Choline is a quaternary
amine endogenously synthesized from the
amino acid methionine or absorbed via the portal circulation. It is ubiquitous in the diet, although it has a greater presence in organ meats.
Choline is an essential component of all cell membranes, and has been considered a required dietary nutrient since 1998 by the US Institute of Medicine's Food and Nutrition Board.
Choline is necessary for DNA repair, mediated by its role as a methyl donor. It also serves as the precursor for the
neurotransmitter acetylcholine. Evidence has accumulated that hepatic steatosis, which occurs during
parenteral nutrition therapy, develops as a result of
choline deficiency because endogenous production of
choline from parenterally infused
methionine is deficient. In addition,
memory deficits and skeletal muscle abnormalities have been described, and
choline deficiency appears to activate cellular apoptosis. Provision of intravenous
choline ameliorates hepatic steatosis associated with
parenteral nutrition infusion.