A third polyunsaturated fatty acid, alpha-linolenic acid, can be converted into DHA and EPA. While alpha-linolenic acid is available from sources such as canola oil, flaxseed oil, and walnuts, its conversion to DHA is slow and inefficient.23,24 Scientists believe that direct consumption of DHA and EPA is the best way to obtain adequate omega-3 polyunsaturated fatty acids.16,25-32