fatty acid and ARA is made from linoleic fatty acid. Linolenic and linoleic fatty acids are essential fatty acids meaning that the body cannot make them and they must be provided through the foods we eat.
Food sources of DHA include cold water fish and their oils, egg yolks, and organ meats such as liver. ARA is found mostly in animal products, such as eggs, meat and some fish such as tilapia and catfish.