Choline is produced endogenously in the liver (as phosphatidylcholine), but the amount we make isn’t sufficient to meet our body’s needs. Therefore, it’s essential to obtain choline from the diet and/or supplements. According to some estimates, adults in the United States only consume between 278 and 402 mg of choline per day, which falls below the adequate intake (AI) for choline.[1] Despite having lower-than-recommended dietary intakes of choline, most adults don’t appear to be choline-deficient, possibly due to the contribution from endogenous choline production.
The liver is the primary site for choline synthesis. Choline synthesis is catalyzed by the enzyme phosphatidylethanolamine N-methyltransferase (PEMT), which synthesizes phosphatidylcholine by methylating phosphatidylethanolamine using the methyl donor S-adenosyl-L-methionine (SAMe).