Essential fatty acids (EFA) are are collections of lipids that are not able to be synthesized by the human body -- they must be consumed. The development of consumption of EFAs throughout human evoultuionary history is thought to have had a significant impact on the development of human intelligence and the establishment of culture, language and symbolic representation (Arts, Ackman, & Holub, 2001).
Arts, M.T., Jackman, R.G., and Holub, B.J. (2001). "Essential Fatty Acids" in aquatic ecosystems: a crucial link between diet and human health and evolution. Canadian Journal of Fisheries and Aquatic Sciences, 58: 122-137.