>From my (limited) understanding of general nutrition,
essential anything, (amino acid, fatty acid etc), simply
means the organism's metabolism is unable to produce
the substance via it's own biochemical pathways and
relys on diet content.
Conversely, non-essential means the substance can
be produced by the organism and doesn't necessarily
have to part of the food intake.
Regards
Keith
Keith.Hand at wmc.com.au