According to my copy of "Prescription for Nutritional Healing" Omega 3 has "alpha-linoleic and eicosapentaenoic acid" and "are found in fresh deepwater fish" etc.
Omega 6 has linolenic and gamma-linolenic acids and found primarily in nuts etc.
The book didn't say anything about Omega 9, but I'm sure it's important.
I'm taking Flaxseed Oil and it's apparently a good source for B vitamins, proteins, zinc, magnesium, potassium and fiber.
Any herb shop will probably have fish oil or flaxseed oil supplements and can tell you more about them.
