Choline catabolism

Choline is an essential water-soluble nutrient in humans, serving as a precursor of phospholipids and the neurotransmitter acetylcholine. It is often associated with B vitamins based on its chemical structure but it isn't an official B vitamin. Its oxidation to betaine provides a link to folate-dependent, one-carbon metabolism where betaine is a methyl donor in the methionine cycle. Betaine is further metabolised to dimethylglycine which is cleared by the kidney.

Summary from Reactome (R-HSA-6798163), read 2026-09-23.