>Thus, it is likely that no one on parenteral feeding "technically" dies of
>nutrient deficiency since the diet ensures that they get all of the known
>essential nutrients. The problem is that first there are likely still some
>unknown important nutrients and the term essential as defined above is not
>necessarily sufficient to keep one alive for very long.
I'm sorry I don't remember the details, but the problem with long-term
feeding is not nutritional deficiencies. The problem is that dumping the
directly into the bloodstream disturbs one of the fundamental balances -
acid/base, osmotic, electrolyte; I forget which. Long-term, either you have
starve the patient (not enough calories) or you will kill them by deranging
their body chemistry. It's not the food content, it's the intake mechanism.
People can and are maintained indefinitely on elemental diets, in which all
is synthetic. We don't know enough to maintain optimal health indefinitely,
we can manage adequate health with just the nutrients we know about.