D3-PC from the PEMT pathway
To estimate the use of different D9-choline supplements for their contribution to methyl group metabolism and PC synthesis via PE methylation to form PC via the PEMT pathway, we investigated the plasma concentrations of D3-PC in response to D9-choline supplements. In this pathway, (D9-)betaine from (D9-)choline oxidation is required to synthesise (D3-) methionine, which after activation to (D3-)-S-adenosylmethionine is used to form D3- (and D6) PC [