The protein found in flaxseed is very similar to that of soybean protein, which is considered one of the most nutritious plant proteins. This is due to the type of amino acids present, the building blocks of protein. Flaxseed contains numerous 'essential amino acids', which the body cannot produce and therefore must obtain from the diet.
~ Kelley Fitzpatrick M.Sc. Director, Health and Nutrition, Flax Canada 2015