roberta,

http://www.martekbio.com/abstracts/lipids26.html
http://www.efamol.com/stordy/articles.html

flax only supplies short chain fatty acids, and not long-chains.  it appears
some people must eat long-chain fatty acids in foods for proper brain
functioning, heart, etc.  this is why consumption of fish is linked with lower
heart disease, so they say...

aaron