This article is from the Fat-free Diet FAQ, by email@example.com (Michelle Dick) with numerous contributions by others.
Our bodies need a source of both n-6 fatty acids and n-3 fatty
acids (also called "omega-3" fatty acids). n-6 acids can be found
in some meats (arachidonic acid), but are particularly plentiful in
most vegetables (linoleic acid). n-3 acids are plentiful in fish
(eicosapentaenoic acid and decosahexaenoic acid) and in some plant
foods such as flaxseeds, walnuts, wheat, soybeans, oats, corn,
leafy greens and other seeds and nuts (linolenic acid). Actually,
most plant foods contain omega-3 in amounts ranging from 1 to 50%
of total fat.